Study on rapid microwave-ashing pretreatment method for radioactivity monitoring in food / 中华放射医学与防护杂志

ABSTRACT

Objective To establish a rapid,high-efficiency and clean way to monitor and pretreat the radioactivity in foods.Methods Food samples,20 kg each of cabbage,crucian,shrimp,pork and 20 L of milk,were collected around Qinshan nuclear power plant,totaling 10 samples for each food.Each type of foods was arranged in two groups each with 10 samples.Samples were pretreated using traditional ashing method (TAM) and microwave ashing method (WAM) separately.HDEHP were used for 90Sr separation and measurement.Calculations were made for the time spent on food pretreatment.The ash-fresh ratio and the recovery rate of 90Sr by the two different method were calculated,with the quality of ash being evaluated.Results The mean time spent on pretreatment was cabbage 20 h,crucian 54 h,shrimp 46 h,pork 58 h and milk 74 h for TAM group,and cabbage 8.5 h,crucian 26 h,shrimp 23 h,pork 26 h and milk 30 h for WAM group,respectively.The time spent by WAM was half the time less than by TAM,especially for animal edible product.The ash-fresh ratios from WAM group were higher than from TAM group.The recovery rates of 90Sr from WAM group in the analytical process were all above 75％,higher than from TAM group.Ashes produced by WAM were hoary,uniform,carbon residue-free and fully ashed.Conclusions WAM pretreatment can pretreat food rapidly,efficiently,cleanly with less loss and better ashing effect.These can meet the requirement of rapid pretreatment of radioactivity in food.