Detection of polychlorinated biphenyls (PCBs) by Gas Chromatography related techniques

1. Detection of polychlorinated biphenyls (PCBs) by Gas Chromatography related techniques NuwanBalapitiya Literature Seminar Louisiana State University Oct 26, 2009

2. Objective Application of Gas Chromatography related techniques to quantify PCBs in two different real world samples • Solid waste samples • Human serum samples

3. Why PCBs are studied? Many industrial applications Man-made Persistant organic pollutants http://www.americanchronicle.com/articlePics/article33209.gif n n Bioaccumulation Toxicological effects on animals and humans Banned in US 1979 Global ban 2001 http://www.skylercgull.com/images/Cartoon_Characters_22.gif http://www.topnews.in/files/Red-Cross101.png

4. Toxicity Operation of the Prior Informed Consent Procedure for Banned or Severely Restricted Chemicals in International Trade; Decision Guidance Documents, Polychlorinated Biphenyls; Food and Agriculture Organization of the United Nations, United Nations Environment Programme, Rome – Geneva 1992

5. Structure of PCBs • PCBs are molecules composed of two benzene rings with 1 – 10 chlorine atoms attached to them PCB-166 PCB-28 n n PCB-209

6. General protocol for PCB detection • Extraction • Soxhlet extraction • Solvent Extraction • Solid Phase Extraction • Separation • High Performance Liquid Chromatography • Gas Chromatography • Detection • Electron Capture Detector • Mass spectrometry

7. PCBs detection Mass Spectrometry Electron Capture Detector

8. Solid phase extraction (SPE) • SPE is a sample preparation, purification and pre-concentration technique used with liquid samples • Extract volatile and non-volatile analytes • Used with LC and GC • Disposable, pre-packed cartridges are available as columns • Reverse phase (non-polar) • Normal phase (polar) • Ion exchange http://www.sigmaaldrich.com/Graphics/Supelco/objects/4600/4538.pdf

9. SPE process Conditioning Inject sample Elution http://www.sigmaaldrich.com/Graphics/Supelco/objects/4600/4538.pdf

10. Gas Chromatography (GC) • GC is used to separate volatile and thermally stable compounds • Mobile phase is an inert gas (N2, He) • Stationary phase is either a solid (GSC) or a liquid-like polymer (GLC) • Stationary phase is coated inside a capillary column (Open tubular columns) http://www.cseindia.org/html/lab/int_gc.jpg

11. GC Instrument http://teaching.shu.ac.uk/hwb/chemistry/tutorials/chrom/gaschrm.htm

12. Electron Capture Detector (ECD) Carrier gas + Sample inlet Make-up gas inlet (N2) 63Ni Foil http://www.srigc.com/ECDman.pdf

13. Mass Spectrometry (MS) “MS is an analytical technique that measures the molecular masses of individual compounds and atoms precisely by converting them into charged ions” * • Structure of the molecule can be deduced • Used as a quantification method couple with HPLC and GC http://www.chemguide.co.uk/analysis/masspec/masspec.GIF *Dass, C. (2007). Fundamentals of contemporary mass spectrometry. Hoboken, NJ, John Wiley & Sons, Inc.

14. Selected ion monitoring (SIM) • Ion current from one or few selected ions are recorded • The ion with the highest abundance is selected (molecular ion most of the time) • Gives a significant improvement in detection sensitivity (1000 fold gain) • Faster detection because only one or several peaks are detecting (not the total ion chromatogram) Dass, C. (2007). Fundamentals of contemporary mass spectrometry. Hoboken, NJ, John Wiley & Sons, Inc.

15. Internal Standard • A known amount of a compound, different from the analyte, added to the unknown • Internal Standard, • should elute near the peaks of interest • peaks should be well resolved from the analyte peaks • should be chemically similar to analytes of interest • should not react with any sample components • must be available in pure form • PCB-166, PCB-58 and PCB-186 Miller, J.M.(2005). Chromatography: Concepts and Contrasts. Hoboken, NJ, John Wiley & Sons, Inc.

16. Online Coupling of Bead Injection Lab-On-Valve Analysis to Gas Chromatography: Application to the Determination of Trace Levels of Polychlorinated Biphenyls in Solid Waste LeachatesAnal. Chem. 2009, 81, 4822 – 4830 Jose Quintana, WarunyaBoonjob, Manuel Miro*, Victor Cerda** *University of Santiago de Compostela, Spain ** University of Belaric Islands, Spain

17. Experiment • Three solvents were tested for the elution of PCBs (isooctane, toluene and ethyl acetate) • Ethyl acetate was selected as the best solvent, which gives more than 80 % after one elution • Four different reversed-phase sorbent materials were used (Oasis HLB, Lichrolut EN, Bond ElutPlexa, spherical Upti-Clean C18)

18. Multi-Syringe Flow-Injection Bead-Injection Lab-On-Valve system coupled to GC

19. Samples • Samples were obtained from urban waste landfill in Santa Margalida and Mallorca in Spain • Leachates from urban solid waste landfill (Sample No.1) • Electronic equipment disposal site (Sample No.2) • Both samples were spiked at 10 and 50 ng L-1 level

20. Chromatogram of landfill leachate sample No.1 spiked at 10 ng /L level of each PCB congener and 50 ng / L of IS (PCB-166) mV 850,000 800,000 750,000 700,000 650,000 600,000 550,000 500,000 450,000 400,000 350,000 300,000 250,000 200,000 150,000 100,000 50,000 22 24 26 28 30 32 34 36 38 40 42 tR (min)

21. Analytical performance of the online BI-LOV-GC method for determination of trace level concentrations of PCBs (PCB-166 IS)

