Operating Instructions METTLER TOLEDO DL37 KF Coulometer · 2. Introduction 6 2.1 Measurement...

Operating Instructions

METTLER TOLEDODL37 KF Coulometer

Contents

METTLER TOLEDO DL37 1

Contents Page

1. Safety measures 5

2. Introduction 6

2.1 Measurement principle 7

3. Setting up the system 8

3.1 Identification of parts 83.2 Checking the operating voltage 103.3 Printer paper loading 113.4 Installing the titration vessel 123.5 Balance connection 13

4. Method configuration 14

4.1 General 144.1.1 Basic structure 144.1.2 Structure of the method parameter configuration 154.1.3 Initial parameters in method No. 1 - 5 174.2 Titration Parameters (Titr Para) 184.2.1 Endpoint of the titration (Limit or End Level) 194.2.2 Stirring time (Delay; sec ?) 204.2.3 Control Gain 204.2.4 Stable; ∆µg 214.2.5 Blank on / off 214.2.6 Start auto / manu 214.3 Titration parameters with DO337 Drying Oven 224.3.1 Titration parameters with DO337 connected to the DL37 224.3.2 Pretreatment possibilities 234.4 Calculation Parameters (Calcu Para) 254.5 Parameters for results printout (Print Para) 274.6 Parameters for graphics and data printout (Data List Para) 294.7 Parameters for sample size (Size Para) 314.8 Method selection and protection 344.9 Initialization of all default parameters 35

2 METTLER TOLEDO DL37

Contents

Contents Page

5. Titration 36

5.1 Status diagram of titration 365.2 The first titration 375.3 Pretitration 385.4 Titration with manual or automatic start 405.5 Weight entry: before, during or after the titration 415.5.1 Sample weight entry before the start of the titration 415.5.2 Sample weight entry during the titration 415.5.3 Sample weight entry after the titration 425.6 Weight entry: automatic from the connected balance 435.7 Series titration 455.8 Water determination in solid samples by external extraction 475.8.1 Titration of solid samples by an external dissolution 485.8.2 Titration of solid samples by an external extraction 515.9 Water determination using DO337 Drying Oven 52

6. Functions 54

6.1 General 546.2 Reagent life: display, initialization and alarm setting (FUNCTION 0) 556.3 Recalculation (FUNCTION 1) 576.4 Statistical evaluation of titration series (FUNCTION 2) 586.5 Statistical evaluation of manually entered data (FUNCTION 3) 596.6 Statistics: Deletion of single results in series (FUNCTION 4) 606.7 Date and time setting (FUNCTION 5) 616.8 RS-232C interfacing (FUNCTION 6) 626.9 Display of the polarization potential and the results (FUNCTION 7) 636.10 Purging during DO337 conditioning (FUNCTION 8) 64

7. Special Keys 66

7.1 The – Key (the key with the switch function) 667.2 The RESET Key 677.3 The STIRRER and SPEED Keys 677.4 The PRINT Key 687.5 Instrument identification 69

Contents


Contents Page

8. Maintenance 70

8. Charging of memory backup battery 708.2 Application of grease 708.3 Septum replacement 708.4 Silica gel replacement 708.5 Long-term storage measures 708.6 Catholyte replacement 718.7 Anolyte replacement 718.8 Cleaning detection electrode 728.9 Cleaning inner burette 728.9.1 Cleaning steps 728.9.2 Drying steps 73

9. Troubleshooting 74

9.1 Error messages and malfunction rectification 749.2 Power switch failure 769.3 Stirrer malfunction 779.4 Background level excessive 789.5 Excess reagent consumption 799.6 Endpoint not reached or reached too late 809.7 Poor reproducibility of results 819.8 Glass contact areas jammed 82

10. Standard Equipment and Optional Accessories 83

Appendix

A Schematic Diagram 88B Specifications 89C Display messages list 91D Index 98E ISO 9001 certificate for METTLER TOLEDO 101

Declaration of System Validation 102


Contents

FCC rules

This equipment has been tested and found to comply with the limits for a Class A digitaldevice, pursuant to both Part 15 of the FCC Rules and the radio interference regulations ofthe Canadian Department of Communications. These limits are designed to provide reason-able protection against harmful interference when the equipment is operated in a commer-cial environment. This equipment generates, uses and can radiate radio frequency energyand, if not installed and used in accordance with the instruction manual, may cause harmfulinterference to radio communications. Operation of this equipment in a residential area is liketo cause harmful interference in which case the user will be required to correct the interfer-ence at his own expense.

Fcc rules

Safety measures


1. Safety measures

The DL37 has been tested for the experiments and intended purposes documented in theseOperating Instructions. However, this does not absolve you from the responsibility ofperforming your own tests of the product supplied by us regarding its suitability for themethods and purposes you intend to use it for. You should therefore observe the followingsafety measures.

Measures for your protection

– Ensure that you plug the power cable supplied into a receptacle outlet thatis grounded! In the absence of grounding, a technical fault could be lethal.

– Switch the instrument off and disconnect the power cable before you openthe housing or change blown fuses! An electric shock could be lethal.

– Never work in an environment subject to explosion hazards! The housingof the instrument is not gas tight (explosion hazard due to spark formation,corrosion caused by the ingress of gases).

– When using chemicals and solvents, comply with the instructions of theproducer and the general lab safety rules!

Measures for operational safety

– Check the set operating voltage before you switch on the instrument! Theinstrument may suffer damage if the operating voltage does not match theline voltage.

– Use only fuses of the type specified in the Operating Instructions! (Risk offire)

– Have the instrument serviced only by METTLER TOLEDO Service!

– Always wipe off splashed liquids immediately! The instrument is notwater-proof.

– Exclude the following environmental influences:• powerful vibrations,• direct sunlight,• atmospheric humidity greater than 80%,• temperatures below 5 °C and above 35 °C,• powerful electric or magnetic fields!

Introduction


2. Introduction

Moisture in sugar or salt influences its pouring properties. Traces of moisture in brake fluidadversely affect the function of the vehicle brakes. Small amounts of water in aircrafthydraulic oil increase the risk of an emergency. Traces of moisture usually influence thequality of products and it is therefore often very important to know the exact value of themoisture content. With the METTLER DL37 KF Coulometer you can easily determine tracesof water with a very high degree of accuracy.

The DL37 has five built-in methods.

With the DL37 you have the possibility to adapt the titration parameters (control gain, endpoint indication, etc.) to your titration problem to obtain an optimal measurement procedure(short titration time, high accuracy).

The DL37 has an automatic start mode. You inject the sample, the titration then startsautomatically as soon as the DL37 detects the added water.

The DL37 offers the possibility of entering the sample weight before, during or after thetitration; manually or transferred automatically from the connected balance.

The DL37 and METTLER DO337 Drying Oven can be connected to a highly automatedsystem. This system enables you to determine water in solids in an extremely simpleoperation.

The DL37 has an automatic background (drift) determination, which is reconciled in theresult calculation.

The DL37 has a statistical evaluation feature (mean, standard deviation and coefficient ofvariance) and allows recalculation of results.

The DL37 has a highly flexible result printout.It is possible to print out the titration curve and a list of the titration data (time, moisturecontent within time interval and accumulated moisture content).

Introduction


Inner burette

Catholyte

Cathode

Membrane

Anode

Detection electrode(double platinum pin electrode)

Titration vessel

Anolyte

Rotor

Detection/control unit Microcomputer

Display

Printer

2.1 Measurement principle

In the Karl Fischer moisture content measurement, water reacts with iodine and sulfurdioxide in the presence of a base and an alcohol.

H2O + I

2 + SO

2 + CH

3OH + 3RN 1 [RNH] SO

4CH

3 + 2[RNH]I (1)

In the volumetric titration, iodine is added as a titrant. In the coulometric technique, iodine iselectrolytically generated in the anolyte, which contains iodide.

2I I2 + 2e (2)

As long as water is present in the titration vessel the generated iodine reacts accordingto (1).As soon as all the water has reacted, a small excess of iodine appears in the anolyte. Thisiodine is detected by the double platinum pin electrode and the iodine production is stopped.According to Faraday’s law, the quantity of iodine produced is proportional to the currentgenerated. In equation (1), I

2 and H

2O react with each other in proportion 1:1. Therefore a

mole of water (18 g) is equivalent to 2 x 96,500 coulombs, or 10.72 coulombs/1 mg H2O. The

total amount of moisture can thus be determined by measuring the total consumption ofelectricity.

– –1

Setting up the system


3. Setting up the system

3.1 Identification of parts

0 IRS-232C BALANCE

Electronic balanceinterface (option)

Computer interface(RS232) (option)

Power switch

Printer

Titration cell desiccatorInner burette(integrated cathode/anodecombination)

Detection electrode(double platinum pin electrode)

Septum (syringe inlet port)

Titration cell

Titration cell holder

Display :Indicates method No.,background level,status and data

Keypad



Keypad

1 1 1

STIRRER

SPEED

RESET

PRINT

-

FUNCTION

RESULT

SIZE

TITR.PARA

METHOD

1

0

4

7

2

.

5

8

3

6

9

CLEAR

ENTER

PRE-TITR

1 . 3 2 * 1 2 3 4 5 µ g.

