A novel type of solid phase extraction element named“Magic Chemisorber” is developed for sorptive enrichment of dilute analytes from aqueous samples with high extraction efficiencies due to its capacious layer of so...A novel type of solid phase extraction element named“Magic Chemisorber” is developed for sorptive enrichment of dilute analytes from aqueous samples with high extraction efficiencies due to its capacious layer of sorbent polydimethylsiloxane.This extraction element combined with thermal desorption gas chromatography/mass spectrometry using a pyrolysis GC/MS system was applied to extract the pesticides from water samples over a concentration range of 10 -3 to 10 3 μg·l -1 .The method showed good li nearity for the tested concentration range with regression coefficients of 0 995 for over 5 decades.Limits of detection at a sub ng·l -1 (ppt)level were achieved and the reproducibility of the measurements was found to be fairly good,with relative standard deviation below 8%.展开更多
Forty-eight vinegar samples including white vinegar, rice vinegar and mature vinegar were collected from several markets in Beijing. Butyltin compounds were determined by headspace solid-phase microextraction coupled ...Forty-eight vinegar samples including white vinegar, rice vinegar and mature vinegar were collected from several markets in Beijing. Butyltin compounds were determined by headspace solid-phase microextraction coupled with gas chromatography and flame photometric detector after in situ ethylation with sodium tetraethylborate. Butyltin species were detected in sixteen vinegar samples and ranged from 0.012 to 14.10 lag Sn L 1. The detection rate of white vinegar is higher than that of rice vinegar and mature vinegar. Vinegar samples with relatively high butyltin concentration (〉1.5 μg Sn L-1) were those stored in plastic bags, indicating that the plastic bag was one of the possible sources of butyltin contamination. This was further confirmed by the leaching experiments of three selected plastic bags, and monobutyltin was detected in the leaching solvents. According to the estimation, the average daily intake of total butyltin compounds through vinegar consumption is about 0.04 ng Sn/kg b.w., much lower than the Tolerable Daily Intake (TDI) of 100 ng Sn/kg b.w. set by the European Food Safety Authority (EFSA).展开更多
文摘A novel type of solid phase extraction element named“Magic Chemisorber” is developed for sorptive enrichment of dilute analytes from aqueous samples with high extraction efficiencies due to its capacious layer of sorbent polydimethylsiloxane.This extraction element combined with thermal desorption gas chromatography/mass spectrometry using a pyrolysis GC/MS system was applied to extract the pesticides from water samples over a concentration range of 10 -3 to 10 3 μg·l -1 .The method showed good li nearity for the tested concentration range with regression coefficients of 0 995 for over 5 decades.Limits of detection at a sub ng·l -1 (ppt)level were achieved and the reproducibility of the measurements was found to be fairly good,with relative standard deviation below 8%.
基金support under the National Basic Research Program of China (2009CB421605)National Key Water Program(2009ZX07207-002-03)National Natural Science Foundation of China (20977096)
文摘Forty-eight vinegar samples including white vinegar, rice vinegar and mature vinegar were collected from several markets in Beijing. Butyltin compounds were determined by headspace solid-phase microextraction coupled with gas chromatography and flame photometric detector after in situ ethylation with sodium tetraethylborate. Butyltin species were detected in sixteen vinegar samples and ranged from 0.012 to 14.10 lag Sn L 1. The detection rate of white vinegar is higher than that of rice vinegar and mature vinegar. Vinegar samples with relatively high butyltin concentration (〉1.5 μg Sn L-1) were those stored in plastic bags, indicating that the plastic bag was one of the possible sources of butyltin contamination. This was further confirmed by the leaching experiments of three selected plastic bags, and monobutyltin was detected in the leaching solvents. According to the estimation, the average daily intake of total butyltin compounds through vinegar consumption is about 0.04 ng Sn/kg b.w., much lower than the Tolerable Daily Intake (TDI) of 100 ng Sn/kg b.w. set by the European Food Safety Authority (EFSA).
