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目的采用三种不同的前处理方法消化处理食品,以测定食品中铅镉等重金属,用以探讨三种前处理方法各自的优缺点。方法采用微波消解仪,电热板湿法消解,全自动消解仪消化处理食品样品,最后用石墨炉原子吸收光谱法测定样品中铅镉的含量。结果微波消解~([1-3])测定标准物质的准确度高,空白本底值低,前处理时间短,两种元素的回收率都比较高。电热板湿法消解适用于大量样本的处理,但准确度较低,空白本底值高,回收率偏低,试剂消耗量大。全自动消解仪自动完成消化前过程,可同时消化多个样品,准确度较高,空白本底值低,回收率较高,试剂消耗量大。结论采用微波消解进行样品前处理,具有快速、准确等优点,是比较理想的前处理方法,全自动消解仪更适合大批样品的前处理。
OBJECTIVE Three different pretreatment methods were used to digest foodstuffs to determine lead, cadmium and other heavy metals in foodstuffs, so as to explore the advantages and disadvantages of each of the three kinds of pretreatment methods. Methods The samples were digested by microwave digestion instrument, wet digestion by hot plate and automatic digestion instrument. The contents of lead and cadmium in the samples were determined by graphite furnace atomic absorption spectrometry. Results The results of microwave digestion ~ ([1-3]) showed high accuracy, low blankness, short pre-treatment time and high recoveries of both elements. Wet plate digestion for a large number of sample processing, but lower accuracy, the blank high background value, low recovery, reagent consumption. Automatic digestion device automatically completes the digestion process, which can simultaneously digest multiple samples with high accuracy, low background value, high recovery, and reagent consumption. Conclusion Microwave digestion sample pretreatment, with fast, accurate and so on, is an ideal pretreatment method, automatic digestion instrument is more suitable for a large number of samples pretreatment.