START

METHOD µg/sec COND DATA

Keys:

METHOD Key for method selection (see chapter 4.8)TITR.PARA Key for setting titration parameters (see chapter 4.2)RESULT Key for setting calculation and printing parameters (see chapter 4.4 - 4.6)SIZE Key for entering sample No. and sample weight (see chapter 4.7)

PRE-TITR Key to start the pretitration (see chapter 5.3)FUNCTION Key for special functions (see chapter 6)STIRRER Key to switch the stirrer on/off (see chapter 7.3)SPEED Key to set the stirrer speed (see chapter 7.3)

PRINT Key to print out all methods and function parameters (see chapter 7.4)RESET Key to reset all functions (see chapter 7.2)START Key to start a titration (see chapter 5)

CLEAR Key to clear an entryENTER Key to confirm a parameter entry

Display:

METHOD Display of the selected methodµg/sec Display of the background level (drift)COND Display of the status * During pretitration

Ready for titrationDATA Display of the moisture content during titration



3.2 Checking the operating voltage

Before switching on the instrument for the first time, make sure the voltage selector is set tothe appropriate line voltage.

Connection to DO337

AC power

Voltage selector

Line voltage Setting of voltage Fuse selector

100 V, 50 Hz 100 V T3,15L250V

120 V, 50/60 Hz 120 V T3,15L250V

220 V, 50 Hz 220 V T1,6L250V

230/240 V, 50 Hz 240 V T1,6L250V

Voltage can be selected by the selector on the rear panel.

Slottedscrewdriver Voltage

selector

Spare fuse Current fuse



• Lead paper under the drum.

• Select Print Titr. Para.

3.3 Printer paper loading

• Load a new roll of paper on the holder bar and place in position.

• Tear off excess paper.



3.4 Installing the titration vessel

Set the power switch (on the side panel) to the OFF position.

Connect the detection electrode, the anode and cathode as shown in the illustration.

white

red

Filling the titration vessel with reagent

Do not inhale or allow skin contact of Karl Fischer reagents! They arepotentially hazardous.

Anolyte• Pour 100 mL of anolyte into the titration vessel.

Catholyte• Pour about 5 mL of catholyte into the cathode of the inner burette.

Note : Adjust the catholyte level up to the “100” mark on the titration vessel.

See also chapter 6.2: Reagent life.

WARNING



ON

1 2 3 4

3.5 Balance connection

When a balance is connected to the titrator, the sample weight can be transferred directly tothe titrator.

METTLER TOLEDO PM Balance

Use a PM data interface and balance connection cable ME-105086.

The data output of the connected PM balance must be configured as follows:

• Send Continuous Mode

• 2400 baud

• even parity

METTLER TOLEDO AE Balance

Use Option 011 and balance connection cable ME-59348.

The data output of the connected AE balance must be configured as follows:

• Send Continuous Mode

• 2400 baud

• even parity

• cable shielding floating (no coding plug)

METTLER TOLEDO AT Balance

Use balance connection cable ME-105086.

The data output of the connected AT balance must be configured as follows:

• Cont (Send Continuous Mode)

• 2400 bd (2400 baud)

• PAr E (even parity)

• HS Pause

• EOL cLF

METTLER TOLEDO AG/AB/PB/PR Balances

Use LC-RS25 cable ME-229050.

Using the 3 switches, the cable must be configured as follows:

• 7 (left switch) attachment of the DL37

• 3 (middle switch) 2400 baud

• 4 (right switch) 7 bit, even parity, nonesend continuous mode

6

21

7 5

43

0

6

21

7 5

43

0

6

21

7 5

43

0

Method configuration


4. Method configuration

4.1 General

The METTLER DL37 KF Coulometer has 5 methods stored for the determination of water.Each method contains all parameters which are used for the titration, the calculation and therecord of a titration. These parameters can be modified to meet the requirements ofindividual titrations using the three function keys TITR.PARA, RESULT and SIZE.

1 1 1

STIRRER

SPEED

RESET

PRINT

-

FUNCTION

RESULT

SIZE

TITR.PARA

METHOD

1

0

4

7

2

.

5

8

3

6

9

CLEAR

ENTER

PRE-TITR

1 . 3 2 * 1 2 3 4 5 µ g.

START


In a new METTLER DL37 KF Coulometer all 5 methods are initialized with default parame-ters for 5 different titrations (see 4.1.3.). With these methods you can start a titration withoutany change of parameter configuration.

4.1.1 Basic structure

A method consists of 5 groups of parameters, which can be selected with the three functionkeys TITR.PARA, RESULT and SIZE

Function key Parameter group Description

TITR. PARA Titr. Para (parameters for controlling the titration)

RESULT Calcu Para (parameters for the result calculation)Print Para (parameters for the result printout)Data List Para (parameters for graphics and data printout )

SIZE Size (parameters for the sample)



4.1.2 Structure of the method parameter configuration

For entering and changing these display lines, see the chapters 4.2, 4.5, 4.6, 4.7.

Oven Temp; ? (10-300°)Pretreat; 1-3 ?Back; sec ?Sampler; sec ?Cell; sec ?

TITR.PARA

Delay; sec ? (0-9999 sec)Limit; sec ? (0-9999 sec)Control Gain? (1-10)End Level; off / on End Level ? (0-9999 sec)

Stable; ∆µg ?Blank; on / offStart; auto / manuOven; off / on

RESULT

Calcu No. : 1 , 5-6Dimension : µg/mg ppm/%Wt : variable / constant

CALCU PARA

Format fixed / variable

PRINT PARA

Sample No. ;Date ;Lot No. ;Method No. ;Calcu No. ;Size ;Result ;End Level ;Back Ground ;Reagent ;Meas. Time ;

Sample No. : on

Size : on

Result : on

(rest off)

on / offon / offon / offon / offon / offon / offon / offon / offon / offon / offon / off

Print Time ? (10-999 sec)Data List : on / offGraphic :off / Form 1 / Form 2

DATA LIST PARA



Calcu No. 3 , 6 :Sample No. ; ? 01-01Lot ?BG ; µg/sec ?Wt 1 ; g ?Wt 2 ; g ?Wt 0 ; g ?B ; g ?A ; ppm ?

SIZE

Sample No.; ? 01-01Lot; ?BG; µg/sec ?Wt 1; g ?Wt 2; g ?Wt 0; g ?B; g ?A; ppm ?V1; ml ?Dens; g/ml ?V2; l ?Temp; °C ?

Calcu No. 1:Sample No.; ? 01-01Lot ?BG ? µg/sec

The structure depends on the calculation method (Calcu No.)

Calcu No. 2 :Sample No.; 01-01Lot ?BG : µg/sec ?Wt 1 : g ?Wt 2 : g ?

Calcu No. 4Sample No.; ? 01-01Lot ?BG ; µg/sec ?V1 ; ml ?Dens ; g/ml ?

Calcu No. 5 :Sample No. ; ? 01-01Lot ?BG ; µg/sec ?V2 ; l ?Temp ; °C ?



4.1.3 Initial parameters in method No. 1 - 5

Delay; sec?Limit; sec?Control Gain?End Level; on ↑End Level?Stable; ∆µg?Blank; on ↑Start; auto ↑Oven; on ↑Oven; Tem?Pretreat; 1-3?Back; sec?Sampler; sec?Cell; sec?

Calcu No., 1 - 6

Dimension; ppm ↑Variable Wt ↑

Fixed Format ↑

Print Time?

Data List; off ↑Graphic; off ↑

Sample No.?Lot?Wt1; g?Wt2; g?

TITR.PARA

CALCU.PARA

PRINT.PARA

DATALIST.PARA

SIZE

00

5.0on

0.1 µg/sec0.1 µg/min

onautooff

1

µg

Fixed FormatSample No.SizeResult

30 sec

off

off

01 - 01

00

5.0on

0.1 µg/sec0.1 µg/min

onautooff

2

ppm

Variable


30 sec

off

off

01 - 01

5.000 g0.0 g

01200 sec

5.0off

0.1 µg/minon

autoon

150 °C1

180 sec180 sec120 sec

2

ppm

Variable


30 sec

off

off

01 - 01

5.000 g0.0 g

01200 sec

5.0off

0.1 µg/minon

autoon

150 °C1

180 sec180 sec120 sec

2

ppm

Variable


30 sec

off

off

01 - 01

5.000 g0.0 g

01200 sec

5.0off

0.1 µg/minon

autooff

2

ppm

Variable


30 sec

off

off

01 - 01

5.000 g0.0 g

Sample measurement Direct liquid samplemeasurement

Measurement of plastics,powder and samples withDO337 Drying oven

Parameter

Method

1

• Every method No. can be configured as a method together with a drying oven. Basically,the structure of every method can be changed to any desired form.

• Methods 1 and 2 can therefore also be configured with the DO337 Drying Oven.

532 4



4.2 Titration Parameters (Titr Para)

Here you can set the control parameters for the titration.

Note

All parameters with the 3 sign can be changed with the – key, see also chapter 7.1.

All parameters with the ? sign require entry of a numeric value.

Display Description

Delay ; sec ? Stirring time before titration. (0 - 9999 sec)

After pressing the START key the countdown of the remaining stirringtime is displayed.

Limit ; sec ? Titration time. (0 - 9999 sec)

A titration will be terminated after the time limit, if no end point is found.The time limit is not active if set to 0; in this case End Level must be set ON.

Control Gain ? Control Gain (1 - 9)

Use 2 - 3 for high reaction rate, 7 - 8 for low reaction rate, 4 - 6 normal.

(Never use 0, iodine will not be generated.)

End Level ; on 3 Titration termination by End Level

ON: A titration will be terminated when End Level is reached.

