A New Pid For Trace Analysis Pc2010a

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A New Pid For Trace Analysis Pc2010a

  1. 1. Pittcon Feb, 28, 2010, Orlando, FL Dr. Jack Driscoll PID Analyzers LLC Analyzers, Paper # 180-5 Session 180 - GC Detectors 2/1/2010 PID Analyzers, LLC Copyright 2010 www.pid.bz
  2. 2.  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 design that d i th t was used previous PID’ Thi has resulted in a 20- d i PID’s. This h lt d i 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
  3. 3. 2/1/2010 PID Analyzers, LLC Copyright 2010
  4. 4. 1976 2010 Ion chamber: Ion h b I chamber: teflon ceramic/gold Max T; 200C Max T; 275C Dead vol: 500 uL Dead vol: 100 uL Sensitivity: 10 pg Sensitivity: 1 pg benzene b benzene Temp cont: variac Temp cont: digital proportional
  5. 5. PI52 ELECTROMETER CONTROLS  Input Att’n x1, x10  Output Att’n x1 x10 Att n x1, x10, x100  Autozero  Proportional T Control  Lamp on/off  LCD-Temp LCD Temp set or Detector output  Fine Gain pot 2/1/2010 PID Analyzers, LLC Copyright 2010
  6. 6. Process  R + h = R + + e-  where   R= molecule  h = a photon with an p  energy > IP of R  R+ = positive ion  e- = electron 2/1/2010 PID Analyzers, LLC Copyright 2010
  7. 7. PID COMPONENTS  LAMP  ION CHAMBER  HV FOR LAMP  BIAS FOR ION CHAMBER  HEATER  THERMOCOUPLE 2/1/2010 PID Analyzers, LLC Copyright 2010
  8. 8.  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)  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 , 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 > C6 aromatics olefins,  Non destructive detector; other detectors can be run downstream  Concentration sensitive detector 2/1/2010 PID Analyzers, LLC Copyright 2010
  9. 9.  p More compact size  Reduced lamp noise level  Reduced electrometer noise with improved design and IC’s p o ed des g a d C s  Reduced dead volume of detector  Digital temperature control  Optional USB ADC  PC Control  PeakWorks chromatography software  Operates with a Web PC  2/1/2010 PID Analyzers, LLC Copyright 2010
  10. 10. 2/1/2010 PID Analyzers, LLC Copyright 2010
  11. 11. 2/1/2010 PID Analyzers, LLC Copyright 2010
  12. 12. PID 10.6 eV 2/1/2010 PID Analyzers, LLC Copyright 2010
  13. 13. BTEX with PeakWorks Chromatograph Software Chromatography 5 ppb BTEX b 2/1/2010 PID Analyzers, LLC Copyright 2010
  14. 14. Detector Benzene 5 ppb Benzene 50 ppb 1 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 2/1/2010 PID Analyzers, LLC Copyright 2010
  15. 15. 2/1/2010 PID Analyzers, LLC Copyright 2010
  16. 16.  Photoionization Detector  1st commercial introduction in 1976 by HNU (Driscoll)- 50x more sensitive than FID for aromatics low ppb aromatics-  Far UV Absorbance Detector  1st commercial introduction in 1985 by HNU (Driscoll)-low ppm sensitivity- nearly universal response  Flame Ionization Detector  1st commercial introduction in late 1950s- (ICI ) hydrocarbons- sub ppm y 2/1/2010 PID Analyzers, LLC Copyright 2010
  17. 17. Detectors and Characteristics PID FUV FID Species C1-C4 alkanes C1- N Y Y C5+ alkanes Y Y Y Alkenes Y Y Y Aromatics Y Y Y Dynamic Range 5 x 10exp7 1 x 10exp5 1 x 10exp6 Detection Limits Air aromatics < 0.5 ppb 500 ppb 50-100 ppb 50- alkenes <5 ppb 500 ppb 50-100 ppb 50- alkanes < 10 ppb 500 ppb 50-100 ppb 50- Water aromatics < 0.1 ppb 10 ppb 2.5-10 ppb 2.5- alkenes 0.1 ppb 01 10 ppb 2.5-10 ppb 2 5- 2.5 alkanes 1 ppb 10 ppb 2.5-10 ppb 2.5- 2/1/2010 PID Analyzers, LLC Copyright 2010
  18. 18.  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 detectors for analyte confirmation. S d t t f l t fi ti Some non- destructive detectors are:  PID  FUV  TCD 2/1/2010 PID Analyzers, LLC Copyright 2010
  19. 19.  PID- FID- identification of aromatics, PID- FID alkanes & alkenes as a result of the differential response  PID-FPD Total HC and ID of S or P PID-FPD- compounds in the mixture  PID-FUV wider HC response (low MW HC PID-FUV- & Cl HC) and expansion of the range of Cl-HC) d i f th f compounds detected in low ppm  TCD- i TCD universal d t t ( ppm t %)- and l detector to %) d expansion of the range of compounds detected in high ppm g pp 2/1/2010 PID Analyzers, LLC Copyright 2010
  20. 20. FUV/PID 11.7 In-series 2/1/2010 PID Analyzers, LLC Copyright 2010
  21. 21. PID/FID In parallel ll l 2/1/2010 PID Analyzers, LLC Copyright 2010
  22. 22.  We have shown that the new 4th generation 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 unknowns 2/1/2010 PID Analyzers, LLC Copyright 2010

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