Fresenius' Journal of Fresenius J Anal Chem (1992) 344:47-49

@ Springer-Verlag1992

Determination of halogenated acetic acids and 2,2-dichloropropionic acid in water samples

Markus Clemens and Heinz Friedrich Sch61er Hygiene-Institut der Universitfit Bonn, Sigmund-Freud-Strasse 35, W-5300 Bonn 1, Federal Republic of Germany

Received December 13, 1991; revised January 28, 1992

Summary. A new method is described for the determination chloroacetic acids were determined gas chromatographically of halogenated acetic acids and 2,2-dichloropropionic acid after extraction and derivatisation. In order to derivatise, in slightly polluted water. The acids were extracted in a light- dimethyl sulfate, diazomethane and methanol/ phase rotary perforator, derivatised with diazomethane and can all be used. The levels of detection are between 10 and determined by GC-ECD and GC-MS. The standard 50 gg/1, and are not suitable for studies on rain and deviations were in the range of 14.5-16.8%. Average re- groundwater. Thus there are only few publications about the coveries were 82%, 92% and 79% for monochloro-, existence of chloroacetic acids in atmospheric precipitation, dichloro- and , respectively. The extrac- though they are suspected as supporting the forest decline tion yields for the bromoacetic acids and dichloropropionic [13-15]. Therefore a simple and precise method for the acid were in the range of 64-85%. determination ofhalogenated acids was developed by liquid- liquid extraction with a light-phase rotation perforator ac- cording to Brodesser et al. [16, 17].

1 Introduction 2 Experimental The frequent application of volatile halogenated hydro- 2.1 Chemicals carbons, as cleaning, extraction and degreasing agents, has led to frequent introduction of these compounds into the The chemicals used are available from Merck (monochloro- environment. The decomposition of these compounds in the , , trichloroacetic acid and atmosphere and groundwater is unquestionably important. trichloroacetic acid methylester); Aldrich (monochloro- The process of breakdown of volatile halogenated hydro- acetic acid methylester, monobromoacetic acid, 2,2 dichloro- carbons in groundwater remains extensively unexplained. propionic acid), Riedel de Haan (di- and tribromoacetic Vogel and McCarthy described a reducing dehalogenisation acid); EGA-Chemie (dichloroacetic acid methylester). The of tetra- and to vinyl chloride, but they diethylether from Promochem was distilled once through a were only able to observe this process under certain distinct 2 m packed vigreux-type column. The etheric diazomethane conditions [1]. solution was made from Diazald available from Aldrich. Studies on the atmospheric disintegration are more ex- The generation of diazomethane is described elsewhere [18 - tensive. For quite some time chlorides have 20]. been identified as breakdown products during atmospheric photoreactions of volatile halogenated hydrocarbons. Additional photo disintegration products are formylchloride 2.2 Sample extraction and phosgene. The chloroacetic acids, which are washed out A 970 ml water sample was adjusted to pH 1.5 with concen- by rain and snow, are formed by hydrolysing the chloroacetic trated sulfuric acid and extracted in a light-phase rotary acid chlorides [2-4]. perforator for 2 h with 100 ml diethylether. The extraction Halogenated acetic acids are also formed in significant of water samples with diethylether in a light-phase rotary concentration by water disinfection with [5, 6]. In perforator must be done carefully, because ether will be addition, trichloroacetic acid and 2,2-dichloropropionic acid dissolved up to a certain extent in water. This leads to an are used as herbicides, and monobromoacetic acid has been increase of the water phase in the extraction vessel and used for a long time as a preservation agent. problems with the extraction. A careful method of operation Because trichloroacetic acid is also found in the human will assure water-free extractions so that drying with body as a metabolite of tetra- and trichloroethylene [7], the sulfate which could lead to losses [21] will not be necessary. first publications pointing to the formation of chloroacetic acids, and especially trichloroacetic acid, were limited to blood and urine samples. In almost every study [8-12], the 2.3 Methylation The high polarity of the halogenoacetic acids and the 2,2- Offprint requests to: H. F. Sch61er dichloropropionic acid prevents GC measurement without 48

