a new pid for trace analysis pc2010a

PittconPittcon Feb, 28, 2010, Orlando, FLFeb, 28, 2010, Orlando, FL

Dr. Jack DriscollPID Analyzers LLCPID Analyzers, LLC

Paper # 180-5Session 180 - GC Detectors

2/1/2010 PID Analyzers, LLC Copyright 2010 www.pid.bz

The first commercial PID was introduced at Pittcon in 1976 by HNU Systems. This detector was found to be 50 x more sensitive than the FID

This detector has gone through several redesigns since then and has found a niche in environmental and trace analysis with more than 15,000 units sold

A fourth generation PID has been developed that has improved noise characteristics in the lamp circuit and in the electrometer. The high voltage circuit employs a Cockcroft Walton multiplier and uses a constant current source instead of a constant voltage d i th t d i PID’ Thi h lt d i 20design that was used previous PID’s. This has resulted in a 20-30% reduction in the background noise level and allowed us to achieve sub pg detection levels for aromatic compounds.

2/1/2010 PID Analyzers, LLC Copyright 2010

1976Ion chamber:

2010I h bIon chamber:

teflonMax T; 200CDead vol: 500 uLSensitivity: 10 pgb

Ion chamber:ceramic/gold

Max T; 275CDead vol: 100 uLSensitivity: 1 pg

benzeneTemp cont: variac

benzeneTemp cont: digitalproportional

PI52 ELECTROMETER CONTROLSPI52 ELECTROMETER CONTROLS

Input Att’n x1, x10 Output Att’n x1 x10 Output Att n x1, x10,

x100 Autozero Proportional T Control Lamp on/off LCD Temp set or LCD-Temp set or

Detector output Fine Gain pot


R + h = R + + e-

ProcessProcess

R + h = R + e

where

R= molecule h = a photon with an p energy > IP of R R+ = positive ion e- = electron e = electron


PID COMPONENTSPID COMPONENTS

LAMPION CHAMBER ION CHAMBER

HV FOR LAMP BIAS FOR ION BIAS FOR ION

CHAMBER HEATER THERMOCOUPLE


Linear dynamic range > 5 x107

Detection limit <0.5 ppb benzene Non destructive; other detectors can be run in-series Sensitivity increases as the carbon number increases (carbon

counter)counter) For 10.2 eV lamp, responds to carbon aliphatic compounds >

C4, all olefins and all aromatics The PID also responds to inorganic compounds such as H2S, p g p 2 ,

NH3, Br2, I2, PH3, AsH3, e.g. any compound with an ionization potential of < 10.6 eV

The PID is more sensitive than the FID; >200 x more sensitive for aromatics 80 times for olefins & 30 times for alkanes > C6for aromatics, 80 times for olefins, & 30 times for alkanes > C6

Non destructive detector; other detectors can be run downstream

Concentration sensitive detector


More compact size p Reduced lamp noise level Reduced electrometer noise with

improved design and IC’sp o ed des g a d C s Reduced dead volume of detector Digital temperature control

Optional USB ADC PC Control PeakWorks chromatography software PeakWorks chromatography software Operates with a Web PC


PID PID 10.6 10.6 eVeV


BTEX with BTEX with PeakWorksPeakWorks ChromatographChromatography Software

5 b5 b BTEXBTEX5 ppb 5 ppb BTEXBTEX


Detector Benzene 5 ppb Benzene 50 ppb1 CV = 9.99 % @ 4.9 ppb CV = 2.37 % @ 48.5 ppb

