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PLOT Column Selection(or How to Retain Your Gases)

Telephone Number: 816-650-0621Chair Person: Lisa Lloyd

Allen K. VickersApplications Engineer ManagerDecember 6, 2000

Dial 1-816-650-0621 for e-Seminar Audio

WCOT vs. PLOT

Type

WCOT

PLOT

Stationary Phase

Liquid orgum

Solid

ChromatographicProcess

Gas / Liquidpartition

Gas solidadsorption

Stationary Phases

PolysiloxanesPEG

Porous Polymers,Al2O3,

Zeolites, etc.


Why Use PLOT Columns?

• Enhanced retention

• Enhanced selectivity

• Permit higher initial oven temperatures than WCOT


PLOT Columns

"Solid"PorousLayer

Fused Silica Tubing

Ideal for the analysis of gases due totheir increased retention (k) and uniqueselectivity (α) compared to WCOT


WCOT Ethylene Analysis


PLOT Ethylene Analysis


Selectivity Interactions in PLOT Phases

Shape / Size Surface

Zeolites Al2O3

Porous Polymers

Bonded Carbon Bonded SilicaMolecular Sieves


J&W / Agilent PLOT Columns

• GS-Alumina

• HP-PLOT Al2O3 “M”

• HP-PLOT Al2O3 “S”

• HP-PLOT Al2O3 “KCl”

• HP-PLOT MoleSieve

• GS-CarbonPLOT

• HP-PLOT Q

• HP-PLOT U

• GS-GasPro


Al2O3 PLOT Columns

• GS-Alumina

• HP-PLOT Al2O3 “M”

• HP-PLOT Al2O3 “S”

• HP-PLOT Al2O3 “KCl”

•Different "polarities" due to different salt deactivation treatments


Surface Interactions in PLOT Columns

• Vapor pressure always plays a leading role in solute interactions

Gas Flow δ- δ- δ+δ+

neutral

+ + + + + + + + + + + + ++ + + + + + + + + + + + +


Propylene Impurities


Crude 1,3-Butadiene


Extended HC Mixture


Al2O3 PLOT Column Dimensions Available

• “M”, “S” and “KCl”

• all available in 0.25, 0.32 and 0.53 mm ID

• 15, 30 and 50 meter lengths (depending onID)

• GS-Alumina

• available in 0.53 mm ID

• 15, 30 and 50 meter lengths


0.25 mm ID PLOT Al2O3 “S”


Al2O3 Column Considerations

• Will adsorb water and CO2, affecting retention and resolution.

• Recondition at 200°C to restore performance.

• Not recommended for analysis of “polar” compounds such as alcohols,sulfurs, ketones, etc.

• Upper temperature limit of 200ºC


Break Number 1

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Molecular Sieve PLOT Columns

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Zeolite "Backbone"

Size Selectivity


Molecular Sieve PLOT Columns

• 5Å zeolite for the analysis of fixed and permanent gases:

H2, O2, N2, CO, CH4

He, Ne, Ar, Kr, Xe

SF6


Permanent Gases


Noble Gases


Sulfur Hexafluoride


HP-PLOT MoleSieve

• 0.32 and 0.53 mm ID

• 15 and 30 meter lengths

• Both thin and thick films available

• Choose thin film for standard permanent gas analysis

• Choose thick film for resolution of argon from oxygen at 35ºC

• Upper temperature limit of 350ºC


Molecular Sieve Column Considerations

• Very high retention stationary phase

• Can be easily fouled by high MW hydrocarbons and polarcompounds

• Use pre-column or backflush if necessary

• Will adsorb water and CO2

• Columns can be reconditioned by holding at elevatedtemperature (350ºC) for several hours


GS-CarbonPLOT

• Monolithic carbon layer

• Unique selectivity

• Phase formed in situ

• No particle generation

• Extended temperature limit of 360ºC

• Not affected by water


GS-CarbonPLOT Applications

• Light hydrocarbons (C1-C5)

• Synthesis Gas

• H2, CO, CO2, CH4, N2/O2, H2O

• Trace CO, CO2 and acetylene in ethylene streams (simplification ofASTM D2505)

