| With the deterioration of source water quality,drinking water odor events in our country occur more frequently. Since May in 2007 the outbreak of ordor problem cau-sed by algal blooms in Taihu Lake,Yanghe reservoir in Qinhuangdao,Chaohu Lake in Anhui province and Dianchi Lake in Yunnan province have outbreaks of similar odor events one after another.These odor incidents has affected the daily life of local resid-ents and also attracted a lot of public attention.The compounds causing odor in water may be at trace levels and complicated, so their qualitative and quantitative tests are relatively difficult.Rencently there is not standard methods of determinating odor compounds in drinking water in our country.Through researching in this study, to establish the method for determining geosmin, dimethyl trisulfide and 2-methylisoborneol in drinking water and to provide scientific basis for formulating the standard methods of determinating odor compounds in drinking water.The main results are summarized as follows:1 To choose geosmin, dimethyl trisulfide and 2-methylisoborneol as the target compounds. Geosmin and 2-methylisoborneol are the most frequent ordor compounds in our source water which can be detected in most lake sources and river soueces.Dimethyl trisulfide has been confirmed to be the typical compound to produce marsh smelland it has been included in the Taste/odor wheel.lt is reported that dimethyl trisufide is one of the main odor compounds causing odor problem in Wuxi 2007.2 To choose the method of solid phase microextraction (SPME)as the pretreatment of samples.Through the comparison and discussion of four pretreating methods including solid-phase extraction, liquid-liquid extraction, purge and trap and solid phase microextraction,the result shows that the recoveries of SPE and LLE is lower and the sensitivity of P&T is lower.Nevertheless the recoveries and sensitivity of SPME which is more suitable to enrich the odor compounds in drinking water are better.3 Through researching on the conditions for SPME and the parameters for GC/MS,to propose the optimal conditions for SPME and the optimal parameters for GC/MS,and establishing the method for determining geosmin,2-methylisoborneol and dimethyl trisulfide in drinking water with SPME-GC/MS.4 The methodology indexs of SPME-GC/MS which determine geosmin,2-met-hylisoborneol and dimethyl trisulfide in drinking water was studied and evaluated.It was found that detection limits for three compounds were between 0.7ng/L～1.6ng/L and limits of quantaion were between2.2 ng/L～5.3ng/L.RSD was between 2.3%～8.7%.Recoveries for tap water analyses ranged between 80.1%～96.9% and recoveries for river water analyses ranged between 92.5%～102.5%.The methodology indexs of this method were better, so it can be used to determine the odor compounds in drinking water.5 Determined the water samples including anabaena algae and some field water samples.In the anabaena algae water,the determination of geosmin reached 750.71ng/L, determination of 2-methylisoborneol was only 20.21ng/L and dimethyl trisulfide was not detected.In the water sample of Taihu Lake, determination of 2-methylisoborneol was 10.10ng/L.In the water sample of Dianchi,the determination of geosmin was 6.32ng/L, determination of dimethyl trisulfide reached 195ng/L and 2-methylisoborneol was not detected.6 The SPME-GC/MS method for determining geosmin,2-methylisoborneol and dimethyl trisulfide by this study is easy to operate,quick to analysis,accurate to quantify,and verified by the investigated water samples,the characteristics of the method is in line with the requirements of the analysis of actual water samples.7 The SPME-GC/MS method established by this study is practicable,and it meets the research objectives of study design. |
PDF Full Text Request