J.N. Driscoll, PID Analyzers,J.N. Driscoll, PID Analyzers,D. Lewis, R. Kipp, Julie Ann, Heidi Hu, D. Lewis, R. Kipp, Julie Ann, Heidi Hu,

Chemistry Dept., Suffolk University Chemistry Dept., Suffolk University Chemistry Dept., Suffolk University Chemistry Dept., Suffolk University

Pittsburg Conference 2006Pittsburg Conference 2006

1

Orlando, FLOrlando, FL

Many of the municipal laboratories that will be Many of the municipal laboratories that will be Many of the municipal laboratories that will be Many of the municipal laboratories that will be required by EPA to monitor As in drinking water are required by EPA to monitor As in drinking water are smallsmall

Traditional methods that have been used to detect ppb Traditional methods that have been used to detect ppb ad t o a et ods t at ave bee used to detect ppb ad t o a et ods t at ave bee used to detect ppb levels of As in water include: AA, ICP, ICPlevels of As in water include: AA, ICP, ICP--MS… MS…

There is a definite need for simpler and less costly There is a definite need for simpler and less costly techniques for the water labs to keep the water rates techniques for the water labs to keep the water rates q pq pfrom rising significantlyfrom rising significantly

We will evaluate two new methods for the detection of We will evaluate two new methods for the detection of ppb levels of As in water; both are simpler and less ppb levels of As in water; both are simpler and less pp ppp pcostly than the spectroscopic methods described abovecostly than the spectroscopic methods described above

These methods are: photoionization (PID) and These methods are: photoionization (PID) and electrochemistry (ECD) detectorselectrochemistry (ECD) detectors

2

Determine the detection limits and linear range gfor both the PID and ECD

Simplify the equipment (electronics) needed f d ifor detection

Evaluate a manual and automated method for the determination of Asthe determination of As

Determine the best method for quantitation of the method: peak height, integrated peak area, p g , g p ,headspace (PH) …

3

Food Food –– 70%; Fish70%; Fish Food Food 70%; Fish70%; Fish TypeType-- organic (less toxic)organic (less toxic)

Water 29%Water 29%%% TypeType-- mixturemixture

Air Air –– 1%1% Cigarettes Cigarettes

Type mixture/resultType mixture/result-- lung cancer lung cancer yp /yp / gg

4

1. Aqueous sample (containing AsAqueous sample (containing As+3+3) is injected ) is injected into hydride generatorinto hydride generator

AsAs+3+3(aq) (aq) As HAs H33(g) (g) in the presence of reducing agent (NaBHin the presence of reducing agent (NaBH44 + HCl)+ HCl)

2. The AsH2. The AsH33(g) produced is swept into the (g) produced is swept into the analyzer with nitrogenanalyzer with nitrogeny gy g

AsHAsH33 (g) + hv (g) + hv AsHAsH33+ e+ e--

3 The AsH3 The AsH produced is proportional to the produced is proportional to the 3. The AsH3. The AsH3 3 produced is proportional to the produced is proportional to the arsenic concentration in the water samplearsenic concentration in the water sample

5

4. Analysis via a Photoionization Detector oror 4. Analysis via a Photoionization Detector oror 5. Analysis via an Electrochemical Detector 6 Detection by headspace method with peak 6. Detection by headspace method with peak

detection oror 7. Detection by PeakWorks Data Software 7. Detection by PeakWorks Data Software

6

The equipment for arsenic determination includes: A hydride generator that contains a reducing agent A carrier gas such as perpurified nitrogen with an in-line flow

controller A glass wool filter (in-line) for moisture

A high input impedence preamplifier for the PID; a preamp for the electrochemical detector

A photoionization detector with a 10.6 eV lamp or an electrochemical detector for arsine

A 16 bit ADC smart meter that integrates the signal and di l h l 2 li 16 h LCD di ldisplays the results on a 2 line x 16 character LCD display

A PC with windows XP & PeakWorks software

7

8

9

10

Calibration Curve As in Water- PID

y = 29.427x - 25.0181500

2000

g R2 = 0.9983

500

1000

1500

3 R

eadi

ng

0

500

0 10 20 30 40 50 60

AsH

3

-5000 10 20 30 40 50 60

ug/L As in water

11

Calibration Curve As in Water- ECD

y = 3 1782x + 3 2148200

r y = 3.1782x + 3.2148R2 = 0.9971

100

150

L A

s in

Wat

er

0

50

0 10 20 30 40 50 60

ug/L

AsH3 Reading

12

PID PID20 ug/L +/- 16.9%

50 ug/L +/- 5.3%g/ / %

ECD ECD 30 ug/L +/- 24.6% 60 ug/L +/- 8 2% 60 ug/L +/- 8.2%

13

Type Det. Limit (ug/L) Cost $Type Det. Limit (ug/L) Cost $ Type Det. Limit (ug/L) Cost $Type Det. Limit (ug/L) Cost $ICP-MS 1.4 200,000ICP-AES 8 80 000ICP AES 8 80,000GFAA 0.5 80,000GHAA 0 5 60 000GHAA 0.5 60,000ASV 1.0 30,000PID 2 12 000PID 2 12,000ECD 10 9,000

14

The PID is an ideal detector for ppb (down to The PID is an ideal detector for ppb (down to 2) levels of As in water. The electronics and the method are simpler than any of the complex spectroscopic methods. The cost of the PID is a fraction of the cost of an AA

The ECD will detection As down to 10 ppb levels in water. The cost of this detection systems is also a fraction of the cost of an AAsystems is also a fraction of the cost of an AA

15