同位素标记-超高效液相色谱-串联质谱法测定茶叶中的高氯酸盐

Determination of perchlorate in tea by isotope labeling ultra high performance liquid chromatography coupled with tandem mass spectrometry

目的建立茶叶中高氯酸盐的同位素标记-超高效液相色谱-串联质谱测定法。方法茶叶样品经超纯水-甲醇(2∶3,V/V)提取后,高速离心,上清液用PRi ME HLB柱净化,再经Thermo Acclaim TRINITY P1色谱柱分离,串联质谱法检测,内标法定量。结果高氯酸盐在0.25μg/L^50.0μg/L时线性回归方程为y=0.329 86x+0.031 82,相关系数(r)为0.999 3。加标浓度为0.10 mg/kg、0.40 mg/kg、0.80 mg/kg时,绿茶、红茶、茉莉花茶的平均回收率分别为93.8%~103.5%、93.4%~98.6%、94.6%~102.7%,相对标准偏差(RSD)分别为2.4%~4.6%、3.6%~4.9%、3.7%~4.8%。检出限为2.0μg/kg。结论本方法前处理简单、灵敏度高、准确、可靠,适用于茶叶中高氯酸盐的测定。

Objective To establish a method for the determination of perchlorate in tea by isotope labeling and ultra high performance liquid chromatography coupled with tandem mass spectrometry（ UPLC-MS）. Methods The perchlorate residue in tea was extracted with ultrapure water and methanol（ volume ratio of 2∶3）,and then centrifuged. The supernatant was cleaned-up with PRi ME HLB column. The separation of perchlorate was carried out on a Thermo Acclaim TRINITY P1 column,and the detection was performed with tandem mass spectrometer with internal standard method for quantification. Results The linear regression equation was y = 0. 329 86 x ＋ 0. 031 82 when the concentration of perchlorate was within 0. 25 μg/L-50 μg/L,with the correlative coefficient（ r） as 0. 999 3. When the spiked levels were 0. 10 mg/kg,0. 40 mg/kg,0. 80 mg/kg,the average recoveries of Green tea,Black tea,Jasmine tea were within 93. 8%-103. 5%,93. 4%-98. 6% and 94. 6%-102. 7%,respectively. The relative standard deviations（ RSDs） were within 2. 4%-4. 6%,3. 6%-4. 9% and 3. 7%-4. 8%,respectively. The detection limit was 2. 0 μg/kg. Conclusion The method is simple,sensitive and accurate,and it is suitable for the determination of perchlorate in tea.