Analysis of Volatile Compounds in Algal Bloom Water by Gas Chromatography-Mass Spectrometry and Sniffering

Volatile constituents of algal bloom water were investigated by headspace solid phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS). The compounds were quantified by normalization method based on chromatographic peak areas. HS-SPME parameters including different SPME fibers, extraction temperature and time were optimized. In our case, carboxen/polydimethyl-siloxane (CAR/PDMS) fiber was finally used for the extraction at 45 degrees C for 25 min. Aliquot of 82 volatile compounds were identified. The predominant components were butyric acid, isopentanoic acid, acetic acid, dimethyltrisulfide, n-hexanoic acid, o-cresol, propanoic acid, 2,3-dithiobutane, pentanoic acid, beta cyclocitral, methyl thiobutyrate, 3-methylindole, isopentyl alcohol, methanethiol, 1-butanol etc. The GC-MS/GC-sniffering method was employed to perform the identification of the off-flavor compounds. 18 kinds of smelly compounds were contained in algal bloom, in which dimethyltrisulfide, 2,3-dithiobutane, and beta cyclocitral were significantly increased in the later period of algal blooms outbreak.