16种嗅味物质在环境水中的稳定性及样品保存试验研究OA

To understand the stability of 16 odorous substances in environmental water and determine optimal preservation conditions,this study investigated their stability in two different matrices(surface water and tap water),as well as the effects of common sampling containers(brown hard glass and brown polyethylene),storage temperatures(20～25 ℃ at room temperature or 0～4 ℃ refrigerated),and commonly used preservatives(ascorbic acid,hydrochloric acid solution,and sodium thiosulfate).Odorous compounds in water samples were detected by solid-phase microextraction-gas chromatography-tandem mass spectrometry.Concentrations of all compounds decreased over time.Terpenoids(2-MIB,GSM)and pyrazines(IPMP,IBMP)were more stable in environmental water than ketones(β-ionone),aldehydes(β-cyclocitral,2,4-HD,2,6-ND),and aromatic heterocycles(indole).After collection,water samples should be stored in ground-mouthed hard brown glass bottles at 0～4 ℃.Polyethylene containers pose a risk of contamination from MTBE and 2,6-dichlorphenol.Compared with room temperature storage,refrigeration slows the loss of target compounds.The stability of 2,4-HD,2,6-ND,β-ionone,and indole was relatively poor in surface water,while 2,4-HD and 2,6-ND were less stable in tap water.Other compounds remained stable for up to 24 h without preservatives.In surface water,2,4-HD,2,6-ND and β-ionone should be stored with hydrochloric acid,and indole with ascorbic acid,with same-day analysis recommended.In tap water,2,4-HD can be preserved for 24 hours with ascorbic acid.The stability of odorous compounds varies by compound and matrix.Therefore,appropriate preservation methods should be applied to ensure accurate measurements.