OFF: A titration will be terminated after the time limit.

End Level ? Value for End Level (0 - 999 µg/sec) normal 0.1 µg/secValue above the baseline which determines the end point,baseline = background level (drift) before sample injection.

Stable ; ∆ µg ? Change in the background (drift) (0 - 999 ∆µg/min) normal 0.1 µg/minFor status change Ready - Stable, see chapter 5.3.

Blank ; on 3 Automatic or manual background level (drift) compensation

ON: The background level (drift) is automatically compensated.

OFF: The background level (drift) is compensated by a manually enteredvalue with the SIZE parameters. See chapter 4.7.

Start ; auto 3 Automatic start of the titration (see also chapter 5.4)

AUTO: Automatic start of the titration when moisture is detected

MANU: Start of the titration with the START key

Oven off 3 DO337 Drying Oven connected

ON: DO337 Drying Oven connected.1 additional parameters, see chapter 4.3.

OFF: DO337 Drying Oven not connected



4.2.1 Endpoint of the titration (Limit or End Level)

With the DL37 you have two possibilities to determine an endpoint.a) Limit

You define a fixed titration time. The titration stops after the defined time.b) End Level

You define an endpoint level. When the endpoint level is reached, the titration stops.

You must define a Limit or an End Level, or both.

If you define nothing, in other words Limit 0 sec and End Level OFF, you get an errormessage: Para set miss!If you set both, the first condition to be satisfied, stops the titration.

Remarks regarding Limit

The fixed titration time is used especially with the DO337 Drying Oven. As the Drying Ovenis often very slow, an endpoint indication with the End Level would take a very long time.The fixed titration time is also used for titrations with a sluggish approach to the endpoint(due to side-reactions), especially if the end point level is not known.To switch off fixed titration time, set Limit to 0 sec.

Remarks regarding End Level

A higher value of the End Level reduces the titration time, but the titration error increases,especially if the sample releases its moisture slowly.Repeated analysis of an oil sample sometimes causes a shift to a higher background level(drift). In this case a low End Level setting results in failure to detect the endpoint.

In the case of titrations with a sluggish approach towards the endpoint (due to side-reactions), a higher End Level can help reduce the error.



Titration curves of a rapid and a slow moisture release with two End Levels:

A: Background level (drift)L1: High endpoint level (high value for End Level)L2: Low endpoint level (low value for End Level)End1 Endpoint with the high End LevelEnd2 Endpoint with the low End Level

If the End Level is set to 0 (with End Level ON), the titration will proceed until the backgroundlevel (drift) reaches the value before sample injection.

4.2.2 Stirring time (Delay ; sec ?)

If you have defined a stirring time, the countdown of the remaining stirring time will bedisplayed after you have pressed the START key.You can use the stirring time with manual and automatic start.If you want to terminate the current stirring time, press the START key again and the titrationwill start immediately.

4.2.3 Control Gain

The control gain is used to control the iodine production. With a high value of Control Gainthe iodine production will be faster and therefore the titration time shorter, but the risk of over-titration will also be higher.For an optimal titration (short titration time without over-titration), the Control Gain must beadapted to the reaction rate.For normal reaction rates, use Control Gain 4 - 6.For low reaction rates (slow water release of the sample), use Control Gain 7 - 8.For high reaction rates use a low Control Gain 2 - 3 to avoid over-titration.

Start End 1 End 1

End 2 End 2

Start

µg H2O / sec

L1L2

A



4.2.4 Stable ; ∆µg

After a pretitration or titration the DL37 has two status modes: Ready or Stable.In these two modes, the titration cell is kept free from water by continuous titration.Status Ready: Background (drift) is not stable.Status Stable: Background (drift) is stable.

The change from status Ready to Stable is defined with the parameter Stable.For example: Stable = 0.1 µg/min (background (drift) deviation per minute)If the change in the background (drift) is 0.1 µg/min or less, the status is Stable.If the change in the background (drift) is more than 0.1 µg / min, the status is Ready.The change to the status Stable does not depend on the background level (drift), but on thebackground (drift) stability. It is possible to be in the Stable mode with a high but stablebackground (drift).

See also chapter 5.3.

4.2.5 Blank on / off (automatic or manual background (drift) compensation)

Blank on:

The background level (drift) is automatically compensated by the measured value of thebackground level (drift) before sample injection.Normally Blank “on” should be used.

Blank off:

The background level (drift) is compensated by the value entered through the SIZE parame-ters (BG µg/sec ; ?). See chapter 4.7.When Blank “off” is selected, the background titration will be stopped by pressing theSTART key in the automatic and manual start mode.

4.2.6 Start auto / manu

Start auto:

Automatic start of the titration: Press the START key, the titration starts automatically assoon as the DL37 detects the added moisture. If no moisture is detected within 1 minute afterpressing the Start key, the DL37 will reset itself. If the parameter Blank is set to “on”, theDL37 compensates the background (drift) until the added sample is detected.

Start manu:

Manual start of the titration: Press the START key, inject the sample and press the STARTkey again to start the titration.After the START key is pressed for the first time, the background titration stops.See also chapter 5.4. Titration with manual or automatic start.



4.3 Titration parameters with DO337 Drying Oven

4.3.1 Titration parameters with DO337 connected to the DL37

In order to use the DL37 with the DO337 as a highly automated system, you must set theparameter Oven to “on”.

Display Description

Oven on 3 DO337 Drying Oven connected

ON: DO337 Drying Oven connected

OFF: DO337 Drying Oven not connected

Oven Temp. ? Set temperature for the DO337 (0 - 300 °C)

Pretreat; 1-3 ? Possibilities for the pretreatment (1-3)

For more details, see chapter 4.3.2

Back; sec ? Time of back-purging (normally 180 sec)

For more details, see Fig. 1

Sampler; sec ? Time of sampler purging (for eggplant-shaped sampler) (normally180 sec)

This is applied only with Pretreat 1


Cell; sec ? Time for cell purging (normally 120 sec)


Carrier gas Back purge Carrier gas

Cell purging

Fig. 1: Back-purging Fig. 2: Sampler purging Fig. 3: Cell purging

Carrier gas

Sampler purgingEggplant-shaped samp



4.3.2 Pretreatment possibilities

Pretreat 1 (with the eggplant-type sampler)

Place the sample in the eggplant-type sampler and insert the sampler in the sample inlet ofthe DO337. Start the measurement sequence by pressing the START key, the sample boatwill then move automatically to the sample inlet, back-purging will be performed (see Fig. 1),followed by sampler purging (see Fig. 2) and finally cell purging (see Fig. 3). The DL37 willwait for background (drift) stability and will then tell you to insert the sample (you rotate theeggplant sampler to transfer the sample to the sample boat). After the START key has beenpressed again, the sample boat will be moved automatically into the heating section.(For more details, see Operating Instructions of the DO337.)

Eggplant-typesampler

Sample boat

Heating tube Rotate

Pretreat;1-3 ? 1

Back ; sec ?

Sampler ; sec ?

Cell ; sec ?

END

Select a BACK PURGETIME(normally to 180 sec)

Select a PURGE TIMEfor the eggplant-type sampler(normally to 180 sec)

Set a CELL PURGETIME(normally to 120 sec)



Pretreat 2 (direct sample insertion through the sample inlet)

Press the START key to start a measurement sequence. The sample boat moves to thesample inlet, back-purging is performed (see Fig. 1), followed by cell purging (see Fig. 3).When the background becomes stable, insert the sample directly in the sample boat throughthe sample inlet port. Press START and the sample boat will be moved automatically into theheating area. (For more details, see chapter 5.9 or the Operating Instructions of the DO337.)

Pretreat 3 (placement of the weighed sample in the sample boat)

Place a weighed sample in a dry sample boat and position the boat below the sample inlet.Press the START key to start a measurement sequence. Back-purging will be performed(see Fig. 1), followed by cell purging (see Fig. 3). When the background becomes stable,press START and the sample boat will be moved into the heating area.(For more details, see the Operating Instructions DO337.)

Pretreat;1-3 ? 2

Back ; sec ?

Cell ; sec ?

END



Pretreat;1-3 ? 3

Back ; sec ?

Cell ; sec ?

END





4.4 Calculation Parameters (Calcu Para)

The three calculation parameters are part of the result parameters you can select in amethod.The calculation parameters needed for every sample must be entered through the SIZEparameters, see chapter 4.7.

Entry key Display Description

RESULT Data List Para ↑ Select Calcu Para ↑ with the

– key

– Calcu Para ↑

ENTER Calcu No.:1-6? 1 Set the formula No.

2 Calcu No.:1-6? 2 (formulas, see next page)

ENTER Dimension: % ↑ Set the calculation result unit

– Dimension: ppm ↑

ENTER Constant Wt ↑ Constant sample size

– Variable Wt ↑ Variable sample size

ENTER

Constant sample size

If you choose constant sample size, the DL37 will use the same sample size for everytitration. This sample size must be entered as a SIZE parameter. The DL37 will not thenrequest a weight entry.

Variable sample size

If you choose variable sample size, you can enter the sample size before, during or after thetitration. If you do not change the sample size before or during the titration (with the SIZEparameter), the DL37 will request the sample size after the titration.If you have changed the sample size before or during the titration, the DL37 knows that youhave already entered a value and will thus not request a weight.See also chapter 5.5.

Note

You can change all parameters with the ↑ sign using the – key; see also chapter 7.1.