• Great resolution of air, CO, CO2 and C1-C2 hydrocarbon isomers

• Light solvents


C1 to C3 Hydrocarbons

0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50

1. Methane2. Acetylene3. Ethylene4. Ethane5. Propyne6. Propylene7. Propane

GS-CarbonPLOT30 m x 0.32 mm I.D., 1.5 µmCarrier: He @ 30 cm/sOven: 125°C for 2 min 125°C to 225°C at 20°/minInjector: Split 1:20, 250°CDetector: MSD, SIM

1

2

34

56

7


Natural Gas Mixture

1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 9.00 10.00 11.00 12.00

1. Methane2. Acetylene3. Propane4. iso-Butane5. n-Butane6. iso-Pentane7. n-Pentane


1 2

3

4

5

6

7

0

Dial 1-816-650-0621 for e-Seminar Audio&��

Column: GS-CarbonPLOT 30 m x 0.32 mm I.D. x 3.0 µmJ&W P/N: 113-3133Carrier: Helium at 27 cm/sec (calculated off N2 at 35°C)Oven: 35°C isothermalInjector: 185°C, 1:30 split, 250 µL injection volumeDetector: TCD, 150°C

1. Nitrogen and Oxygen (5% each)2. Carbon monoxide (5%)3. Methane (4%)4. Carbon dioxide (5%)

Permanent Gases

5 2.0 2.5 3.0 3.5 4.0

1

2

4

3


Solvents

6.00 7.00 8.00 9.00 10.00 11.00 12.00 13.00

1. Methylene Chloride 2. Acetone 3. Carbon Disulfide 4. Ethyl Ether 5. Ethyl Acetate 6. Benzene


1

2

3

4

5

6


GS-CarbonPLOT

• 0.32 and 0.53 mm ID

• 15, 30 and 60 meters

• 0.32 mm ID available in thin and thick film

• Upper temperature limit of 350º/360ºC


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Porous Polymer Phases

• Retention is a combination of size and surface interactionsbetween the analyte and the porous solid phase.

• The polymers are generally homopolymers of divinylbenzeneand divinyl-styrene.

• N, R, Q, T, U phases


Agilent Porous Polymer PLOT Columns

• HP PLOT-Q

• Bonded polystyrene-divinylbenzene

• HP PLOT-U

• Bonded divinylbenzene/ethylene glycol dimethacrylate

• More polar than “Q”


Natural Gas on HP-PLOT Q


HP-PLOT QVolatile Solvents


HP-PLOT QConsecutive runs for up to 200 headspace injections of alcoholmixture. Excellent stability!!


HP-PLOT QAfter 150 consecutive direct water injections


HP-PLOT UVolatile Solvents


HP-PLOT UImpurities in Acetic Acid


HP-PLOT UVolatile Primary Amines


Porous Polymer Column Dimensions Available

• Both HP-PLOT Q and HP-PLOT U:

• 0.32 and 0.53 mm ID

• 15 and 30 meter lengths


GS-GasPro

• Silica-based PLOT column

• Bonded stationary phase

• Unique selectivity

• Highly inert to reactive compounds

• Retention stability unaffected by water


GS-GasPro

• Upper temperature limit of 260º/300ºC

• No particle generation

• Applications

• CO, CO2

• C1 to C12 hydrocarbons

• trace sulfur analysis

• hydrides (arsine, phosphine, germane, etc.)

• halocarbons

• HCl, NH3


GS-GasPro Dimensions Available

• Currently only available in 0.32 mm ID

• 5, 15, 30 and 60 meter lengths


Considerations for PLOTColumn Analysis

• Inlet issues• split versus direct injection• gas sampling valves• low dead volume• column ID and flow rate

• Detector issues• particle generation or “spiking”; particle traps• column ID and flow rate


Considerations for PLOTColumn Analysis

• Column issues• selectivity• capacity; overloaded peaks• inertness• temperature limits

• Column contamination• efficiency loss; “ghost peaks”; increase in bleed• water, CO2, high molecular weight hydrocarbons?•Carrier gas purifiers


Wrap-up E-Seminar Questions

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