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目的建立以亚临界水萃取(subcritical water extraction,SCWE)及电感耦合等离子体质谱(inductively coupled plasma mass spectrometry,ICP-MS)检测茶叶中铅(Pb)、铬(Cr)、镉(Cd)、砷(As)4种重金属元素残留量的方法。方法待测茶叶样品在5 MPa、150℃的亚临界条件下经提取15 min后,用ICP-MS测定。结果各目标物在1~50 mg/kg范围内线性关系良好,相关系数均大于0.999。对茶叶基质进行1.0、5.0和10.0 mg/kg三个水平的加标回收实验,4种重金属元素的回收率为70.19%~113.25%,相对标准偏差RSD<8.2%。结论本方法的灵敏度、准确度和精密度均符合重金属元素残留测定的技术要求,适用于茶叶中重金属元素残留的检测。
Objective To establish a method for the determination of lead, chromium, cadmium, arsenic in tea by subcritical water extraction (SCWE) and inductively coupled plasma mass spectrometry (ICP-MS) (As) 4 kinds of heavy metal elements in the residue. Methods The tea samples tested were extracted with 5 MPa and 150 ℃ for 15 min under subcritical conditions and determined by ICP-MS. Results The linearity of each target in the range of 1 ~ 50 mg / kg was good, and the correlation coefficients were all greater than 0.999. The recoveries of four heavy metal elements were 70.19% ~ 113.25%. The relative standard deviations (RSDs) were less than 8.2%. Conclusion The sensitivity, accuracy and precision of the method are in line with the technical requirements of determination of heavy metal elements residues, suitable for the detection of residues of heavy metal elements in tea.