Calculation formula (Calcu No 1 - 6)Data Result of the titration (in mg water)BG Background level (entered with the SIZE key), used when the Blank parameter is set to off.t Measurement time

1 when Blank is set to on: The background (drift) is automatically compensated in the result calculati-on.

Wt1 Total weight (sample & syringe) (in g)Wt2 Weight (syringe) (in g)A Moisture content of the solvent only (in ppm)B Total amount of solvent for the external extraction (or external dissolution) (in g)Wt0 Weight of the sample entered in B solvent (in g)V1 Injected volume of the sample (mL)Dens Density of the sample (g/mL)V2 Volume of the gas sample (L)T Temperature of the gas sample (°C)22.4 Gas volume of 1 mole at 273 K18 Molecular weight of water

FormulaNo.

1

2

3

4

5

6

Description

Moisture calculation (default).Result in µg or mg.

Concentration calculation for weighed liquidor solid samples.Result in ppm or %.

Concentration calculation forexternal dissolution of liquid or solidsamples (sample dissolved in the solvent).Result in ppm or %.

Concentration calculation for volumetricallymeasured samples.Result in ppm or %.

Concentration calculation for volumetricallymeasured gaseous samples.Result in ppm or %.

Concentration calculation forexternal extraction of solid samples(sample insoluble in the solvent).Result in ppm or %.

Formula

(Data - BG x t)BG = Background level entered with the SIZE keywith Blank offt = Measurement time

Data -BG x t

Wt1- Wt2 x 1000 (ppm)

( )

Data -BG x t

Wt1- Wt2 x

B + Wt0Wt0

x 1000

- AxBWt0

(ppm)

( )

Data -BG x t

V1 x Dens x 1000 (ppm)

( )

Data -BG x t

Wt1- Wt2 x

BWt0

x 1000 -A x BWt0

(ppm)( )

Data -BG x t x 22,4

V2 x 18 x 1+

T273

x 1000 (ppm)( )



4.5 Parameters for results printout (Print Para)

The Print parameters allow you to define the format of your printout for a particular method.

With fixed format, Result, Size (sample weight) and Sample No. are automatically printedout.

With variable format, you can select the different items to be printed out.


RESULT Calcu Para 3 Select Print Para 3 with the - key.

– Print Para 3

ENTER Fixed Format 3 Select the measurement resultprintout format.

– Variable Format 3 Select the print/no-print of the fol-

lowing items.

ENTER Sample No.; on 3 Sample No.

ENTER Date; on 3 Date

ENTER Lot No.; off 3 Lot No.

ENTER Method No.; off 3 Method No.

ENTER Calcu No.; on 3 Formula No.

ENTER Size; on 3 Size parameter

ENTER Result; on 3 Calculation result

ENTER End Level; on 3 End point level

ENTER Back Ground; on 3 Background level

ENTER Reagent; off 3 Reagent life

ENTER Meas. Time; on 3 Measurement time required

Note

You can change all parameters with the 3 sign using the – key; see also chapter 7.1.



Result printout with fixed format. Result printout with variable format.Selection from above



4.6 Parameters for graphics and data printout (Data List Para)

The Data List parameters allow you to select the time interval at which the determinedmoisture content and the accumulated moisture content will be printed out (= data list). Youcan also choose between two graphical representations.

Note

You can change all parameters with the ↑ sign using the — key, see also chapter 7.1.


RESULT Print Para ↑

– Data List Para ↑ Select Data List Para ↑

ENTER Print Time? 30 Select the data list printing interval

6 0 Print Time? 60 The moisture content is stored in

memory at this interval (up to 128data point in memory)

ENTER Data List; off ↑ Select the print/no-print of the datalist

– Data List; on ↑

ENTER Graphic; off ↑ Select the graphical representation(1 or 2) (see next page)

– Graphic; Form 1 ↑

– Graphic; Form 2 ↑

ENTER



Graphic Form 1 Graphic Form 2

TIme vs. moisturecontent per interval

TIme vs. integratedmoisture content (µg)

Measurement timelapsed (min.:sec.)

Integrated moisturecontent (µg)

Moisture contentwithin an interval (µg)

Time

Time

elapsed (min:sec)



4.7 Parameters for sample size (Size Para)

The Size parameters allow you to define sample identification parameters and other para-meters related to the result calculation.The parameters related to the result calculation depend on the calculation formula chosenfor the active method.

List of all SIZE parameters:

Message Description

Sample No. ? 01-01 Enter the sample No.

Lot? Enter the lot No.

BG; µg/sec? 0 Enter the background level.Note: This is displayed only when the titration parameter Blank is off

(see also chapter 4.2.5).

Wt1; g? 5.000 Sample size with tare (g).

Wt2; g? 0.0 Remainder with tare (g).

Wt0; g? 5.000 Sample weight in extraction solvent (g).

B; g? 0.0 Extraction solvent weight (g).

A; ppm? 0.0 Moisture content in extraction solvent (ppm).

V1; ml? 1.00 Injected sample volume (ml).

Dens; g/ml? 1.000 Sample density (g/ml).

V2; l? 1.000 Gaseous sample volume (l).Temp; °C? 25.0 Gas temperature (°C).

Sample No.S a m p l e N o.? 0 1 - 0 1

Lower Sample No. 1 Sample No. of the series (01 - 99)

Higher Sample No. 1 Series No. (01 - 99)

With every titration the Lower Sample No. is automatically incremented by one.

To start a new series, enter a new Higher Sample No. (the Lower Sample No. will beautomatically set to 01). By entering a Higher Sample No. the results memory of this SeriesNo. will be cleared.For statistical evaluation, see also chapters 6.4.and 6.6.For series titration, see also chapter 5.7.

To enter only a Lower Sample No.: Press – 0 5 ENTER 1 XX - 05 is set.



Regarding Lot No.:

You can use the Lot No. for the sample identification. To enter the Lot No. you can use all

numeric keys and also the – key. (The – key has no special function in this case.)

Regarding Wt0, Wt1 and Wt2

You can use these weights manually or with the – key if a balance is connected to theDL37. See also chapter 5.5. and 5.6.

The structure of the SIZE menu depends on the chosen calculation method (Calcu No.).If the calculation method needs definite parameters, these parameters will automatically berequested in the SIZE menu.

Calcu No. 3 , 6 :Sample No. ; ? 01-01Lot ?BG ; µg/sec ?Wt 1 ; g ?Wt 2 ; g ?Wt 0 ; g ?B ; g ?A ; ppm ?

Calcu No. 1:Sample No.; ? 01-01Lot ?BG ? µg/sec

The structure depends on the calculation method (Calcu No.)

Calcu No. 2 :Sample No.; 01-01Lot ?BG : µg/sec ?Wt 1 : g ?Wt 2 : g ?

Calcu No. 4Sample No.; ? 01-01Lot ?BG ; µg/sec ?V1 ; ml ?Dens ; g/ml ?

Calcu No. 5 :Sample No. ; ? 01-01Lot ?BG ; µg/sec ?V2 ; l ?Temp ; °C ?



Example of SIZE parameter entry

External dissolution 20.9498 g salicylic acid in 71.4863 g methanol.Water content of the methanol: 305.17 ppmCalculation formula No. 3


SIZE Sample No.? 01-04 Enter new sample No. to start a new

series

0 2 Sample No.? 02-01

ENTER Lot ? Enter a lot No.

8 . 4 7 – 9 0 Lot ? 8.47-90

ENTER Wt1; g ? 0.3417 Enter the sample weight before,

during or after the titration

ENTER Wt2; g ? 0.0

ENTER Wt0; g ? 0.0

2 0 . 9 4 9 8 Wt0; g ? 20.9498 Sample weight dissolved in solvent

ENTER B; g ? 0.0

7 1 . 4 8 6 3 B; g ? 71.4863 Weight of the solvent

ENTER A; ppm? 0.0

3 0 5 . 1 7 A; ppm? 305.17 Water content of the solvent

ENTER 2 .02 Stable

SIZE Sample No.? 02-01 By resetting the sample weight

RESET 2 .02 Stable entry you can ensure that the DL37

will request the weight after thetitration



4.8 Method selection and protection

The METTLER DL37 KF Coulometer always has one of the 5 methods in its memory.

If you change some parameters, e.g. in TITR.PARA the values of the current method will beoverwritten and therefore the original method lost.

It is, however, possible to protect a method against inadvertent parameter alteration.Once a method is protected, the titration, calculation and printing parameters can not bechanged unless the protection is cancelled. The size parameters (sample No., sampleweight, etc.) are not protectable and can therefore always be changed.

If a selected method is protected, pressing the TITR.PARA or RESULT key causes an errormessage on the display: “Protected!”.

Example of method protection:


METHOD Method No.: 1-5? 1 Current preset method No. is dis-played.

2 Method No.: 1-5? 2 Enter a method No.

ENTER Protect: off 3 Select whether to protect the me-thod.

– Protect: on 3

ENTER

Note

You can change all parameters with the 3 sign using the – key, see also chapter 7.1.



4.9 Initialization of all default parameters

It is possible to reinitialize all 5 methods in the DL37 by selecting method 99.The default parameters set in the factory will be loaded again.(Parameters, see chapter 4.1.3.)

This is the procedure:


METHOD Method No.; 1 - 5 ? 1 Enter method No. 99

9 9 Method No.; 1 - 5 ? 99

ENTER All Reset (ENTER)

ENTER Switch power OFF and

after 5 sec switch power ON

Caution

If you do not switch off the DL37 after initialization (load method 99), all parameters will bechanged to undefined values!