22. Sample No.3 – Aroclor 1260 • This is a mixture of PCB-28, PCB-52, PCB-101, PCB-118, PCB-153, PCB-138, PCB-180 (still in use in old transformers and capacitors) • Aroclor 1260 was spiked with a landfill leachate to get a more environmentally realistic sample (Sample 3) • First the mixture was characterized by injecting individual PCBs • Then Aroclor 1260 spiked into the leachate sample was analyzed (Total PCB 500 ng L-1, PCB-166, 50 ng L-1)

23. Chromatogram of solid waste leachate sample No.3 spiked with 500 ng / L of Aroclor 1260 and 50 ng / L of IS (PCB-166) mV 1,000,000 950,000 900,000 850,000 800,000 750,000 700,000 650,000 600,000 550,000 500,000 450,000 400,000 350,000 300,000 250,000 200,000 150,000 100,000 50,000 22 24 26 28 30 32 34 36 38 40 42 tR (min)

24. Comparison of expected and found concentrations of PCB congeners in a landfill leachate spiked with Arochlor 1260 at the 500 ng L-1 level

25. Summary • BI-LOV-GC used for the analysis of PCBs in solid waste leachates • Two solid waste leachate samples were spiked with 10 and 50 ng L-1 PCBs • Aroclor 1260 was used as a more environmentally realistic sample (total PCB concentration 500 ng L-1) • Limit of quantification is in the range of 0.5 – 6.1 ng L-1

26. Analysis of Polychlorinated biphenyls in human serum by gas chromatography – mass selective detection operating at high ion source temperatureJournal of Chromatography B, 2009, 877, 1109 – 1116 Buu N. Tran, Li Zhang, Robert Jansing, Kenneth M.Aldous* * Wadsworth Center for Laboratiries and Research, New York State Department of Health, Albany, NY 12201

27. Analysis of PCBs in human serum by GC – MS – SIM • Human serum is a complex matrix consists of proteins, lipids and inorganic salts • Extensive clean-up procedures are required prior to analysis • SPE was used for the clean-up • Agilent 6890N GC was coupled to Agilent 5975B MSD • MS was used at 70 eV for electron ionization, and scanning from 35 to 550 amu

28. Calibration of GC – MS • Decafluorotriphenylphosphine (DFTPP) was used as the reference material to evaluate the performance of the GC – MS system (EPA) • MS spectrum of DFTPP was studied at ion source temperatures 230 0C and 300 0C • Base peak is m/z 198 • Molecular ion peak is m/z 442

29. Total Ion Chromatogram of DFTPP Abundance 28000 26000 24000 22000 20000 18000 16000 14000 12000 10000 8000 6000 4000 2000 0 198.0 230 0C 442.1 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360 380 400 420 440 50000 45000 40000 35000 30000 25000 20000 15000 10000 5000 0 198.0 442.1 300 0C 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360 380 400 420 440 m / Z

30. Total Ion Chromatogram of PCB-209 Abundance 900 800 700 600 500 400 300 200100 0 497.7 230 0C 50 100 150 200 250 300 350 400 450 500 10000 9000 8000 7000 6000 5000 4000 3000 2000 1000 0 497.7 300 0C 50 100 150 200 250 300 350 400 450 500 m / Z

31. High ion source temperature (+ / –) • Enhance the molecular mass responses • Reduce signals of fragment peaks • No increase in the background • Higher sensitivity • Shorten the lifetime of the source

32. Comparison of precision, accuracy, instrumental detection limits (IDLs) of PCB mixture at two ion source temperatures

33. Method development • Newborn calf serum (NCS) was used for the method development • PCB-58 and PCB-186 were selected as IS, • Less than 1% weight in aroclors • Present in small quantities in the environment • Do not co-elute with any of the target analytes • NCS samples were spiked with 0.5 ng/g of serum per each PCBs to find the Method Detection Limit (MDL) • Three NCS samples were spiked with 1, 10 and 50 ng/g serum were used for the method validation

34. Determination of Method Detection Limit

35. Method development • Newborn calf serum (NCS) was used for the method development • PCB-58 and PCB-186 were selected as IS, • Less than 1% weight in aroclors • Present in small quantities in the environment • Do not co-elute with any of the target analytes • NCS samples were spiked with 0.5 ng/g of PCBs to find the Method Detection Limit (MDL) • Three NCS samples were spiked with 1, 10 and 50 ng/g serum were used for the method validation

36. GC/MSD chromatogram of NCS spiked PCBs at 10 ng/g serum aquired in SIM mode Abundance 58 (IS) 186 (IS) 5500 5000 4500 4000 3500 3000 2500 2000 1500 1000 500 38 28 44 77 52 195 170 206 209 20.00 30.00 40.00 50.00 Elution time (min)

37. Method validation: Precision accuracy for matrix spike PCBs at 1, 10, 50 ng/g serum

38. GC/MSD chromatogram of human serum extract acquired in SIM mode Abundance 58 (IS) 186 (IS) 11000 10000 9000 8000 7000 6000 5000 4000 3000 2000 1000 118 153 138 180 20.00 40.00 Elution Time (min)

39. Summary • PCBs were analyzed using GC – MS – SIM method • Two ion source temperatures was tested (230 0C and 300 0C) • NCS was used for the method development • Method was tested for the human serum • Limit of detection was 0.1 ng/g of serum (100 ng L-1)

40. Critique • Detection limit was lower than the EPA approved level 500 ng L-1 • Recovery % changes from experiment to experiment • Recovery % is over 100% for some PCBs

41. Acknowledgements • Prof. Robin L. McCarley • McCarley Research Group • Audience

42. Questions? http://4.bp.blogspot.com/_rL2VYON8bcY/SgnbyBIIu3I/AAAAAAAAACM/JToH_WDtZTI/s320/cartoon.jpg