Methods for determination of acrylamide, epichlorohydrin and vinyl chloride

1. Methods for determination of acrylamide, epichlorohydrin and vinyl chloride Dr. Frank Sacher DVGW-Technologiezentrum Wasser (TZW), Karlsruhe

2. Outline • Introduction • Analysis of acrylamide • Analysis of epichlorohydrin • Analysis of vinyl chloride • Summary

3. Council Directive 98/83/EC on the quality of water intended for human consumption • ANNEX I, Part B: Chemical parameters • Note 1: The parametric value refers to the residual monomer concentration in the water as calculated according to specifications of the maximum release from the corresponding polymer in contact with the water

4. Council Directive 98/83/EC on the quality of water intended for human consumption • ANNEX III, Part 2: Parameters for which performance characteristics are specified • No analytical determination of acrylamide, epichlorohydrin, and vinyl chloride required!!!

5. Practical experiences in Germany • Some water suppliers using polyacrylamides as coagulation aid calculate the maximum concentration of acryl amide • Some water suppliers analyse their finished water for acrylamide, epichlorohydrin, and/or vinyl chloride (independent of their treatment process or materials used in their networks) • Most water suppliers do nothing…

6. Number of drinking water samples at TZW

7. Acrylamide CAS-No.: 79-06-1 Molecular mass: 71.08 g/mol • Physical-chemical data: Melting point: 84.5 °C Boiling point: 125 °C (25 mm Hg) Vapor pressure: 0.007 mm Hg (20 °C)Water solubility:2160 g/L • Source: Monomer for production of polyacrylamides (PAA) PAA are used as coagulant aid in drinking water treatment

8. Epichlorohydrin CAS-No.: 106-89-8 Molecular mass: 92.5 g/mol • Physical-chemical data: Melting point: - 48 °C Boiling point: 116.5 °C Density: 1.18 g/cm3Water solubility:16 g/L • Source: Monomer for production of various plastic materials, especially epoxy resins which might be used for coating of storage reservoirs or as pipe materials in networks for distribution of drinking water

9. Vinyl chloride CAS-No.: 75-01-4 Molecular mass: 62.5 g/mol • Physical-chemical data: Melting point: - 159 °C Boiling point: 14 °C Vapor pressure: 3456 mbar (20 °C) Density: 0.911 g/cm3Water solubility:1.1 g/L • Source: Monomer for production of PVC which might be used as pipe material Degradation product of PCE and TCE under anaerobic conditions

10. Problems during analysis of small polar molecules • Pre-concentration of the analytes is difficult • Liquid-liquid extraction requires large solvent volumes • Conventional SPE materials are not suited for polar compounds • Chromatography of the analytes is difficult • Polarity hampers gas chromatographic determination • Retention on conventional reversed-phase HPLC columns is small • Detection of the compounds is difficult • No chromophor for sensitive UV detection • No fluorophor for fluorescence detection • No significant masses or mass fragments for MS detection • Methods used for other micro-pollutants are not suitable • Special methods have to be applied

11. Analytical methods for analysis of acrylamide (1) • HPLC/DAD analysis after direct injection (M. Weideborg et al., Water Res. 2001, 35, 2645-2652) • LOD ≈ 5 µg/L • No specific method • Ion-exclusion chromatography with MS detection (S. Cavalli et al., J. Chromatogr. A 2004, 1039, 155-159) • LOD ≈ 0.2 µg/L • Specific detection method • GC/MS-MS or GC/ECD analysis after derivatisation with penta-fluorophenyl isothiocyanate (H. Perez et al., Analyst 2003, 128, 1033-1036) • LOD ≈ 0.03 µg/L • Rather specific method • Laborious and time-consuming method

12. Analytical methods for analysis of acrylamide (2) • Solid-phase extraction on carbon material combined with planar chromatography with fluorescence detection after derivatisation with dansulfinic acid (A. Alpmann et al., J. Sep. Sci. 2008, 31, 71-77) • LOD ≈ 0.03 µg/L • Rather specific method • Laborious and time-consuming method • Solid-phase extraction on carbon material combined with GC/MS (K. Kawata et al., J. Chromatogr. A 2001, 911, 75-83) • LOD ≈ 0.02 µg/L • Suitability of method for environmental waters is doubtful

13. Analytical methods for analysis of acrylamide (3) • Evaporation of the water, LC-APCI-MS/MS (S. Chu et al., Anal. Chem. 2007, 79, 5093-5096) • LOD ≈ 0.02 µg/L • Specific detection method • Expensive instrumentation needed • Direct large volume injection, LC-MS-MS (J.M. Marin et al., J. Mass. Spectrom. 2006, 41, 1041-1048) • LOD depends on interface • LOD ≈ 10 µg/L for ESI • LOD ≈ 0.2 µg/L for APCI • Specific detection method • Expensive instrumentation needed

14. TZW method for analysis of acrylamide • Solid-phase extraction on activated carbon, LC-ESI-MS/MS • Sample volume: 200 mL • No pH adjustment • Addition of internal standard: d3-acrylamide • SPE material: 0.5 g activated carbon • Elution: 10 mL methanol • Evaporation of the solvent • Reconstitution of the dry residue in 100 mL methanol • LC column: Phenomenex Luna C18 (150 mm x 3 mm, 3 µm) • Eluent: Gradient water/methanol + 0.1 % formic acid • Injection volume: 50 µL

