管式燃烧—液体闪烁计数法测定海产品中碳-14

Determination of carbon-14 in seafood by tube furnace oxidation combustion and liquid scintillation counting method

目的研究管式燃烧—液体闪烁计数法测定海产品中碳-14活度浓度的方法,为海产品中碳-14的监测提供技术支撑。方法通过研究黄花鱼、海白虾、梭子蟹、蛏子、海藻5种海产品干样的热解特性,设定适合海产品氧化燃烧的温控程序,并验证燃烧效果、碳元素的回收率和方法正确度、精密度。结果管式氧化燃烧装置在推荐燃烧程序下对大部分海产品的燃烧效率在98%以上,对碳元素的回收率与燃烧葡萄糖计算得到的回收率结果相近,均在95%以上。4家实验室通过测定中国糖碳标准物质中碳-14活度浓度对方法正确度进行了验证,相对误差为1.03%~3.41%,相对误差均值为2.36%;通过测定黄花鱼样品中碳-14活度浓度对方法精密度进行了验证,实验室内相对标准偏差为5.11%~9.35%,实验室间相对标准偏差为4.04%。结论采用管式燃烧-液闪测量法测定海产品中碳-14活度浓度,推荐的氧化燃烧程序对海产品更有针对性,耗时更短,方法正确度和精密度满足要求,适用于海产品中碳-14的测定。

Objective To investigate the method of tube furnace oxidation combustion and liquid scintillation counting for the determination of carbon-14 in seafood,and to provide technical support for the monitoring of carbon-14 in seafood.Methods By studying the pyrolysis characteristics of five types of dried seafood samples,including yellow croaker,white shrimp,swimming crab,clam,and seaweed,a temperature control program suitable for the oxidation combustion of seafood was established.The combustion efficiency,carbon element recovery rate,and the accuracy and precision of the method were determined.Results The combustion efficiency was more than 98%for most seafood using the recommended combustion program.The recovery rate of carbon was similar to that calculated by glucose combustion;both were more than 95%.Four laboratories validated the accuracy of the method by measuring the carbon-14 activity concentration in the Chinese sugar carbon standard material.The relative errors ranged from 1.03%to 3.41%and the average relative error was 2.36%.The precision of this method was verified by measuring the carbon-14 activity concentration in yellow croaker samples.The within-laboratory relative standard deviation ranged from 5.11%to 9.35%and the between-laboratories relative standard deviation was 4.04%.Conclusion The tube furnace oxidation combustion and liquid scintillation counting method was used to determine the activity concentration of carbon-14 in seafood.The recommended oxidation combustion program is more targeted and less time-consuming.The accuracy and precision of this method meet the requirements.This method is suitable for the determination of carbon-14 in seafood.