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目的建立在线标准加入-石墨炉原子吸收法测定食盐中痕量镉的方法。方法样品加入1%硝酸,以1%磷酸二氢铵+1%抗坏血酸做基体改进剂,应用标准加入法,测量值在相同基质情况下获得。结果镉含量在0~2.5μg/L范围内呈线性关系,线性相关系数为0.998~0.9996,检出限为0.06μg/L,质量检出浓度为0.003 mg/kg,在0.025、0.050、0.10 mg/kg添加不同水平回收率为92.0%~102%,相对标准偏差小于5.0%。结论本法灵敏、精密度和准确度均达到分析方法的要求,适用于食盐中镉的测定。
OBJECTIVE To establish a method for the determination of trace cadmium in table salt by graphite furnace atomic absorption spectrometry. Methods The sample was added with 1% nitric acid and 1% ammonium dihydrogen phosphate + 1% ascorbic acid as the matrix modifier. The standard addition method was used. The measured value was obtained under the same matrix. Results The content of cadmium was linear in the range of 0 ~ 2.5μg / L with a linear correlation coefficient of 0.998 ~ 0.9996. The detection limit was 0.06μg / L, the mass detection concentration was 0.003 mg / kg, and the contents of cadmium were 0.025,0.050,0.10 mg / kg with different levels of recovery was 92.0% ~ 102%, the relative standard deviation of less than 5.0%. Conclusion The sensitivity, precision and accuracy of the method meet the requirements of analytical methods and are suitable for the determination of cadmium in salt.