不同基体改进剂在石墨炉原子吸收法测定食品含量中的应用

Application of Different Matrix Modifiers in the Determination of Chromium in Food by Graphite Furnace Atomic Absorption Spectrometry

目的:寻找最优的基体改进剂,优化升温程序,用于石墨炉原子吸收光谱法测定食品中的铬。方法:通过优化灰化温度和原子化温度,建立硝酸镁、磷酸二氢铵、硝酸钯的石墨炉原子吸收仪器方法。考察不同基体改进剂对婴幼儿米粉、大豆粉、婴幼儿奶粉、海带粉4种质控样品中铬含量的影响,并与未加基体改进剂的检测结果进行对比,确定最合适的基体改进剂。结果:加入基体改进剂硝酸镁、硝酸钯后的测定结果的精密度优于未加基体改进剂,但准确度因样品基质而异。加入磷酸二氢铵后,与未加基体改进剂的检测结果对比,婴幼儿米粉、大豆粉、婴幼儿奶粉、海带粉4种质控样品结果的中值偏离率的绝对值分别减小了1.72%、7.39%、8.96%、0.78%,准确度和精密度均优于未加基体改进剂。结论:采用石墨炉原子吸收光谱法测定食品中铬含量,以磷酸二氢铵为基体改进剂时,其精密度和准确度都比未加基体改进剂时有所提升,同时能够降低原子化温度,有利于延长石墨管寿命。这种方法操作简便、精密度和准确度较高,具有实用性。

Objective:To search for the optimal matrix modifier and optimize the heating program for the determination of chromium in food by graphite furnace atomic absorption spectrometry.Method:A graphite furnace atomic absorption instrument method for magnesium nitrate,ammonium dihydrogen phosphate and palladium nitrate was established by optimizing ashing temperature and atomization temperature.The effects of different matrix improvers on chromium content in 4 quality control samples of infant rice powder,soybean powder,infant milk powder and kelp powder were studied,and the test results were compared to determine the most suitable matrix improver.Result:The precision of the determination results with the addition of matrix modifiers magnesium nitrate and palladium nitrate is better than that without matrix modifiers,but the accuracy varies depending on the sample matrix.After adding ammonium dihydrogen phosphate,comparison of test results with those without matrix modifier,the absolute value of the median deviation rate of the results of four quality control samples of infant Rice noodles,soybean flour,infant milk powder and kelp powder decreased by 1.72%,7.39%,8.96%and 0.78%respectively,and both accuracy and precision were better than those without matrix modifiers.Conclusion:Using graphite furnace atomic absorption spectroscopy to determine chromium content in food,when ammonium dihydrogen phosphate is used as a matrix modifier,its precision and accuracy are improved compared to those without a matrix modifier.At the same time,it can reduce the atomization temperature,which is beneficial for extending the lifespan of graphite tubes.This method is easy to operate,with high precision and accuracy,and has practicality.