超高效液相色谱-串联质谱法测定土壤中18种全氟和多氟烷基化合物

Determination of 18 Perfluorinated and Polyfluoroalkyl Compounds in Soil by Ultra Performance Liquid Chromatography-Tandem Mass Spectrometry

该文建立了适用于土壤中18种全氟和多氟烷基化合物(PFASs)的固相萃取/超高效液相色谱-串联质谱检测方法,包括14种全氟羧酸、3种全氟磺酸以及1种全氟醚羧酸。通过比较土壤粒径、超声温度、超声时间、固相萃取柱种类以及洗脱液浓度对PFASs提取效率的影响,确定最优前处理条件为:土壤样品过60目筛,在40℃下用甲醇超声提取10 min,分离上清液并用氮气浓缩至1~2 mL,加超纯水稀释后过WAX Oasis(150 mg/6 mL)固相萃取柱纯化,用2 mL甲醇和4 mL 0.1%氨水-甲醇对目标物进行洗脱。洗脱液氮吹定容后,采用ACQUITY UPLC BEH C_(18)柱以5 mmol/L乙酸铵溶液和甲醇为流动相进行梯度分离,电喷雾电离负离子模式(ESI-)定量分析18种PFASs。结果表明,18种PFASs在0.05~200μg/L质量浓度范围内线性良好,相关系数(r^(2))均大于0.996,方法检出限为0.003~0.100μg/L,定量下限为0.010~0.300μg/L,样品的加标回收率为76.3%~132%,相对标准偏差(RSD)为0.40%~11%。该方法前处理简单,灵敏度高,可以快速、准确地定量分析包括全氟(2-甲基-3-氧杂己酸)(GenX)在内的18种PFASs含量。

An ultra performance liquid chromatography-tandem mass spectrometry with solid phase extraction was established for the determination of 18 perfluorinated and polyfluoroalkyl compounds(PFASs)in soil,including 14 types of perfluorocarboxylic acids,3 types of perfluorosulfonic acids and 1 perfluoroether carboxylic acid.The extraction procedure for the target pollutants was optimized by comparing extraction conditions,contained soil particle size,ultrasonic temperature,ultrasonic time,types of solid phase extraction column and eluent concentration.The optimal pretreatment conditions were as follows:the soil was sieved through 60 meshes,then ultrasonically extracted at 40℃with methanol for 10 min.Then the supernatant was separated,and condensed to 1-2 mL un⁃der N2.The target was solved in ultrapure water and purified with a WAX Oasis column(150 mg/6 mL).2 mL methanol and 4 mL methanol containing 0.1%ammonia were applied to the PFASs elu⁃tion.Eluent was condensed to dryness under N2.Finally,the soil sample was concentrated into 1 mL.The target analytes were separated on an ACQUITY UPLC BEH C_(18) column using 5 mmol/L am⁃monium acetate solution and methanol as mobile phases.The negative electrospray ionization(ESI-)was utilized to analyze 18 PFASs.Results showed that there existed good linearity for 18 PFASs in the concentration range of 0.05-200μg/L with correlation coefficients(r^(2))greater than 0.996.The detection limits and the quantitation limits of the method were in the ranges of 0.003-0.100μg/L and 0.010-0.300μg/L,respectively.The recoveries ranged from 76.3%to 132%,with relative standard deviations(RSDs)of 0.40%-11%.With simple pretreatment and high sensi⁃tivity,the method could be applied to the rapid and precise quantification of 18 PFASs including GenX in soils.