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Use of gas chromatography-mass spectrometry-olfactometry and a conventional flask test to identify off-flavor compounds generated from phenylalanine during chlorination of drinking water
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| Title: | Use of gas chromatography-mass spectrometry-olfactometry and a conventional flask test to identify off-flavor compounds generated from phenylalanine during chlorination of drinking water |
| Authors: | Matsushita, Taku Browse this author →KAKEN DB | | Sakuma, Miki Browse this author | | Tazawa, Shiori Browse this author | | Hatase, Taiki Browse this author | | Shirasaki, Nobutaka Browse this author | | Matsui, Yoshihiko Browse this author →KAKEN DB |
| Keywords: | Chlorination | | Chlorinous odor | | Disinfection by-product | | Powdered activated carbon | | Sensory evaluation |
| Issue Date: | 15-Nov-2017 |
| Publisher: | Elsevier |
| Journal Title: | Water research |
| Volume: | 125 |
| Start Page: | 332 |
| End Page: | 340 |
| Publisher DOI: | 10.1016/j.watres.2017.08.063 |
| Abstract: | Off-flavor in drinking water can be caused by transformation products (TPs) generated from organic compounds, such as amino acids, present during chlorination. However, the contributions of many of these TPs to overall off-flavor have not been quantified, mainly because the lack of appropriate chemical standards prevents sensory evaluation by means of a conventional flask test. In the present study, we used gas chromatography mass spectrometry olfactometry (GC-MS-O) to identify compounds responsible for the off-flavor generated by chlorination of an aqueous solution of the amino acid phenylalanine, and we propose a sensory evaluation procedure for quantification of the contributions of the identified TPs to the overall off-flavor, regardless of the availability of chemical standards of the TPs. GC-MS-O revealed that two TPs, N-chlorophenylacetaldimine and 2-chloro-2-phenylacetaldehyde, for which chemical standards are not commercially available, were the main components responsible for the off-flavor of the chlorinated solution. By using a sensory evaluation procedure involving a combination of GC-MS-0 and a conventional flask test, we quantified the contributions of TPs to the overall off-flavor of the chlorinated solution. Approximately 60% of the off-flavor was attributable to free chlorine (13%), 2-chloro-2-phenylacetaldehyde (13%), trichloramine (12%) phenylacetaldehyde (11%) phenylacetonitrile (8%), and N-chlorophenylacetaldimine (2%). Treatment with powdered activated carbon (PAC) removed the off-flavor. Experiments with chlorination of N-15-labeled phenylalanine suggested that PAC reductively decomposed trichloramine into N-2 gas and adsorbed all of the other identified TPs. Superfine PAC (median diameter, 0.7 mu m) removed the off-flavor more rapidly than normal-size PAC (median diameter, 8.0 mu m). |
| Rights: | © 2017. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/ | | http://creativecommons.org/licenses/by-nc-nd/4.0/ |
| Type: | article (author version) |
| URI: | http://hdl.handle.net/2115/76129 |
| Appears in Collections: | 工学院・工学研究院 (Graduate School of Engineering / Faculty of Engineering) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)
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Submitter: 松下 拓
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