摘要
目的建立管式燃烧炉/氧弹燃烧装置-液体闪烁计数法分析海产品中^(14)C的活度浓度,实现各类海产品中^(14)C的准确测定。方法采集鱼类、甲壳类、贝类及藻类4大类海产品样本,使用管式燃烧炉或氧弹燃烧装置高温氧化分离CO_(2),并用液闪测量^(14)C的活度浓度。通过研究管式燃烧炉的升温节点和升温速率优化燃烧条件,研究氧弹燃烧装置NaOH吸收液的放置方式以优化CO_(2)收集条件,研究不同闪烁液的效果及吸收法和悬浮法两种样品制备方法的避光时间以优化测量条件,从而实现海产品中^(14)C的准确测定。结果使用管式燃烧炉进行氧化燃烧时,样品热解温度区的升温速率为1.5℃/min最佳,各类海产品的燃烧效率均能达95%以上。使用氧弹燃烧装置时,在氧弹内部和尾气端同时放置二氧化碳吸收液,比传统尾气端吸收效率高10%。吸收法制备的样品在液闪测量前需要避光静置10 h以上,而悬浮法至少需20 h。两种氧化燃烧方式与两种样品制备方法得到的结果无明显差异,探测限为9.10 Bq/(kg·干样)(取样量3 g,测量时间300 min),相比于悬浮法制样(两种氧化燃烧装置得到结果的相对标准偏差分别为9.00%和8.27%),吸收法制样(对应的相对标准偏差分别为3.60%和3.29%)的精密度更高。结论管式燃烧炉及氧弹燃烧装置和两种制样方法均适用于海产品中^(14)C的测定。
Objective To develop a method for determining^(14)C in seafood using a tube combustion furnace(or oxygen bomb combustion devices)coupled with liquid scintillation counting(LSC),in order to accurately determine^(14)C in seafood.Methods Four categories of seafood samples(i.e.,fish,crustaceans,mollusks,and algae)were collected.They were then subjected to high-temperature oxidation using a tube combustion furnace or oxygen bomb combustion devices to isolate CO_(2),followed by an analysis of the radioactivity concentration of^(14)C using LSC.The combustion conditions were optimized by investigating the heating nodes and rates in the oxidation combustion furnace,and the CO_(2)collection conditions were optimized by placing a NaOH absorption solution in the oxygen bomb combustion devices.Additionally,the optimal measurement conditions were determined by comparing the effects of varying scintillation cocktails and the dark adaptation time of two preparation methods,i.e.,the adsorption and suspension method.Results When a tubular combustion furnace was used for oxidation and combustion,the optimal heating rate of the sample pyrolysis temperature zone was determined at 1.5℃/min.In this case,the combustion efficiency of various seafood could reach over 95%.When the oxygen bomb combustion devices were employed,placing NaOH solutions both inside and at the exhaust end increased absorption efficiency by 10%compared to the traditional practice of placing a NaOH solution only at the exhaust end.Samples prepared using the absorption method should be kept in the dark for at least 10 h before measurement using LSC,while samples prepared with the suspension methods should be kept for at least 20 h.The results obtained using two preprocessing devices and two sample preparation method were consistent,with a detection limit of 9.10 Bq/kg(dry samples).Compared to the suspension method(The relative standard deviation of the results obtained by two preprocessing devices were 9.00%and 8.27%),the absorption method(the corresponding relative standard deviation were 3.61%and 3.29%)exhibited higher precision in repeated measurements.Conclusions The aforementioned pretreatment devices and sample preparation method are suitable for determining^(14)C in seafood.
作者
钱宇欣
谢雨晗
石岑
尹亮亮
吉艳琴
Qian Yuxin;Xie Yuhan;Shi Cen;Yin Liangliang;Ji Yanqin(Key Laboratory of Radiological Protection and Nuclear Emergency,China CDC,National Institute for Radiological Protection,Chinese Center for Disease Control and Prevention,Beijing 100088,China)
出处
《中华放射医学与防护杂志》
北大核心
2025年第9期892-897,共6页
Chinese Journal of Radiological Medicine and Protection
关键词
海产品
管式燃烧炉
氧弹燃烧装置
液体闪烁谱
^(14)C
Seafood
Tube combustion furnace
Oxygen bomb combustion
Liquid scintillation counting(LSC)
^(14)C
