Study On The Determination Of The Typical Odorous Compounds In Tap Water

At present,consumers generally reflect that the tap water has odor problems,but also some complaints about the tap water odor.Tap water odor is a complex mixture,which not only contains residual chlorine or by-products of chlorine disinfection,but also contains some odorous organic compounds that have not been completely eliminateD In this paper,headspace solid phase microextraction was used as the pretreatment,combined with gas chromatography-mass spectrometry(GC-MS)and sensory gas chromatography(Sensory-GC),to study the typical odor substances and their odor characteristics in water.A method for the qualitatively and quantitatively determination of eight odorous compounds in tap water by headspace-solid phase microextraction-Gas Chromatography-Mass Spectrometry(HS-SPME/GC-MS)was developeD Several factors parameters were studied to maximize the performance of the extraction technique.Under optimized extraction conditions,the method showed a appropriate linear correlation coefficients were all greater than 0.99 for eight compounds.The method detection limits(MDL)were in range of 0.67~5.86ng/L.The relation standard deviation(RSD)were in between 1.29%~14.96%.It was investigated that the removal of residual chlorine in tap water by one time could effectively improve recoveries of eight odorous compounds,which ranging from 77.0%~128.9% in tap water.The study results proved that combining GC/MS with HS-SPME was an utility and efficient approach for the analysis of odorous compounds in tap water.The hazard quotient were below the safety level,suggesting that these eight compounds in the tap water would have not significant health effects on all age groups.GC-MS was used as qualitative technology for volatile substances in tap water.Sensory-GC was performed to determine the odor intensity and odor characteristics of each odor substances,and the odor contribution level of each odor substances to the overall odour of the tap water.The contribution level of volatile odors to the overall odor in the tap water can also be determined by detection frequency method and aromatic extraction dilution analysis(AEDA).The results showed that acetophenone,nonaldehyde and decanal had great contribution to the odour of the tap water,which was sweet orange,almond and rose scent.The tap water samples at different terminals of different water supply units were determine by GC-MS to compare the differences of volatile substances in tap water and the sources of substances.It is found that the spices,food additives,plasticizers and compounds produced by microorganisms themselves are the main substances that have an impact on the odors in the tap water.