Caution

With the above initialization other parameters will also be reset:

• Reagent Life of anolyte and catholyte set to 0.

• Reagent Life Alarm limits will be initialized (anolyte 500 mg, catholyte 200 mg).

• Reagent Life to control alarm will be switched off.

• RS-232C interface configuration will be initializied.

• Method No. 1 will become the current method.

Titration


5. Titration

5.1 Status diagram of titration

PretitrationThe solvent is titrated out

Display:"Pre-Titr "

Power on

StandbyDisplay: "Pre-Titr " flashes

PRE-TITR

ReadyBackground (drift) not stable

Display:"Ready "

StableBackground (drift) stable

Display:"Stable "

PRE-TITR

START

TITRATION

RESET

Titration


5.2 The first titration

In a new DL37 there are 5 initial methods with default parameters for 5 different titrations.(Parameters, see 4.1.3) With these methods you can start a titration without changingparameters.

Start of the first titration:

Set up the METTLER DL37 KF Coulometer as described in chapter 3.Turn on the power switch. 1 “Pre-Titr” flashes on the display.

Start pretitration:

Press the PRE-TITR key; the pretitration will start.Wait until the display shows “Stable”.The DL37 is now ready for the titration.

Choose method No 2:

Press METHOD key, enter 2 and confirm with ENTER.

Run titration

Press START key.Inject a sample using a syringe through the septum (for example 1 mL methanol).(This must be accomplished within 1 min otherwise the DL37 reverts back to the stablestate.)The titration starts automatically.When the titration is finished, the DL37 requests the sample weight:The display shows: Wt1; g ?Enter the sample weight and confirm with ENTER.The display now shows: Wt2; g ? 1 Confirm this with ENTER.The result is displayed and printed out.The DL37 is now ready to run the next titration. The titration cell is kept free from water bycontinuous titration. The display shows “Stable”.

Titration



PRE-TITR Pre-Titr (flashing) Standby

1 1.1 * Pre-Titr Pretitration1 .25 Ready Wait until the display shows

“Stable”2 .02 Stable

METHOD Method No. ; 1-5 ? 1 Choose method 2

2 Method No. ; 1-5 ? 2

ENTER Protect; off !

ENTER 2 .03 Stable DL37 is ready for titration

START 2 .01 Samp. In. Inject the sampleMust be accomplished within1 min

2 .73 * 45.8 µgWt1; g ? 5.000 Titration in progress terminated

Enter the sample weight0 . 4 7 1 9 Wt1; g ? 0.4719

ENTER Wt2; g ? 0.0

ENTER247.74 ppm The result is displayed and printed

2 .02 Stable DL37 is ready for the next titration

5.3 Pretitration

Turn on the power switch.

On the display “Pre-Titr” flashes (the DL37 is in the Standby mode).

Press the PRE-TITR key in order to start the pretitration.

If the stirrer is not active, press the STIRRER key (see also chapter 7.3)

After the pretitration the DL37 switches to the modes “Ready” and “Stable”

Status: Pre-Titr The solvent is titrated out.Status: Ready The change in the background (drift) is 0.5 µg H2O / min or less.

Ready for rough measurement.Status: Stable The change in the background (drift) is 0.1 µg H2O / min* or less

Stable background (drift). Ready for accurate measurement.The titration cell is kept water-free by continuous titration.

* This value, the background (drift) stability (∆ µg H2O / min), can be set in the titrationparameters. (Stable; ∆ µg ? ). See chapter 4.2.

Titration


It is possible to start the titration in the “Ready” or “Stable” mode.After the titration the DL37 always returns to the mode “Ready” or “Stable” depending on thebackground stability.


PRE-TITR 1 2.1 * Pre-Titr Pretitration in progress1 .35 Ready Rough measurement ready

Background (drift) not stable

2 .02 Stable High accuracy measurementreadyBackground (drift) stable

Note

If you reconfigure the DL37 or replace the reagents, a higher amount of moisture will enterthe titration vessel. In this case it may take longer to achieve the “Ready” and “Stable” status.

Display status Stable:

Stop Pretitration

In order to exit the status Pre-Titr, Ready or Stable, press the PRE-TITR key.The status indicated on the display: “Pre-Titr” flashes.During this time moisture (drift) is not titrated and the instrument is thus not ready to start atitration.To start the pretitration, press the PRE-TITR key.See also the chapter 5.1, Status diagram of titration.

µ g1 111 . 0 2 S t a b l e

Status displayBackground level(µg H2O/sec)

Method No.


Titration


5.4 Titration with manual or automatic start

With the DL37 you can choose between a manual or an automatic start. This selection canbe done in the Titration Parameters (TITR.PARA),Parameter: Start; auto / manu, see chapter 4.2.

Manual Start

With the Manual Start you start the titration with the START key, add the sample and confirmthe sample addition by pressing the START key again. After the START key is pressed forthe first time, the continuous titration to keep the cell water-free will be terminated.



2 .73 * 45.8 µg Titration in progressWt1; g ? 5.000 Enter the sample weight

0 . 4 7 1 9 Wt1; g ? 0.4719

ENTER Wt2; g ? 0.0



Automatic Start

With the Automatic Start you start the titration with the START key and add the sample;the titration starts automatically when moisture is detected.Note: If moisture is not detected within 1 minute, the moisture content is judged to be 0 andthe system reverts to the stable state.After the START key is pressed, there is a continuous titration to keep the cell water-free untila higher moisture concentration is detected; this starts the titration.


START 2 .01 Samp. In. Inject the sample2 .03 Start Display flashes!

START2 .73 * 45.8 µg Titration in progressWt1; g ? 5.000 Enter the sample weight

0 . 4 7 1 9 Wt1; g ? 0.4719

ENTER Wt2; g ? 0.0



Titration


5.5 Weight entry: before, during or after the titration

With the DL37 you can enter the sample weight before, during and after the titration.

5.5.1 Sample weight entry before the start of the titration

If you already know the sample weight before you start the titration, the weight can beentered as a SIZE parameter. The DL37 recognizes that you have already entered theweight and will not request the weight after the titration.

5.5.2 Sample weight entry during the titration

In the case of a long titration time, it is useful to enter the sample weight during the titration.It is possible to enter this weight as a SIZE parameter when a titration is running. The DL37will recognize that you have already entered the weight and will not request it after thetitration.


SIZE Sample No.? 01-01

ENTER Lot ?

ENTER Wt1; g ? 5.000 Enter the sample weight

0 . 2 7 1 9 Wt1; g ? 0.2719

ENTER Wt2; g ? 0.0

ENTER 2 .02 Stable DL37 is ready for the titration


2 .87 * 35.3 µg Titration in progress247.34 ppm The result is displayed and printed


Titration




2 .33 * 15.8 µg Titration in progress


ENTER Lot ?

ENTER Wt1; g ? 5.000 Enter the sample weight

0 . 2 7 1 9 Wt1; g ? 0.2719

ENTER Wt2; g ? 0.0

ENTER 2 .87 * 35.3 µg Titration is still in progress247.34 ppm The result is displayed and printed


5.5.3 Sample weight entry after the titration

If you do not enter the sample weight before or during the titration, the DL37 will request theweight after the titration.


START 2 .01 Samp. In Inject the sampleMust be accomplished within1 min

2 .73 * 35.8 µg Titration in progressWt1; g ? 5.000 The titration is finished

The DL37 is waiting for the weight

0 . 2 7 1 9 Wt1; g ? 0.2719

ENTER Wt2; g ? 0.0

247.34 ppm The result is displayed and printed2 .02 Stable DL37 is ready for the next titration

Caution!

Each time you run through the SIZE parameters, even if you do not change the weightparameters, the DL37 will assume a weight has been entered and will take the value in Wt1and Wt2 as the sample weight; it will then not request the weight after the titration.

Titration


Avoid an unintentional weight entry; delete the weight entry.

• If you change sample No. or Lot, terminate the first weight parameter with RESET.• If you are unsure whether a weight has already been entered for the titraiton, you can

cancel the weight entry with RESET.



ENTER Lot ?

ENTER Wt1; g ? 0.3479

RESET The weight entry is deleted

The DL37 requests the weight afterthe titration

5.6 Weight entry: automatic from the connected balance

With the DL37 you can enter the sample weight manually using the keypad or automaticallywhen a balance is connected.For information about the balance connections and configurations, see chapter 3.5.

You can activate the weight transfer by pressing the – KeyThis is possible when you have to enter a weight:

Wt1, g ? Total weight (sample & syringe)

Wt2, g ? Tare weight (syringe)

Wt0, g ? Sample weight for external extraction (Calcu No. 3)

If you determine the sample weight by back weighing, enter the weight of the sample as Wt1and set Wt2 to zero. With the weight transfer from the balance this weight will be negative,but for the result calculation the minus sign will be ignored by the DL37.

Note

The unit of weight value will not be checked.

Titration



START 2 .01 Samp. In. Inject the sample

Must be accomplished within1 min

2 .73 * 45.8 µg Titration in progressWt1; g ? 5.000 Titration terminated

Enter the sample weight

– - 0.2057

ENTER

ENTER Wt2; g ? 0.0

182.30 ppm The result is displayed and printed2 .02 Stable DL37 is ready for the next titration

Result printout with a weight transfer from the balance:

Titration


5.7 Series titration

The DL37 is suitable for series titration. The two-figure sample number includes series No.and sample No. of the series.