15. Chromatogram of a 0.075 µg/L calibration solution TIC Acrylamide Mass: 44 + 55 Acrylamide-d3 Mass: 58

16. Calibration curve for acrylamide

17. Validation parameters

18. Detection of acrylamide in drinking water TIC Acrylamide Mass: 44 + 55 Acrylamide-d3 Mass: 58 • 0.44 µg/L

19. Analytical methods for analysis of epichlorohydrin (1) • Head-space extraction with GC/ECD (L. Lucentini et al., Microchemical J. 2005, 80, 89-98; J. Gaca et al., Analytica Chimica Acta 2005, 540, 55-60) • LOD ≈ 40 µg/L • No specific detection method • Purge&trap extraction with GC/ECD (L. Lucentini et al., Microchemical J. 2005, 80, 89-98; J. Gaca et al., Analytica Chimica Acta 2005, 540, 55-60) • LOD ≈ 0.01 µg/L • No specific detection method • Solid-phase micro-extraction (SPME) with GC/FID (F.J. Santos et al., J. Chromatogr. A 1996, 742, 181-189) • LOD ≈ 0.3 µg/L (depending on fiber coating) • No specific detection method

20. Principle of Solid-phase micro-extraction (SPME)

21. Analytical methods for analysis of epichlorohydrin (2) • Aqueous-phase aminolysis (derivatisation with 3,5-difluoro-benzylamine), SPE, GC/MS (S.J. Khan et al., Anal. Chem. 2006, 78, 2608-2616) • LOD ≈ 0.01 µg/L • No specific method, very susceptible to interferences • Aqueous-phase derivatisation with sulfite, ion chromatography with conductivity detection or MS detection (M.C. Bruzzoniti et al., J. Chromatogr. A 2000, 884,251–254; M.C. Bruzzoniti et al., J. Chromatogr. A 2004, 1034, 243–247) • LOD ≈ 0.1 µg/L (CD) • LOD ≈ 0.05 µg/L (MSD) • CD is no specific detection method; reliability of the derivatisation procedure is doubtful

22. Analytical methods for analysis of epichlorohydrin (3) • Solid-phase extraction on a styrene-divinyl benzene co-polymer, GC/ECD (H.-J. Neu et al., Fresenius J. Anal. Chem. 1997, 359, 285–287) • LOD ≈ 0.1 µg/L • No specific method 1 = epichlorohydrin, 2 = 2-chloropropionic acid ethyl ester (internal standard)

23. TZW method for analysis of epichlorohydrin • According to EN 14207 • Solid-phase extraction on SDB material, GC/MS • Sample volume: 100 mL • No pH adjustment • SPE material: 0.2 g SDB material (JT Baker) • Elution: 1 mL diisopropylether • Addition of internal standard: 2-chloropropionic acid ethyl ester • GC column: RTX 502.2 (30 m x 0.25 mm x 1.40 µm) • Injection volume: 2 µL splitless • MS detection in SIM mode (m/z = 49, 57, 51, 62)

24. Calibration curve for epichlorohydrin

25. Validation parameters

26. Chromatogram of a drinking water sample

27. Stability of epichlorohydrin in water

28. Stability of epichlorohydrin in diisopropylether

29. Analytical methods for analysis of vinyl chloride (1) • Head-space extraction with GC/MS (T. Hino et al., J. Chromatogr. A 1998, 810, 141-147) • LOD ≈ 0.04 µg/L • Reliable method • Purge&trap extraction with GC/MS (K.-J. Lee et al., Bull. Korean Chem. Soc. 2001, 22, 171-178; E. Martinez et al., J. Chromatogr. A, 2002, 959, 181-190) • LOD ≈ 0.01 µg/L • No specific detection method

30. Analytical methods for analysis of vinyl chloride (2) • Solid-phase micro-extraction (SPME) with GC/MS (A. Dias Guimaraes et al., Intern. J. Environ. Anal. Chem. 2008, 88, 151-164) • LOD ≈ 0.25 µg/L (depending on fiber coating) • Reliable method • Head-space SPME with GC/FID (P. Tölgyessy et al., Petroleum & Coal 2004, 46, 88-94) • LOD ≈ 0.01 µg/L • Method is susceptible to interferences • Head-space SPME with GC/MS (M.A. Jochmann et al., Anal. Bioanal. Chem. 2007, 387, 2163–2174) • LOD ≈ 0.9 µg/L • Reliable method

31. TZW method for analysis of vinyl chloride • Purge & Trap GC-MS (similar to EPA method 524.2) • Purge & trap system: PTA-3000 from IMT • Sorbent material: Tenax • Sample volume: 10 mL • No pH adjustment • Addition of internal standard: bromotrichloromethan • Sample temperature: 35 °C • Trap temperature: -65 °C • Purge time: 15 min • GC column: RTX 624 (30 m x 0.32 mm x 1.80 µm) • MS detection in SIM mode (m/z = 62, 64)

32. Calibration curve for vinyl chloride

33. Validation parameters

34. Chromatogram of a drinking water sample

35. Stability of vinyl chloride in water

36. Summary • European Drinking Water Directive does not require any analytical determination of acrylamide, epichlorohydrin and vinyl chloride but refers to a calculation method • Due to their low molecular weight and their high polarity, trace-level analysis of acrylamide, epichlorohydrin and vinyl chloride in drinking waters is a challenging task • Recommended method for acrylamide is SPE on carbon material combined with LC/MS-MS detection • Recommended method for epichlorohydrin is EN 14207 (SPE on SDB material combined with GC/MS) • Recommended method for vinyl chloride is purge&trap GC-MS