Fig. 1. Chromatogram of an extraction of 5 6 2000 ng/1 monochloroacetic acid (1), 300 ng/1 monobromoacetic acid (2), 500 ng/1 '23 dichloroacetic acid (3), 400 ng/1 2,2- dichloropropionic acid (4), 400 ng/1 trichloroacetic acid (5), 300 ng/1 dibromoacetic acid (6) and 800 ng/1

...... ± ...... l ...... i ...... i ...... ± ...... ± ...... tribromoacetic acid (7); split 1:25

5 i0 15 20 25 30 min

Table 1. Average recoveries, standard deviations and determination 2.5 GC-MS detection limits of monochloroacetic acid (MCA), dichloroacetic acid (DCA) and trichloracetic acid (TCA) Gas chromatograph: Mega 5160 Carlo Erba; Retention gap: Phenyl-sil, desact., 5 m x 0.32 mm ID; Column: DB 5, 30 Average Standard Determination mx0.25 mm ID, 0.25 gm df; Injector: on column, 8 gl; recovery (%) deviation (%) limit (ng/1) Carrier: He 2 ml/min; MS: Finnigan-MAT, ITD 700, direct coupling, EI, 70 eV; Temperature: 35°C (2 min), 20 ° C/rain MCA 82 15.3 1500 to 75°C (6 min), 10°C/min to 200°C. DCA 92 14.5 120 TCA 79 16.4 50

3 Results and discussion Chromatography Table 2. Average extraction yields, standard deviation and determi- nation limits of monobromoacetic acid (MBA), dibromoacetic acid The esters were well separated by the column used though (DBA), tribromoacetic acid (TBA) and 2,2-dichloropropionic acid monochloroacetic acid methylester and monobromoacetic (DCP) acid methylester show a little tailing (see Fig. 1). The peak between 2,2-dichloropropionic acid methylester and tri- Average extrac- Standard Determination chtoroacetic acid methylester is a decomposition product of tion yield (%) deviation (%) limit (ng/1) tribromoacetic acid which could not be identified exactly. MBA 64 15.1 150 DBA 85 16.8 40 Recoveries and determination limits TBA 63 15.2 500 DCP 68 16.8 100 Recoveries of mono-, di- and trichloroacetic acid were deter- mined. The results shown in Table 1 are based on the data of six extractions (n = 6) at eight different concentration levels (3000 to 1000 ng/1 monochloroacetic acid, 1600 to 80 ng/1 dichloroacetic acid, and 1400 to 25 ng/1 trichloro- prior derivatisation. The sample extracts were transferred acetic acid). The recoveries were calculated using an external into calibrated test tubes with ground stop cocks and concen- standard of corresponding methylesters. For each acid the trated at 50°C without vacuum to about 0.9 ml. Then 50 ~tl lowest concentration determined with a standard deviation of cooled etheric diaz0methane were added and the sample below 20% was set as determination limit. was filled up to 1 ml with diethylether and kept for 1 h at room temperature. Diazomethane, although carcinogenic, derivatises nearly quantitatively and the by-products formed Extraction yields and determination limits do not influence the chromatography. In comparison to Methylesters of bromoacetic acids and 2,2-dichloropro- methylation with methanol/sulfuric acid, the diazomethane pionic acid were not available in the necessary purity so only method is also quicker. extraction yields could be determined. An ethereal solution of bromoacetic acids and 2,2-dichloropropionic acid, to which diazomethane was added, served as external stan- 2.4 Gas-chromatographic detection dard. Six extractions (n = 6) were carried out on seven con- Gas chromatograph: Mega 5300 Carlo Erba; Injector: split- centration levels (1500 to 50 ng/1 monobromoacetic acid, splitless, 2 ~tl, 270 ° C, split 1:25; Retention gap: Phenyl-sil, 800 to 20ng/1 dibromoacetic acid, 1500 to 15ng/1 desact., 5mx0.32mm ID; Column: CP-Sil 8 CB, tribromoacetic acid and 2000 to 50ng/1 2,2-dichloro- 25 m x 0.32 mm ID, 1.2 gm df; Carrier: He 2.0 ml/min; propionic acid). Make-up: Ar/CH4 95v:5v; Detector: ECD HT 25 Carlo The determination limits depend on the different ECD- Erba, 300 ° C; Temperature: 45 ° C (6 min), 5 ° C/min to 70 ° C responses of the acids. The high determination limit of (2 min), 10 ° C/rain to 120°C (3 min), 10 ° C/min to 180 ° C. tribromoacetic acid is due to the fact that partial decomposi- 49

