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目的本文优化建立了微波消解-石墨炉原子吸收光谱法测定混合膳食中的铅和镉的方法,并对实际样品进行测定。方法采用双份饭法收集某矿区居民混合膳食样品,以单因素研究方法,依次对微波消解的各试剂用量、消解时间、消解压力,石墨炉升温程序中的干燥温度、灰化温度这几个影响样品前处理的主要因素进行优化,找出微波消解和石墨炉原子吸收光谱检测的最佳条件。结果在最佳条件下,铅加标回收率为83.0%~114.9%,RSD=0.63%;镉加标回收率为97.8%~109.7%,RSD=4.35%。用建立的方法检测样品31份,计算铅、镉每周膳食暴露量,与JECFA制定的每周耐受摄入量(PTWI)进行比较发现,铅含量超标的有3份,镉含量超标的有1份。结论该方法对混合膳食样品中铅、镉的分析检测准确、快速,适用于膳食暴露评估研究。
Objective To optimize the method of microwave digestion - graphite furnace atomic absorption spectrometry for the determination of lead and cadmium in mixed meals, and to determine the actual samples. Methods The double-meal method was used to collect the mixed dietary samples of residents in a mining area. Using single-factor method, the amounts of each reagent, digestion time, digestion pressure, drying temperature and ashing temperature The main factors influencing the sample pretreatment were optimized to find out the optimum conditions for microwave digestion and graphite furnace atomic absorption spectrometry. Results Under the optimum conditions, the recoveries of lead spiked were 83.0% -114.9% with RSD of 0.63%. The recoveries of cadmium were 97.8% -109.7% with RSD of 4.35%. 31 samples were tested by established method to calculate the weekly dietary exposure of lead and cadmium. Compared with the weekly tolerable intake (PTWI) established by JECFA, there were 3 cases of excessive lead content and excessive cadmium content 1 copy. Conclusion The method is accurate and rapid for the analysis of lead and cadmium in mixed dietary samples and is suitable for the assessment of dietary exposure.