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

Outline Introduction Analysis of acrylamide Analysis of epichlorohydrin Analysis of vinyl chloride Summary

Council Directive 98/83/EC on the quality of water intended for human consumption ANNEX I, Part B: Chemical parameters Parameter Parametric value Unit Notes Acrylamide 0.10 µg/l Note 1 Epichlorohydrin Vinyl chloride 0.50 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

To be controlled by product specifications 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 Parameter Trueness Precision LOD Conditions Notes Acrylamide To be controlled by product specifications Epichlorohydrin Vinyl chloride No analytical determination of acrylamide, epichlorohydrin, and vinyl chloride required!!!

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…

Number of drinking water samples at TZW 2007 2008 Audit monitoring ~ 1200 ~ 1300 Acrylamide 53 65 Epichlorohydrin 156 196

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

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/cm3 Water 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

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/cm3 Water 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

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

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

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

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

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

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

Calibration curve for acrylamide

Validation parameters Acrylamide Recovery in % 85 Sensitivity in counts/ng 0.004 Relative standard deviation in % 1.0 Correlation coefficient (r²) 0.999 Limit of detection in ng/L 1.3 Limit of quantification in ng/L 4.7

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

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 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)

Principle of Solid-phase micro-extraction (SPME)

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

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)

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)

Calibration curve for epichlorohydrin

Validation parameters Epichlorohydrin Recovery in % 41 Sensitivity in counts/ng 0.134 Relative standard deviation in % 5.4 Correlation coefficient (r²) 0.996 Limit of detection in ng/L 35 Limit of quantification in ng/L 100

Chromatogram of a drinking water sample

Stability of epichlorohydrin in water

Stability of epichlorohydrin in diisopropylether

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

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

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)

Calibration curve for vinyl chloride

Validation parameters Vinyl chloride Sensitivity in counts/ng 9.74 Relative standard deviation in % 2.4 Correlation coefficient (r²) 0.999 Limit of detection in ng/L 12 Limit of quantification in ng/L 42

Chromatogram of a drinking water sample

Stability of vinyl chloride in water

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