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

Parameter Parametric value Unit Notes
Acrylamide 0.10 µg/l Note 1
Epichlorohydrin 0.10 µg/l Note 1
Vinyl chloride 0.50 µg/l Note 1

• 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

Parameter Trueness Precision LOD Conditions Notes
Acrylamide To be controlled by product specifications
Epichlorohydrin To be controlled by product specifications
Vinyl chloride To be controlled by product specifications

• 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
2007 2008
Audit monitoring 1200 1300
Acrylamide 53 65
Epichlorohydrin 156 196
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/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

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/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

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
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
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
• Purgetrap 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, 251254 M.C. Bruzzoniti et al., J.
  Chromatogr. A 2004, 1034, 243247)
• 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, 285287)
• 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
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
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
• Purgetrap 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, 21632174)
• 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
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
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
  purgetrap GC-MS