S a m p l e N o.? 0 1 - 0 1

Lower Sample No. 1 Sample No. of the series

Higher Sample No. 1 Series No.

Every titration automatically increments the Lower Sample No. by one.

To start a new series, enter a new Higher Sample No. (The Lower Sample No. will be auto-matically set to 01. )This entry clears the results memory for the statistics calculation.For statistical evaluation, see also chapter 6.4.and 6.6.


SIZE Sample No.? 01-01 Enter a new sample No. to start a

new series

1 7 Sample No.? 17-01

ENTER Lot ?

RESET The weight entry is deleted

The DL37 requests the weightafter the titration

Titration


Example of a series:

Titration


5.8 Water determination in solid samples by external extraction

With the DL37 it is not possible to open the syringe inlet port stopper in order to add a solidsample, as too much moisture would enter into the titration vessel.Water absorption of an open syringe inlet port during 5 seconds (approx. 50% relativhumidity) is approx. 70 µg water!

For water determination in solids you must use external dissolution or an external extractionand add the sample with a syringe.

External dissolution for solid samples which are soluble in a solvent.

External extraction for solid samples which are not soluble in a solvent.

The METTLER DL37 KF Coulometer has special calculation formulas (Calcu No. 3 and 6) forboth methods. This allows you to perform a water determination for solids without a manualcalculation.

Calculation formula No. 3 for external dissolution(for solid samples which are soluble in a solvent):

Calculation formula No. 6 for external extraction(for solid samples which are not soluble in a solvent):

Data Result of the titration (in mg water)BG Background level (entered with the SIZE key), used when the Blank parameter is

set to offt Measurement time

→ if Blank is set “on”: the background (drift) is automatically compensated in theresult calculation of the titration.

Wt1 Total weight (sample & syringe) (in g)Wt2 Weight (syringe) (in g)A Moisture content of the solvent only (in ppm)B Total amount of solvent for the external extraction (or external dissolution) (in g)Wt0 Weight of the sample entered in B solvent (in g)

Data -BG x t

Wt1- Wt2 x

B + Wt0Wt0

x 1000 -A x BWt0

ppm( )

( )

Data -BG x t

Wt1- Wt2 x

BWt0

x 1000 -A x BWt0

ppm( )

( )

Titration


5.8.1 Titration of solid samples by external dissolution

The water determination of solids which are soluble in a solvent can be performed in thefollowing manner using calculation formula No. 3:

1. Water determination of the solvent , use Calc No. 2.2. Prepare the external dissolution with this solvent.

(for example salicylic acid in methanol)3. Change calculation method: enter Calc No. 3

—> Use the same titration parameters you used for the solvent!4. Enter the external dissolution data: Wt0, A and B5. Inject the sample of the external dissolution with the syringe into the titration vessel

and start the titration.

Example: External dissolution 20.9498 g salicylic acid in 71.4863 g methanol.Water content of the methanol: 305.17 ppm

Titration



RESULT Data List Para 3 Select Calcu Para with the – key

– Calcu Para 3

ENTER Calcu No.;1 - 6 ? 2 Set the formula No.

3 Calcu No.;1 - 6 ? 3

ENTER Dimension ;ppm 3 Set the calculation result unit

ENTER Variable Wt 3

ENTER 2 .02 Stable

SIZE Sample No.? 01-04 Enter new sample No. to start a

new series

0 2 0 1 Sample No.? 02-01

ENTER Lot ?

ENTER Wt1; g ? 0.3417 Enter the sample weight later

ENTER Wt2; g ? 0.0

ENTER Wt0; g ? 0.0

2 0 . 9 4 9 8 Wt0; g ? 20.9498 Sample weight dissolved in solvent

ENTER B; g ? 0.0

7 1 . 4 8 6 3 B; g ? 71.4863 Weight of the solvent

ENTER A; ppm ?0.0

3 0 5 . 1 7 A; ppm ? 305.17 Water content of the solvent

ENTER 2 .02 Stable

SIZE Sample No.? 02-01 Reset sample weight entry so

that the DL37 requests the sampleweight after titration

RESET 2 .02 Stable

START 2 .01 Samp. In. Inject the sample

2 .73 * 15.8 µg Titration in progressWt1; g ? 0.3417 The titration is finished

The DL37 is waiting for the weight

0 . 2 3 3 1 Wt1; g ? 0.2331

ENTER Wt2; g ? 0.0

ENTER

234.47 ppm2 .04 Stable The result is displayed and printed

DL37 is ready for the next titration

Titration


Result printout: Titration of solid samples by external dissolution.Examples:External dissolution 20.9498 g salicylic acid in 71.4863 g methanol.

Water content of the methanol: 305.17 ppm

Titration


5.8.2 Titration of solid samples by external extraction

The water determination of solids which are not soluble in a solvent can be performed in thefollowing manner using calculation formula No. 6:

1. Water determination of the solvent , use Calc No. 2.

2. Prepare the external extraction with this solvent(for example sugar in chloroform).

3. Change calculation method: enter Calc No. 6.

—> Use the same titration parameters you used for the solvent!4. Enter the external extraction data: Wt0, A and B.

5. After the extraction the solid must be deposited on the bottom of the vessel. Then takea sample from the solvent above the settled solid with a syringe, inject the sample intothe titration vessel and start the titration.(Formula No. 6 takes into account that the extraction solvent is free from the addedsolid.)

Parameter entry is similar to that for the external dissolution, see 5.8.1.

Result printout of an external extraction:Examples:External extraction of 22.9329 g sugar in 77.4644 g chloroform

Water content of the chloroform: 39.284 ppm

Titration


5.9 Water determination using DO337 Drying Oven

For water determination of thermally stable solids, you can heat the sample in a Drying Ovento evaporate the moisture and transfer it to the titration cell of the DL37 using a dry inert gas.If you connect the DO337 to the DL37, all functions of the DO337 (for example: purgingcycles, temperature, sample introduction and transfer to the heating zone) are completelyautomatic and under control of the DL37.

Example: water determination of sea salt using METTLER DO337

• Install the DO337 and connect it to the DL37.(Details, see Operating Instructions of the DO337.)

• Select method No. 3, set the oven temperature to 200 °C and choose pretreat 2.• Set the gas flow rate to 200 mL/min.

• Run the purging program with FUNCTION 8 (see chapter 6.10).

• Wait until the background (drift) is stable (with cell purging).With the DO337 you normally have a higher background (drift) than in the absence of theDrying Oven: 0.2-0.5 µg/sec.

• Press the START key to start the titration.


3 .42 Stable

START Back Purge; 179 Back-purging in progressCell Purge; 119 Cell purging in progress3 .52 Ready Wait until stable is displayed3 .44 Samp. in The DO337 is waiting for sample3 .44 Start The sample is added directly throu-

gh the sample inlet in the sampleboat

START 3 .44 * 0.0 µg The sample boat is moved to theheating section

3 .73 * 45.8 µg Automatic start of the titrationWt1;g? 5.000 Titration terminated

2 . 5 6 2 Wt1;g? 2.562 The DL37 is waiting for the weight

ENTER Wt2;g? 0.0



Titration


Water determination of sea salt using METTLER DO337

Printout of the method, result and the titration curve:

Functions


6. Functions

6.1 General

The DL37 has 9 functions for additional possibilities, such as statistics calculations, recalcu-lation, reagent life control, time and date setting, etc.

With the FUNCTION key you can select these 9 functions for displaying, controlling andchanging the additional parameters.

STIRRER

SPEED

RESET

PRINT

-

FUNCTION

RESULT

SIZE

TITR.PARA

METHOD

1

0

4

7

2

.

5

8

3

6

9

CLEAR

ENTER

START

These functions are

0 Reagent Life Reagent life: display, initialization and alarm setting

1 Re-Calculation Recalculation

2 Auto Statistics Statistical evaluation of titration series

3 Manu. Statistics Statistical evaluation of manually entered data

4 Data Deletion Statistics: Deletion of single results in a series

5 Calendar Date and time setting

6 Option RS-232C interfacing

7 Display Display of the polarization potential or the results

8 Oven Purge Purging during DO337 conditioning

Functions


6.2 Reagent life: display, initialization and alarm setting (FUNCTION 0)

The reagents (catholyte and anolyte) have a limited lifetime for water determinations.100 mL anolyte are capable of determining approx. 1000 mg water.5 mL catholyte are capable of determining approx. 300 mg water.See also the specifications of the reagents.If these reagents are used after their effective lifetimes, the water contents you measure willbe too low and the titration times longer.

The DL37 calculates and accumulates the amount of water (in mg) which has beendetermined with the reagents (= reagent life).With the FUNCTION 0 you can control the reagent life of catholyte and anolyte.With this function you have following possibilities:

• The reagent life of the catholyte and the anolyte in mg water can be displayed.

• The accumulated value (reagent life) can be reset to zero when the reagents are replaced.

• The alarm limit can be switched on/off for control.

• The alarm limit for the catholyte and the anolyte can be entered in mg water.

With FUNCTION 0 PRINTyou can print Reagent Life parameters:

In this menu you can enter your name; it appears on every GLP report.

You can enter the user and the instrument identification alphanumerically using the "minus","period" and numeric keys.

When you press this key for the first time, the letter A is displayed, for the secondtime B → C → ... Z → . (period) → – (minus) → "space" → A →...

When you press this key for the first time, a "space" is displayed, for the secondtime a – (minus) → . (period) → Z → Y → ... A → – "space" →...

