石墨炉原子吸收光谱法直接测定乳制品中铬

Determination of chromium in dairy products by graphite furnace atomic absorption spectrometry

目的建立乳制品经稀释液稀释后炉内直接消化测定铬的方法。方法不同乳制品用相应浓度的HNO3和Triton X-100溶液按比例稀释后测定;探讨样品处理后悬浮液的均匀稳定时间;通过不同温度、吸光度对比来确定升温程序;并对方法的精密度、准确度和检测限进行验证。结果样品处理后悬浮液的均匀稳定时间能够满足测定要求;不使用基体改进剂,升温程序采用灰化温度1000℃30 s、原子化温度2300℃5 s。溶液浓度在0μg/L^20μg/L范围内标准曲线线性良好,r=0.9995;样品RSD为2.5%~2.9%,方法的检出限为0.43μg/kg。结论本方法炉内消化直接进样,具有较好的灵敏度、准确度,方便快捷,适合日常样品的检测工作。

Objective To establish a method for direct determination of chromium in diluted diary products samples by graphite furnace atomic absorption spectrometry. Methods Different diary products samples were diluted with solution of HNO3 and Tri- tonX - 100 to determine chromium content. Duration of uniformity and stability of sample suspension, temperature programming based on temperature and absorbaney, as well as the accuracy, precision and detection limit of the method were also analyzed. Results The duration of uniformity and stability of sample suspension was available. Without matrix modifier, the ashing tem- perature was 1000 ℃ 30 s and the atomization temperature was 2300 ℃ 5 s for temperature programming. The standard curve was linear within the concentration range of 0μg/L - 20 μg/L （ r = 0.9995 ）. RSD of samples was 2.5% - 2.9%. The detection limit of the method was 0.43 μg/kg. Conclusion This method has the advantages of furnace interior direct injection, high sensitivity, good accuracy and convenience, it is suitable for routine samples detection.