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Figure 2. Mass spectrum Df l , l ,1-trichloroacetone Top: isolated from X A D 2 macroreticular resin column 2/6/75; bottom:reference spectrum from Registry of Mass Spectra (9)
is completed, the column is recleaned before sampling. A true method blank with water was not run because of organics observed in distilled water. Figure 1shows the initial part of a reconstructed gas chromatogram of the first sample (2/6/75) on 20% SE-30. Trichloroacetone is a t scan number 27. This corresponds to an absolute retention time of 4.20 min. The relative retention time to 2-ethyl-1-hexanol (absolute retention time = 9.00 min) is 0.47. Figure 2 (top) shows the mass spectra of l,l,l-trichloroacetone obtained from the GC/MS system. The base peak at m/e 43 contains over 70% of the total ionization. This peak is from the acetyl group. PBM identified l,l,l-trichloroacetone as the best match, with 1,l-dichloroacetone second. The STIRS results for substructure identification showed the following substructures among the top five listed best matches for the overall match factor: C-Cl3 (top two compounds), C=O (four compounds) and C12CC=O (three compounds). These substructures are consistent with l,l,l-trichloroacetone. The spectrum (Figure 2, top) was then compared to the reference spectrum of l,l,l-trichloroacetone in the Registry of Mass Spectral Data (Figure 2, bottom) (10). The spectra of the sample appeared to be grossly different, since the Registry Spectrum showed a base peak at mle 15, and isotopic chlorine peaks were clearly defined (e.g., 97-99-101). This was not true of the spectrum obtained from our GCIMS system which was scanned from mle 30.
Definitive identifications of l,l,l-trichloracetone were completed by direct comparison of GC retention times on the SE-30 and bentone columns and mass spectra from the GC/MS system and the mass spectra of pure reference compound on the same GC/MS system. The use of two independent isolation methods minimizes the likelihood that a compound is altered during sampling and analysis and adds a measure of assurance to the confirmation of a compound. l,l,l-Trichloroacetone was obtained from Aldrich Chem. Co., Madison, Wis. The Torresdale water purification plant began ammoniation as part of the treatment process on 4/1/75 for taste and odor contFol. When ammonia is added to the process, there is a total chlorine residual of 2.2 ppm which contains approximately 2.0 ppm monochloroamine and 0.2 ppm dichloroamine. The change of process from free chlorination to ammoniation did not appear to affect the presence of trichloroacetone. The change of the treatment process to ammoniation did not enable the water sample to be dechlorinated by Na2SO3 before it was passed through the XAD-2 column. This did not appear to affect the recovery of trichloroacetone. Apparently l,l,l-trichloroacetone was stabilized by adjustment to pH 4 during the XAD-2 sampling procedure and by extraction into chloroform by CLLE sampling. This study suggests that l,l,l-trichloroacetone can be forming slowly during the water treatment process and in the water distribution system.
Acknowledgment The authors thank Rohm and Haas Corp., Philadelphia, for the use of their GC/MS system, F. W. McLafferty and his staff, Cornel1 University, for complementary use of the initial PBM/STIRS System and his review of that aspect of the manuscript, and Commissioner Carmen F. Guarino, J. V. Radziul, and A. Hess of the Philadelphia Water Department for a review of the manuscript. Literature Cited (1) Rook, J . J., Water Treat. Exam., 23,234 (1974).
(2) Bellar, T. A., Lichtenberg, J. J., Kroner, R. C., J . A m . Water Works Assoc., 66,703 (1974). (3) EPA Interim Report to Congress, “Preliminary Assessment of Suspected Carcinogens in Drinking Water”, EPA, Washington, D.C., June 1975. (4) Morris, J. C., “Formation of Halogenated Organics by Chlorination of Water Supplies”, EPA, EPA-600/1-75-002, March 1975. (5) Bartlett, P. D., J.Am. Chem. Soc., 56,967 (1934). (6) Junk, G. A., Richard, J. J., Grieser, M. D., Witiak, D., Witiak, J. L., Arguello, M. D., Vick, R., Svec, H. J., Fritz, J. S., Calder, G. V., J . Chromatogr., 99,745 (1974). (7) Wu, C., Suffet, I. H., ASTM Special Technical Publication 582, p 90,1975. ( 8 ) McLafferty, F. W., Hertel, R. H., Villwock, R. D., Org. Mass Spectrom., 9,690 (1974). (9) Venkataraghaven, R., Kwok, K.-S., McLafferty, F. W., J . A m . Chem. SOC.,95,4185 (1973). (10) Stenhagen, E., Abrahamsson, S., McLafferty, F. W., “Registry of Mass Spectral Data”, Wiley-Interscience, New York, N.Y., 1974. Received for review November 25, 1976. Accepted J u n e 17, 1976. Financial support by the Philadelphia Water Department.
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Correct ion In the article, “Evaporation Rates and Reactivities of Methylene Chloride, Chloroform, l,l,l-Trichloroethane, Trichloroethylene, Tetrachloroethylene, and Other Chlorinated Compounds in Dilute Aqueous Solutions” [Enuiron.
Sci. Technol., 9,833-38 (1975)], by W. L. Dilling, N. B. Tefertiller, and G. J. Kallos, on page 835, Table I, the 20th compound should be CH2ClCHClCH2Cl instead of CH2ClCHClCHC12.
Volume 10, Number 13, December 1976
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