You must confirm each letter (character) with Enter for it to be accepted.

.

Functions



FUNCTION F.No.; 0-8?

-"User ID" "User ID" flashes in the display.

A Enter, e.g. "A. Aichert": Press the"–" key.

A_ Press the "." key repeatedly until aperiod appears.

A._

Press the "–" key repeatedly until aA. _ space appears etc.

You can enter maximum 15 char• acters.•

Reagent LifeENTER A. Life; mg? XXX Accumulated electrolytic current

(moisture-converted) of anolyte isdisplayed (mg H

2O).

0 A. Life; mg? 0 Enter 0 on anolyte replacement todelete accumulated value (reagentlife).

ENTER C. Life; mg? XXX Accumulated electrolytic current(moisture-converted) of catholyte isdisplayed (mg H

2O).

0 C. Life; mg? 0 Enter 0 on catholyte replacement todelete accumulated value (reagentlife).

ENTER Alarm Set; off ↑ Select alarm/no-alarm status forreagent life.

– Alarm Set; on ↑

ENTER A. Alarm; mg? 500 Enter alarm limit (mg H2O) ofanolyte life.

1 0 0 0 A. Alarm; mg?1000

ENTER C. Alarm; mg? 100 Enter alarm limit (mg H2O) ofcatholyte life.

2 0 0 C. Alarm; mg? 200

ENTER

ENTER

ENTER

ENTER

0

ENTER

Functions



FUNCTION F No.; 0-8?

1 Re-Calculation

ENTER Low Samp No.? 01 Enter lower sample No.

0 5 Low Samp No.? 05

ENTER Data Set? (ENTER) Displayed if no data exists.

ENTER Moisture? 0.0

1 2 3 4 Moisture? 1234 Enter moisture content in µg H2O.

ENTER

6.3 Recalculation (FUNCTION 1)

After a titration you can change the parameters and perform a recalculation. You canrecalculate all results in a series.

Before starting a recalculation you must modify the parameters. Possible parameters are:

• Calcu Parameters: Calcu No. and Dimension

• all Print Parameters: for additional information in the result printout.

• SIZE Parameters: BG, Wt1, Wt2, etc. (depending on the calculation method) Do not change the Sample No. , this has no influence on the recalculation. A change in the sample No. causes the statistics to be reset!

This function has following steps:Enter the lower sample No. of the titration you want to recalculate. You can recalculate allresults of the current series.If no number is entered the last titration will be recalculated.If you enter a sample No. of a titration which has not been performed, clearly no data exist forthe moisture content.The previous date, size parameter, measurement time, background level and other data, ifnot modified for recalculation, are printed out as before. The printout of a recalculation ismarked by a #.(There is no graphical representation or data table printout for the recalculated results.)

Sample No.S a m p l e N o.? 0 1 - 0 1

Lower Sample No. → Sample No. of the series

Higher Sample No. → Series No.

Functions


6.4 Statistical evaluation of titration series (FUNCTION 2)

With series titrations, the DL37 allows statistical evaluation of the results. The statisticscalculation includes all analyzed samples of a series (maximum 100 samples in a series).The results remain stored even after the statistics calculation.If you change the sample No. or the calcu No. in an activated method, the results memory ofthis method is cleared automatically (= statistics reset).Every method has its own result memory. If you switch to another method, the resultsmemory is not cleared. This allows you to interrupt a series, switch to another method, run atitration, switch back to the previous method and continue the series.With FUNCTION 4 you can delete a single result in a series, for example an outlier. (Seechapter 6.6, Statistics: Deletion of single results in series.)If there are no results in the results memory, “Data Not Exist” is displayed.



2 Auto Statistics Recalculation preset.

ENTER Data Print; off 3 Select whether or not the sample

– Data Print; on 3 No. and moisture content in

memory, as well as the statistics

ENTER calculation results will be printed

Mean moisture concentration

Standard deviation

Coefficient of variance

x = x1+ x2 + ....... +n

n

SD =- xi

n -1

2x( )∑

CVSD 100

%= ⋅ ( )x

Functions


6.5 Statistical evaluation of manually entered data (FUNCTION 3)

With the DL37 you can run a statistical evaluation based on data entered using the keypad.Up to 100 data can be entered to perform a statistical evaluation.

This function has the following steps:You can select the input data unit (µg, mg, %, ppm or no unit)You enter the data and terminate the data entry with PRINT. The result of the statisticalevaluation and all entered data are printed out.After the printout, the data memory is automatically cleared.



3 Manu Statistics

ENTER Dimen; µg ↑ Select input data units (µg, mg, %,ppm, no unit).

– Dimen; mg ↑

– Dimen; % ↑

ENTER Data-01? Enter No. 1 data.

1 . 1 2 3 Data-01? 1.123


1 . 1 1 2 Data-02? 1.112


1 . 1 1 8 Data-03? 1.118

ENTER Data-04? Enter final data. Press PRINT key.

PRINT

Functions


Manual statistics calculation

Mean moisture concentration

Standard deviation

Coefficient of variance

6.6 Statistics: Deletion of single results in a series (FUNCTION 4)

With this function a single result of a series, for example an outlier, which you do not want forthe statistical evaluation, can be deleted. The number of results is less, but the samplenumbering does not change.The DL37 confirms the deletion of a result with the printed message:00-02 Data deleted!If you enter a sample No. having no data in the memory, the message “Data not Exist” will bedisplayed.



4 Data Deletion

ENTER Low Samp No.? 01

2 Low Samp No.? 02 Enter the lower sample No. of the

data to be deleted from the

ENTER statistics calculation data.

x = x1+ x2 + ....... +n

n

SD =- xi

n -1

2x( )∑

CVSD 100

%= ⋅ ( )x

Functions


Deletion of a result in a series:

6.7 Date and time setting (FUNCTION 5)

With this function you can set date and time.



5 Calendar

ENTER YYMMDD? 87.01.01 Enter year, month and day

9 0 0 9 1 7 YYMMDD?90.09.17

ENTER HHMM? 19.56 Enter hour and minute

1 3 3 0 HHMM? 13.30

ENTER

Functions


6.8 RS-232C interfacing (FUNCTION 6)

The DL37 has an RS-232C interface for the connection of a computer or to a printer.(Installation, see APPENDIX A: Schematic Diagram.)With this function you can set the configuration of the RS-232C interfacePossibilities:Baud rate: 110, 150, 300, 600, 1200, 2400, 4800 and 9600Parity: even, odd or no parityStop Bit: 1 or 2Software Handshake: on or offWith Software Handshake off, you can use the Hardware Handshake.



6 Option

ENTER RS-232C Select the RS-232C.

ENTER Baud Rate; 1200 3 Select the baud rate.

– Baud Rate; 2400 3 Choose from 110, 150, 300, 600,

1200, 2400, 4800 and 9600 baud.

– Baud Rate; 4800 3

ENTER Parity; even 3 Select the parity; even parity, oddparity or no parity. none

ENTER Stop Bit; 1 3 Select the stop bit; 1 or 2.

ENTER Soft H. S.; on 3 Select the software handshake;on or off.

If you have connected a computer to the DL37 and installed it, the DL37 is in a position toreceive and process data in a specific format from a source or send to that source.Detailed description of the communication procedure between the DL37 and a computer isdescribed in a special manual. If a GA42 is attached, its dip switch 2 must be set to "on" andthe RS settings in Function 6 toBaud rate: 1200Parity: no parityStop bit: 2

With FUNCTION 6 PRINTyou can print out the RS-232C interface configuration:

Functions


6.9 Display of the polarization potential and the results (FUNCTION 7)

With this function you can displaya) the polarization potential of the electrodeb) all results of a titration series.

Display of the polarization potential of the electrode:This is current, updated display of the polarization potential of the electrode in mV. Thisdisplay can be activated when a titration is in progress.You can cancel this display with ENTER.

Display of series results:You can display the results of a series by entering the lower sample No.If you enter the sample No. and confirm with ENTER, the display flashes (lower sample No.and result).Now you can print out the result with the PRINT function or enter another lower sample No.,for a new display of the result.With a second confirmation with ENTER the result display will be fixed. No additional lowersample No. can now be entered.With an additional ENTER you can cancel this display.It is not possible to display the result of a current titration with this function.



7 Display

ENTER Display; Pot mV 3 Select „Pot mV 3“ to indicate the

polarization potential.

– Display; Data 3 Set „Data 3“ to indicate the result-

display.

ENTER

Low Samp No.? 01 Enter the lower sample No. of theresult to be displayed.

0 5 Low Samp No.? 05 Display flashes.

ENTER Low Samp No.? 05

01-05 0.0240%

0 1 Low Samp No.? 01 Enter the lower sample No. of an

other result to be displayed.

ENTER Low Samp No.? 01 Display flashes.

01-01 0.0238%

PRINT Results now printed out.

Functions


6.10 Purging during DO337 conditioning (FUNCTION 8)

After new installation of the DO337 Drying Oven the oven and the cell must be freed frommoisture. This you can do with a purging program.(Before you use this function connect the DO337 to the DL37.)


FUNCTION F No.; 0-8

8 Oven Purge

ENTER Back; sec? 1800 Back-purging time

ENTER Cell; sec? 600 Cell purging time

ENTER START or RESET Press START key to start the pur-

ging program

START Back purge 1799 The remaining time of Back purge

Cell Purge 599 or Cell purge is displayed

Note

If the START key is pressed without a connected DO337, the error message “Oven Error”will be displayed.