5

...... ± ...... i ...... ± ...... ± ...... i ...... i ...... i ...... i ...... ± ...... L LL 5 i0 15 20 25 min 5 i0 15 20 min Fig. 2. Chromatogram of a rain sample containing 1350 ng/1 Fig. 4. Chromatogram of a swimming-pool water containing dichloroacetic acid (3) and 860 ng/1 trichloroacetic acid (5); split 5.5 gg/l dichloroacetic acid (3), 1.5 gg/1 2,2-dichloropropionic acid 1:25 (4), 6 p.g/1 trichloroacetic acid (5) and 2.4 gg/1 dibromoacetic acid (6); split 1:50

~ 5 .__..h ~ ki

...... i ...... I ...... I ...... ± ...... i ...... 1 ...... i ...... i .... I0 15 20 min 5 i0 15 20 25 min

Fig. 3. Chromatogramm of a groundwater containing 50 ng/1 Fig. 5. The same swimming-pool water as shown in Fig. 4; split trichloroacetic acid (5); split 1:25 1:130

tion takes place, confirmed by a yellow coloration of the 6. Reckhow D, Singer P (1990) AWWA April 173-180 tribromoacetic acid standard solution. 7. Filser J, Deml E (1989) VDI Ber 745:679-712 8. Triebig G, GoNer K, Schaller KH (1976) Fresenius Z Anal The method developed was used to determine Chem 279:115-116 halogenated acetic acids in minor polluted waters (rain, snow 9. Van der Hoeven R, Drost RH, Maes RAA, Drost F, Plomp T, and ground water) and swimming-pool water - see Plomb GJJ (1979) J Chromatogr 164:106-108 Figs. 2-5 [22]. Samples containing high yields of 10. Bartos J (1979) Analysis 7:445-446 halogenated acetic acids, such as swimming-pool waters do 11. Lindner J, Langes K (1974) Mitt Lebensm Gerichtl Chem not need to be diluted, because the split can be increased if 28:163 - 169 necessary as shown in Figs. 4 and 5. 12. Breimer DD, Ketelaars HCJ, Rossum J-M (1974) J Chromatogr GC-MS determination of halogenated acetic acids is not 88:55-63 as sensitive as the ECD. Furthermore pollution of the 13. Fuchs GR, Bfichmann K (1987) Fresenius Z Anal Chem 327:205- 212 sample, the solvent, methylation by-products and excess of 14. Renner I, Mtihlhausen D (1989) VDI Ber 745:483-496 diazomethane have much more influence on GC-MS than 15. Frank H, Vital J, Frank W (1989) Fresenius Z Anal Chem on GC-ECD. 333:713 16. Brodesser J, Sch61er HF (1987) Vom Wasser 69:61 -71 17. Nick K, Sch61er HF (1991) Fresenius J Anal Chem 343:304- References 307 1. Vogel T, Perry L, McCarty L (1985) Appl Environ Microbiol 18. Black TH (1983) Aldrichim Acta 16:3-10 49 : 1080-1083 19. Howard SF, Yip G (1971) J Assoc Off Anal Chem 54:970- 2. Kubin D, B/ichmann K, Kessel M (1989) VDI Ber 745:257- 974 265 20. Anonymus (1985) Her Majesty's Stationary Office: Chloro- 3. Zetzsch C, Becker KH (1989) VDI Ber 745:97--127 phenoxy Acidic Herbicides Trichlorobenzoic Acid, Chlorophe- 4. Renner I, Schleyer R, Miihlhausen D (1989) VDI Ber 745:705- nols, Triazines and Glyphosate in Water 15--22 727 21. Miller JW, Uden PC, Barnes RM (1982) Anal Chem 54:485- 5. Christman RF, Norwood DL, Johnson JD (1985) Sci total 488 Environ 47 : 195 -- 210 22. Clemens M, Sch61er HF (1992) Zbl Hyg (in press)