分散微固相萃取/超高效液相色谱-高分辨质谱法测定茶叶中高氯酸盐

Determination of Perchlorate in Tea by Ultra-high Performance Liquid Chromatography-High Resolution Mass Spectrometry Coupled with Dispersive Micro Solid-phase Extraction

基于分散微固相萃取(DMSPE)技术,采用超高效液相色谱-高分辨质谱(UHPLC-HRMS)建立了茶叶中高氯酸盐的检测方法。样品采用乙腈提取,以PSA和PCX为吸附填料进行DMSPE净化,采用Poroshell 120 PFP色谱柱(50 mm×2.1 mm,1.9μm)为分析柱,甲醇-1.0%乙酸水溶液作为流动相进行梯度洗脱,内标法定量。采用负离子采集模式,靶向单一离子监测(TSIM)/数据依赖质谱(ddMS2)扫描模式进行定性筛查和定量分析。高氯酸盐在0.05~50μg/L范围内线性关系良好(r2=0.9997),方法检出限(LOD)为0.4μg/kg,定量下限(LOQ)为1.2μg/kg;在1.2、12、120μg/kg 3种加标水平下,高氯酸盐在茶叶中的平均回收率为87.4%~105%,日内相对标准偏差(RSD_(r))为0.30%~6.1%,日间相对标准偏差(RSD_(R))为4.2%~9.2%。该方法操作简单、成本低、样品净化效果好,灵敏度可满足欧盟的残留限量要求,适用于茶叶中高氯酸盐的检测,为我国茶叶中高氯酸盐的监测和风险评估提供了可靠的技术手段。

An ultra-high performance liquid chromatography-high resolution mass spectrometry(UHPLC-HRMS)was established for the detection of perchlorate in tea based on dispersive micro solid-phase extraction(DMSPE).The samples were extracted with acetonitrile,and cleaned up by DMSPE with PSA and PCX as the adsorbents.The chromatographic analysis was performed on a Poroshell 120 PFP column(50 mm×2.1 mm,1.9μm)with methanol-1.0%acetic acid aqueous solution as the mobile phase by gradient elution,and the internal standard method was used for quantitation.The qualitative screening and quantitative analysis were carried out in negative ion acquisition mode under targeted single ion monitoring(TSIM)/data dependent mass spectrometry(ddMS2)scanning mode.There was a good linear relationship for perchlorate in the concentration range of 0.05-50μg/L with its correlation coefficient(r2)of 0.9997,while the limit of detection(LOD)and the limit of quantitation(LOQ)were 0.4μg/kg and 1.2μg/kg,respectively.At three spiked levels of 1.2,12 and 120μg/kg,the average recoveries for perchlorate in tea ranged from 87.4%to 105%,with the intra-day relative standard deviations(RSD_(r))and the inter-day RSD(RSD_(R))of 0.30%-6.1%and 4.2%-9.2%,respectively.With the characteristics of easy operation,low cost,superior cleanup effect and high sensitivity which could meet the requirements for EU?s residue limit,this method is suitable for the detection of perchlorate in tea,and provides a reliable technical means for monitoring and risk assessment of perchlorate in tea in China.