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目的建立茶叶中镍的石墨炉原子吸收光谱测定方法。方法样品经微波消解后,分别以20 g/L磷酸二氢铵、0.2 g/L氯化钯、0.2 g/L氯化钯-20 g/L磷酸二氢铵溶液作为基体改进剂,800℃灰化,用石墨炉原子吸收分光光度法测定,氘灯扣除背景,标准曲线定量。结果以0.2 g/L氯化钯溶液为基体改进剂,能明显改善峰形和提高检测灵敏度。方法的标准曲线溶液浓度在0.0 ng/ml~50.0 ng/ml时,线性关系良好,其回归方程为y=0.009 6x+0.048 3,相关系数(r)为0.999 5,最低检出限为0.02 mg/kg,相对标准偏差为3.07%~4.07%,低、中、高3种镍浓度加标回收率分别为101.5%、98.4%、98.9%。结论本方法具有快速、简单、准确的特点,可满足茶叶中的镍检测。
Objective To establish a method for the determination of nickel in tea by graphite furnace atomic absorption spectrometry. Methods After microwave digestion, the samples were treated with 20 g / L ammonium dihydrogen phosphate, 0.2 g / L palladium chloride and 0.2 g / L palladium chloride - 20 g / L ammonium dihydrogen phosphate solution as matrix modifier respectively. Ashing, graphite furnace atomic absorption spectrophotometric determination of deuterium lamp background, standard curve quantitative. The results of 0.2 g / L palladium chloride solution as a matrix modifier, can significantly improve the peak shape and improve detection sensitivity. The standard curve of the method showed a good linearity when the concentration was between 0.0 ng / ml and 50.0 ng / ml. The regression equation was y = 0.009 6x + 0.048 3, the correlation coefficient (r) was 0.999 5 and the minimum detectable limit was 0.02 mg / kg, and the relative standard deviation was 3.07% ~ 4.07%. The recoveries of low, medium and high concentrations of nickel were 101.5%, 98.4% and 98.9%, respectively. Conclusion The method is fast, simple and accurate, which can meet the nickel detection in tea.