液相色谱质谱法测定沉积物中的全氟辛基磺酸和全氟辛酸

Simultaneous determination of PFOS and PFOA in sediments samples using liquid chromatography-mass spectrometry

建立了沉积物中全氟辛基磺酸(PFOS)、全氟辛酸(PFOA)的固相萃取净化及超高效液相色谱-串联质谱(UHPLC-MS/MS)测定方法。沉积物样品中的待测组分于70℃,15 m L甲醇超声萃取2次,用C18固相萃取小柱进行富集、净化,经再浓缩、定容至1.0 m L后,用Eclipse Plus-C18色谱柱、甲醇/水(含5.0 m M甲酸铵)为流动相,梯度洗脱方式进行分离;电喷雾负离子模式(ESI-)电离、多重反应监测模式(MRM)以及内标法对目标物进行定性/定量测定。优化实验条件下,方法的相对标准偏差(RSD,1.0 ng/g,n=7)分别为8.3%(PFOS)、9.1%(PFOA),沉积物样品添加0.5、2.0、5.0 ng/g浓度水平的待测目标物时,加标回收率在(82.5±9.2)%(PFOS)^(103.2±9.2)%(PFOA)之间(平行测定3次);方法在0.5~20.0 ng/g范围内,质谱信号响应与待测组分浓度呈良好线性关系,线性相关系数>0.999 0;方法的定量限(LOQ,S/N=10)为0.08 ng/g。方法具有样品前处理简单、分析速度快、选择性好的特点,适用于海洋沉积物中PFOS与PFOA的测定。

A method for simultaneous determination of PFOS and PFOA in environmental sediments samples was developed by ultra pressure liquid chromatography coupled with tandem mass spectrometry.Sediments sample was extracted by ultrasonic with 15 m L methanol twice,then enriched and purified through a C18 SPE,and finally concentrated into 1.0 m L with an automated de-solvent device.Target analytes were separated on a Eclipse Plus-C18 column using methanol-water（containing 5.0 mmol / L NH4COOH） as mobile phase.The negative electrospray ionization（ESI-） and multiple reaction monitoring mode（MRM） were utilized.The recoveries（n= 3） and relative standard deviations（RSD,n = 7） were（82.5 ± 9.2）% and 8.3% for PFOS at 0.5,2.0 and5.0 ng / g spiking levels and（103.2 ± 9.2）% and 9.1% for PFOA at 0.5,2.0 and 5.0 ng / g spiking levels,respectively.An internal standard calibration method was chosen to the quantitative analysis.The calibration curves of PFCs were linear in the range of 0.5 ~ 20 ng / g with correlation coefficients more than 0.999 0.The detection limits were 0.08 ng / g for PFOS and PFOA.The results showed that this method possessed efficiency and good selectivity,and could be used for the detection of PFOS and PFOA in marine sediments.