Functions


DO337 Drying Oven:

Carrier gas outTo titration cell Eggplant-shaped sampler

Purge gas discharge valve

Flowmeter

Flow control valveCarrier gas in

Silica gel container

Zeolite container

Heater

Back-purging (purge gas discharge valve: open)

Cell purging (purge gas discharge valve: closed)

21

1

2

Special Keys


7. Special Keys

The DL37 has several special keys. These keys are:

the RESET key interruption of a titration and parameter entry

the – key switch functionthe STIRRER key stirrer switch on/off function

the SPEED key stirrer speed control

the PRINT key printer operation

STIRRER

SPEED

RESET

PRINT

-

FUNCTION

RESULT

SIZE

TITR.PARA

METHOD

1

0

4

7

2

.

5

8

3

6

9

CLEAR

ENTER

7.1 The – Key (the key with the switch function)

1. Switch and cursor function in the parameter settingMany parameters do not require entry of a value but have to be chosen from a given list, forexample:End level on 3 / off 3Start auto 3 / manu 3Wt variable 3 / constant 3Dimension % 3 / ppm 3Graphic off 3 / Form 1 3 / Form 2 3

With the – key you can change these parameters.

General: All parameters with the 3 sign can be changed with the – key.

2. Switch to automatic weight transfer from a connected balanceThe size parameters Wt1, Wt2, Wt0 (sample weight) can be entered manually or by

pressing the – key. The weight will then be transferred from the connected balance.

Special Keys


7.2 The RESET Key

With the RESET key you can interrupt a titration.

If you press the RESET key the titration will immediately be interrupted and the DL37 willreturn to the “ready” or “stable” mode. No results will be calculated or printed; the nexttitration will have the same sample No.

Caution If you have defined End Level “off” (you have defined a titration time limit), a resultwill be calculated with the titrated water until the interruption and the enteredweight; the results are displayed and printed out.There is thus a possibility to terminate a titration before the defined time limit isreached.

With the RESET key you can quit the parameter entry.If you want to change only the first parameter of a parameter list, you can quit the parameterlist with the RESET key after you have changed the parameter.

You can not interrupt a printout with the RESET key.

Caution If you change the parameters during a titration, a RESET causes a termination ofthe titration!

7.3 The STIRRER and SPEED Keys

With the STIRRER and SPEED keys you can control the magnet stirrer in the titration vessel.

With the STIRRER key you can switch the magnetic stirrer on and off. This functiongenerates no response on the display and must not be confirmed with ENTER.For example: If you press the STIRRER key while the stirrer is running, it will be stopped; ifyou press the STIRRER key again, the stirrer will start again.

With the SPEED key you can set the speed of the magnetic stirrer. You can choose a stirrerspeed from 0 to 9 (0 stops the stirrer). For a titration under normal conditions use stirrerspeed 4 - 6.


SPEED Stirrer speed? 3 The stirrer runs with speed 3

4 Stirrer speed? 4 The stirrer runs with speed 4

5 Stirrer speed? 5 The stirrer runs with speed 5

ENTER

Special Keys


7.4 The PRINT Key

With the PRINT key you can print out all method parameters and all function parameters; youcan also start a paper advance by 7 lines.All printing functions can be done when a titration is in progress.

Entry key Description

PRINT Paper advances by 7 lines

METHOD PRINT Printout of all method parameters

(titration, calculation, print, data list andsize parameters).

TITR.PARA PRINT Printout of the titration parameters.

RESULT PRINT Printout of the calculation, print and

data list parameters.

RESULT Press – key, display "Calcu Para 3 " Printout of the calculation parameters

then ENTER and then PRINT (parameters for the result calculation).

RESULT Press – key, display "Print Para 3 " Printout of the print parameters

then ENTER and then PRINT (parameters for the result).

RESULT Press – key, display "Data list Para 3 " Printout of the graphics and the result of

then ENTER and then PRINT the last titration.

SIZE PRINT Printout of the size parameters

(parameters for the samples).

Special Keys


Entry key Description

FUNCTION 0 PRINT Printout of the Reagent life parameters

(Life and Alarm limit for anolyte andcatolyte).

FUNCTION 1 PRINT Printout of the results of the last

recalculation (see chapter 6.3).

FUNCTION 2 PRINT Printout of the statistics of the running

series (see chapter 6.4).

FUNCTION 5 PRINT Printout of date and time.

FUNCTION 6 PRINT Printout of the RS-232C interface

configuration (see chapter 6.8).

FUNCTION 8 PRINT Printout of the DO337 purging

parameters (see chapter 6.10).

7.5 Instrument identification

On delivery of the DL37, its correct identification is stored (see model plate at the rear); itappears on every GLP report. You can change the identification.

Key selection Display/Entry (example) Description

Method [1-5] 70 "Instr ID" flashes in the display.

Enter, e.g. "UBX67401": Press the "–" -key repeatedlyU until U appears.

UB Press the "–"- key repeatedly until B appears.

UBX Press the "."- key etc.You can enter maximum 8 characters.

••

METHOD

ENTER

ENTER

ENTER

Maintenance


8. Maintenance

8.1 Charging of memory backup battery

The memory backup battery is fully charged by keeping the power supplyswitched on for 50 or more hours. The fully charged battery operates forabout a month (memory backup function) even if the power supply is off.Once the battery is fully charged, it suffices to leave the power supply on forapprox. 30 minutes a day to keep the battery operative.

Note: If the battery needs to be replaced, contact METTLER TOLEDO ser-vice.

8.2 Application of grease

Apply silicon grease over the glass contact areas. Turn the parts approximately once a weekto ensure they rotate smoothly; if not, apply a thin coating of grease. Parts may otherwisestick and be difficult to separate. Do not apply too much grease as it may penetrate thetitration cell and increase the background owing to the water content of the grease.

8.3 Septum replacement

Change the syringe inlet port septum occasionally. An old septum is easily broken andallows air to enter the titration cell thereby increasing the background.

8.4 Silica gel replacement

Replace the desiccator silica gel from time to time. When the silica gel in the drying tubes ofthe titration vessel becomes pink, its hygroscopic properties are impaired and it must bereplaced immediately. Also apply silicon grease over the contact areas of the titration celldesiccator.

8.5 Long-term storage measures

It is advisable to clean and dry the titration cell and keep it disassembled in a desiccator. Forcleaning and drying details, see chapter 8.9.

Maintenance


8.6 Catholyte replacement

Do not inhale or allow skin contact of Karl Fischer reagents! They arepotentially hazardous.Perform replacement in a fume hood!Never pour reagents down the drain!

Inject about 5 mL of catholyte.

Note: Adjust the catholyte level to the “100” mark on the titration cell.

Replace the catholyte in the following cases:

• when the reagent life (mg H2O) has reached 200 mg H

2O as indicated by function “0”

command,

• when the background level is excessive,

• one week after replacement of a reagent.

Periodic catholyte replacement is important. Otherwise the background level will increaseand the membrane could become contaminated with foreign matter causing measurementerrors.

Note: After replacement, select FUNCTION 0, enter “0” up to “C. Life”. The accumulatedelectrolytic current (moisture-converted) of catholyte is set to zero. (See page 56.)

8.7 Anolyte replacement

Inject about 100 mL of anolyte.

Note: Add 20 mL of ethylene glycol when measuring vaporized moisture or gaseoussamples.

Replace the anolyte in the following cases:

• when the reagent life (mg H2O) has reached 1000 mg H

2O as indicated using function 0 “A.

Life”,

• if the liquid (with added sample) in the titration cell has exceeded the level mark “150”, thediluted anolyte will cause poor sensitivity and extended measurement time,

• when the background level becomes too high.

Note: After the replacement, enter 0 in FUNCTION 0 “A. Life” to delete the accumulatedelectrolytic current (moisture-converted) of anolyte (reagent life). (See page 56.)

WARNING

Maintenance


8.8 Cleaning detection electrode

When sample impurities have adhered to the platinum pins of the electrode, first wash withconcentrated nitric acid or carbon tetrachloride, then with methanol.

8.9 Cleaning inner burette

8.9.1 Cleaning steps

(1) Clean using alcohol• Press the PRE-TITR key to “off”.

The “Pre-Titr” display flashes.• Remove the inner burette from the titration cell and drain the catholyte.• Remove grease from contact areas with methanol.• Inject methanol into the cathode of the inner burette two or three times, then inject

about 10 mL of methanol. Place the inner burette in a beaker.• Add methanol to the beaker until it reaches the methanol level in the cathode. Let

stand for about 30 minutes.• Follow the Drying Instructions below.

(2) Clean using chromic acid (when foreign matter has built up on the membrane and theplatinum surface).

• Use chromic acid instead of methanol in the steps above. Let stand overnight.• Drain the liquid out of the cathode. Repeat 5 or 6 times: Wash the cathode with pure

water until the yellowish color disappears. (Rinse the chromic acid off the membrane.)• Follow the Drying Instructions below.

Note: Chromic acid cleaning dissolution. Prepare by dissolving about 1.5 g of potas-sium dichromate in 100 mL of sulfuric acid.

Maintenance


8.9.2 Drying steps

(1) Warm air drying with a hair dryer

Operating Instructions METTLER TOLEDO DL37 KF Coulometer · 2. Introduction 6 2.1 Measurement...

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Transcript of Operating Instructions METTLER TOLEDO DL37 KF Coulometer · 2. Introduction 6 2.1 Measurement...