1 / 36

Frank Neugebauer , Cathrin Ast, Olaf Paepke 

Frank Neugebauer , Cathrin Ast, Olaf Paepke  Eurofins GfA Lab Service GmbH, Neulaender Kamp 1, 21079 Hamburg, Germany. THE TOTAL PCB-TASK: ANALYSIS OF ALL 209 PCB CONGENERS IN FISH OILS AND BIOTA HRGC-HRMS METHOD FOR ANALYSIS. PCB: History and Importance of analysis.

clio
Download Presentation

Frank Neugebauer , Cathrin Ast, Olaf Paepke 

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Frank Neugebauer, Cathrin Ast, Olaf Paepke  Eurofins GfA Lab Service GmbH, Neulaender Kamp 1, 21079 Hamburg, Germany THE TOTAL PCB-TASK: ANALYSIS OF ALL 209 PCB CONGENERS IN FISH OILS AND BIOTA HRGC-HRMS METHOD FOR ANALYSIS

  2. PCB: History and Importance of analysis

  3. PCB Analysis: How it started • Performed since the 1960s (LRGC on packed column); resolution of only about 10 signals for technical pattern. Quantification via technical mixtures as reference

  4. PCB Analysis over the time • HRGC (since 1980s on capillary columns); detection with ECD and LRMS • first assignation of the majority of single compounds, detailed pattern analysis • Quantification methods for 6 (7) identified major compounds (“indicator PCB”) • Toxicity discussion of dl-PCB since 1990s; TEF assignation (WHO-TEF) • Improvement in quantification: standard substances and quantification methods for virtually all congeners in principle available • Further toxicity and limit value discussions since 2010s; adressing different modes of toxic action for dl-/ndl-PCB • EU Food/feed limit values for dl-PCB and ndl-PCB

  5. PCB - Importance of Analysis • Minimization of human intake: Under US/California Drinking Water and Toxic Enforcement Act of 1986 (“Proposition 65”) definition of an overall “safe harbor level” of 0,09 µg/day total PCB in 2006. • Implication of analysis of a total PCB value •  implicitly asking for more sophisticated analytical methods for all PCB congeners. • Still, present methods are often the old, inaccurate ones or rely upon approximations, e.g. quantification against technical mixtures or analysis of only few “marker compounds”. Method USEPA 1668 gives only a first approach towards a total PCB method

  6. samples • analytical system • performance

  7. Samples- analytical system -performance • Starting schedule: total 25 samples, arrived in our laboratory in 2012, • Sample type: presumably processed fish oil samples of different provenience, origin South America • Characterization : Tuna (n=6) and Anchovy (n=19). Both fish are at intermediate (Anchovy =3) to high trophic level (Tuna =4) • Reporting basis: pg/g original sample (=fat) • additional marine biota (i.e. oil) samples have meanwhile also been analysed

  8. Samples - analytical system - performance • Analyses have been performed at the Eurofins GfA Lab Service GmbH Dioxin/POP competence centre, Hamburg, Germany • Analytical method: deduced from analytical EU reference method for dl/ndl-PCB with added elements from EPA1668 • Analysis for total PCB, adding up all single congeners as far as separable to congener group totals (Mono- to Decachlorobiphenyls) • 3 g oil matrix, diluted in n-hexane • Multistep cleanup: Column chromatography (silica, alumina)

  9. Samples - analytical system - performance • HRMS (Thermo DFS) / R ≥ 10.000 • 8 function method • mass calibration via FC5311 • HRGC: SGE HT8PCB* (=altered) column, • 60m * 0.25 mm i.d. * 0.25 µm dF • Temperature program 90⁰C, 1 min – 20 ⁰/min • @180 ⁰ – 2 ⁰/min @260 ⁰ – 5 ⁰/min @300⁰C – 8 min • Isotope Dilution: 35 individual 13C12-quantification standards and 7 13C12-injection standards; • 209 native standards; 10-point initial calibration; multiple 1-point-calibration daily

  10. Samples - analytical system - performance • QA/QC: Quantification standard recovery rates (40-130%), blanks, control samples. • Method LOQ at around 2pg/g per signal = compound (Mono-TriCB 5pg/g); Total PCB at 400pg total PCB/g (= 0.4 µg/kg).

  11. Findings • Difficulties

  12. Findings - Main single congeners

  13. Findings - PCB congener group concentrations + TEQ 14

  14. Findings - Congener group distribution

  15. Findings - Distribution vs. technical mixtures

  16. Findings - Distribution comparison 18

  17. Findings - Distribution comparison 19

  18. Findings - Distribution comparison (2) 20

  19. Findings - Distribution comparison (3) 21

  20. Difficulties - increased background from PFK/FC5311

  21. Difficulties - interferences Int Hx Int Hp Int Hp Hp Hx Hp Hp Hx Int Sorry, no native #126 – employ Carbon cleanup!

  22. Difficulties - HT8PCB // co-elutions

  23. Real profile - different story

  24. Summary and conclusions

  25. Summary and conclusions • Analysis of all single PCB compounds resolved to about 180 separations • Analysis of total homologue groups is possible with reasonable method and quantification performance. • The results for the evaluated fish oil samples are well within the usual range of findings, as can be deduced from individual congener results • Even with an „altered“ HT8-PCB GC column, a reasonable number of PCB congener separations are possible; unique properties

  26. Summary and conclusions • Increased baselines due to HRMS reference compounds • as well for FC5311 as for PFK • Mainly for Mono- to TriCB • Signals from Cl or 2Cl-loss of higher mass PCB congeners are sometimes a problem • Maintenance of chromatographic separation and mass separation of R≥10.000 important but not completely helpful • Especially of concern: Te #81; Pe #126 near Hp #185; • typically at 2-8% of the molecular ion signal intensities • Partially wide mass range for instrument data registration • (up to 4 chlorination degrees in a single function)

  27. Take Home Analysis of 180 PCB signals instead of 18 dl/ndl-PCB gives you an unique opportunity for having 10 times the trouble!

  28. Thank you for your attention! The R+D laboratoryteam

  29. The HT8-PCB column: • Issues and separation

  30. The HT8-PCB* Column - Issues • Polysiloxane with m-Carborane (three-dimensional • aromatic cage structure) in backbone • Unique properties for PCB separation due to selective • interactions with PCB congeners • Upon installing a HT8-PCB column, an altered elution • profile observed • Identification of new elution profile by native mix of all 209 PCB • Following communications: • HT8-PCB “sensitive to lower (storage) temperatures” (M. Oehme, pers. comm.) • Meanwhile solved problems with manufacturing (SGE, pers. comm.)

  31. DetourSimilarities: HT8PCB* vs. Active carbon HeptaCB after preparative column chromatography on active carbon

  32. Separation HT8PCB vs. HT8PCB*Example Hexa-/Heptachlorobiphenyls

  33. The HT8-PCB* Column - Separation • All together 176 practically achievable separations (peaks) under our defined quality criteria (66% valley) • counting detectable peaktops 187 separations are achieved • Comparison: HT8PCB originally gives 192 peak tops = maximal possible separations • GC separation Quality criteria have been deduced by assigning 2 critical peak pairs (PCB 60/56; PCB 180/193) • Separation and elution order has been stable over 6 month and several hundred injections

  34. 155 150 152 145 148 136 154 151 155 140 143 134 133 142/131 146 168 137 130 163/164 138/160 158 129 166 161 132/153 163/164 167 156 159 162 128 157 169 The HT8-PCB* Column - Separation 135/144/147 149/139 165 141 37

  35. Findings - Congener group distribution

  36. Findings - Distribution: comparison 39

More Related