液相色谱-电感耦合等离子体质谱法检测茶叶中“美术绿”的含量

Determination of lead chrome green in tea by liquid chromatography-inductively coupled plasma mass spectrometry

目的 建立液相色谱-电感耦合等离子体质谱法检测茶叶中"美术绿"的含量。方法茶叶样品经电炉灼烧后用0.25mol/L NaOH和0.14mol/L Na_2CO_3的混合碱性提取液95℃搅拌提取灰分10min。经Agilent G3268型阴离子色谱柱分离,以50 mmol/L硝酸铵缓冲盐为流动相等度洗脱。在上机测定前调pH值至与流动相接近,采集^(52)Cr为目标物,以质谱测定。结果该斱法在5～500μg/L范围内线性良好,相兲系数为0.9996, 3个添加水平下的回收率在82.1%～100.9%,相对标准偏差小于10%,检出限为10mg/kg。结论 该斱法测定染色茶叶中的"美术绿",准确高效,适用性强,可满足市场监管的需要。

Objective To establish a method for determination of lead chrome green in tea by liquid chromatography-inductively coupled plasma mass spectrometry. Methods After the sample was burned in an electric furnace, the ash was stirring extracted with a mixed alkaline extract of 0.25 mol/L NaOH and 0.14 mol/L Na2CO3 at 95 ℃ for 10 min. The samples were separated with Agilent G3268 anion column by isocratic elution using50 mmol/L ammonium nitrate buffer salt. The pH value was adjusted to be close to the mobile phase befor e the measurement on the computer. The 52Cr was collected as the target object and then determined by mass spectrometry.Results The method had a good linearity in the range of 5-500 μg/L, and the correlation coefficient was 0.9996.The recoveries were 82.1%-100.9%, the relative standard deviation was less than 10%, and the detection limit was 10 mg/kg. Conclusion The method for determining lead chrome green in dyed tea leaves is accurate, efficient and applicable, and can meet the needs of market supervision.