Determining radioactivity concentration of carbon-14 in seafood using a tube combustion system (or oxygen bomb combustion devices) coupled with liquid scintillation counting
10.3760/cma.j.cn112271-20240807-00299
- VernacularTitle:管式燃烧炉/氧弹燃烧-液闪法测定海产品中 14C活度浓度的研究
- Author:
Yuxin QIAN
1
;
Yuhan XIE
1
;
Cen SHI
1
;
Yanqin JI
1
Author Information
1. 中国疾病预防控制中心辐射防护与核安全医学所 中国疾病预防控制中心辐射防护与核应急重点实验室，北京 100088
- Publication Type:Journal Article
- Keywords:
Seafood;
Tube combustion furnace;
Oxygen bomb combustion;
Liquid scintillation counting (LSC);
14C
- From:
Chinese Journal of Radiological Medicine and Protection
2025;45(9):892-897
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To develop a method for determining 14C in seafood using a tube combustion furnace (or oxygen bomb combustion devices) coupled with liquid scintillation counting (LSC), in order to accurately determine 14C 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 14C 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 14C in seafood.