2 CV = 3.2 % @ 4.73 ppb CV = 1.37 %@ 47.4 ppb

3 CV = 13.7 % @ 4.7 ppb CV = 0.76 % @ 49.6 ppb

4 CV = 13.7 % @ 4.7 ppb CV = 0.69 % @ 50.3 ppb

5 CV = 18.4 % @ 5 ppb CV = 1.82 % @ 50 ppb

Avg 5 ppb =11.8 Avg 50 ppb = 1.40

Ethyl Benzene 5 ppb Ethyl Benzene 50 ppb

1 CV = 16.4 @ 5.0 ppb CV = 1.35% @ 48.5 ppb

2 CV = 5.9 @ 4.5 ppb CV = 1.7% @ 47.44 ppb

3 CV = 17.5 @ 4.37 ppb CV = 2.74% @ 49.46 ppb

4 CV = 14.5 @ 4.2 ppb CV = 3.2% @ 50.2 ppb

5 CV = 43.1 % @ 2.7 ppb CV = 3.7 % @ 47.4 ppb

Avg 5 ppb = 13.50 Avg 50 ppb = 2.44

Note: Each set of data is 5 runs


Photoionization DetectorPhotoionization Detector Photoionization DetectorPhotoionization Detector 1st commercial introduction in 1976 by

HNU (Driscoll)- 50x more sensitive than FID for aromatics low ppbFID for aromatics- low ppb

Far UV Absorbance DetectorFar UV Absorbance Detector 1st commercial introduction in 1985 by 1 commercial introduction in 1985 by

HNU (Driscoll)-low ppm sensitivity-nearly universal response

Flame Ionization DetectorFlame Ionization Detector Flame Ionization DetectorFlame Ionization Detector 1st commercial introduction in late 1950s-

(ICI ) hydrocarbons- sub ppmy


Detectors and CharacteristicsPIDPID FUVFUV FIDFID

SpeciesSpeciesC1C1--C4 alkanesC4 alkanes NN YY YYC5+ alkanesC5+ alkanes YY YY YYAlkenesAlkenes YY YY YYAromaticsAromatics YY YY YY

Dynamic RangeDynamic Range 5 x 10exp75 x 10exp7 1 x 10exp51 x 10exp5 1 x 10exp61 x 10exp6

Detection LimitsDetection LimitsAirAirAirAir

aromaticsaromatics < 0.5 ppb< 0.5 ppb 500 ppb500 ppb 5050--100 ppb100 ppbalkenesalkenes <5 ppb<5 ppb 500 ppb500 ppb 5050--100 ppb100 ppbalkanesalkanes < 10 ppb< 10 ppb 500 ppb500 ppb 5050--100 ppb100 ppbalkanesalkanes < 10 ppb< 10 ppb 500 ppb500 ppb 5050--100 ppb100 ppb

WaterWateraromaticsaromatics < 0.1 ppb< 0.1 ppb 10 ppb10 ppb 2.52.5--10 ppb10 ppbalkenesalkenes 0 1 ppb0 1 ppb 10 ppb10 ppb 2 52 5 10 ppb10 ppbalkenesalkenes 0.1 ppb0.1 ppb 10 ppb10 ppb 2.52.5--10 ppb10 ppbalkanesalkanes 1 ppb1 ppb 10 ppb10 ppb 2.52.5--10 ppb10 ppb


If a GC detector does not destroy the sample, If a GC detector does not destroy the sample, then a second detector can be run in-series. The advantage is that additional confirmation can be obtained during a single run. A number of EPA methods specify dual d t t f l t fi ti S detectors for analyte confirmation. Some non-destructive detectors are:

PID PID FUV

TCD TCD


PIDPID-- FIDFID- identification of aromatics, alkanes & alkenes as a result of the alkanes & alkenes as a result of the differential response

PIDPID--FPDFPD- Total HC and ID of S or P compounds in the mixture

PIDPID--FUVFUV- wider HC response (low MW HC & Cl HC) d i f th f & Cl-HC) and expansion of the range of compounds detected in low ppmTCDTCD i l d t t ( t %) d TCDTCD- universal detector ( ppm to %)- and expansion of the range of compounds detected in high ppmg pp


FUV/PID 11.7In-series


PID/FIDll lIn parallel


We have shown that the new 4th We have shown that the new 4generation PID Is the most sensitive detector for VOC’s Has improved sensitivity Is more compact and versatile Can be combined with other GC

detectors to improve the range of compounds detected & help identify compounds detected & help identify unknowns


a new pid for trace analysis pc2010a

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