污水厂污泥中全氟烷基表面活性剂的高灵敏检测方法优化

为了保证短链和长链全氟烷基表面活性剂(PASs)均具有较高的回收率,并尽量提高方法的选择性、灵敏度和精密度,对污泥中PASs的检测方法进行了优化.在选择合适固相萃取柱的基础上,对超声波辅助溶剂萃取进行优化,以解决全氟十四烷酸(PFTA)等长链PASs回收率低的问题.同时,改造液质系统以减弱全氟辛酸(PFOA)的溶出干扰,并优化仪器检测方法以获取更佳的方法检出限(MDL)和方法定量限(MQL).研究结果表明,各种PASs的MDL和MQL分别在0.05~0.20 ng·g^-1和0.20~0.40 ng·g^-1的范围内,回收率介于81%±10%~118%±11%的范围内,相对标准偏差(RSD)介于3%~17%的范围内,这说明优化后的检测方法在检测污泥样品时具有较高的灵敏度、准确性和精密度.

Optimization of sensitive determination of perfluoroalkyl surfactants in sewage sludge

The analysis method for determination of perfluoroalkyl surfactants (PASs) in sewage sludge was optimized in order to simultaneously get the better recoveries of short- and long-chain PASs and to improve the methodological selectivity, sensitivity, and precision. Based on selection of suitable cartridges for solid phase extraction (SPE), the sonication solvent extraction was optimized to overcome the low recoveries of long-chain PASs such as perfluorotetradecanoic acid (PFTA). Meanwhile, the liquid chromatography tandem mass spectrometry system was improved to mitigate the influence of perfluorooctanoic acid (PFOA) leachate on qualitative and quantitative analysis, and then the instrumental analysis method was optimized for better method detection limits (MDL) and method quantification limits (MQL). The results indicated that the MDL and MQL of all PASs ranged from 0.05 ng·g^-1 to 0.20 ng·g^-1 and from 0.20 ng·g^-1 to 0.40 ng·g^-1, respectively, while the PASs recoveries and their relative standard deviations (RSD) were in the range of 81%±10%~118%±11% and 3%~17%, respectively. These data strongly indicated that this specific-method was sensitive, precise, and accurate enough for determination of PASs in sewage sludge.