• Nuclear Engineering and Technology
• /
• v.53 no.4
• /
• pp.1210-1217
• /
• 2021

The analysis of ⁴¹Ca in concrete generated from the nuclear facilities decommissioning is critical for ensuring the safe management of radioactive waste. An analytical method for the determination of ⁴¹Ca in concrete is described. ⁴¹Ca is a neutron-activated long radionuclide, and hence, for accurate analysis, it is necessary to completely extract Ca from the concrete sample where it exists as the predominant element. The decomposition methods employed were the acid leaching, microwave digestion, and alkali fusion. A comparison of the results indicated that the alkali fusion is the most suitable way for the separation of Ca from the concrete sample. Several processes of hydroxide and carbonate precipitation were employed to separate ⁴¹Ca from interferences. The method relies on the differences in the solubility of the generated products. The behavior of Ca and the interfering elements such as Fe, Ni, Co, Eu, Ba, and Sr is examined at each separation step. The purified ⁴¹Ca was measured by a liquid scintillation counter, and the quench curve and counting efficiency were determined by using a certified reference material of known ⁴¹Ca activity. The recoveries in this study ranged from 56 to 68%, and the minimum detectable activity was 50 mBq g^-1 with 0.5 g of concrete sample.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.38 no.4
• /
• pp.517-524
• /
• 2009

We collected 177 fishes representing 53 species of fish from the eastern (Pohang), western (Gunsan), and southern (Tongyeong) coasts of Korea, and measured their heavy metal contents. The mean recoveries of the heavy metals extracted from cod muscle (certified reference material, CRM) were $88.7{\sim}100.6%$. The mean levels of the heavy metals in the samples taken from the edible portion of each fish were high in the order of Zn ($8.981{\pm}4.835{\mu}g/g$), Cu ($0.755{\pm}0.507{\mu}g/g$), and Mn ($0.433{\pm}0.699{\mu}g/g$), which are necessary metals in the human body, and then followed by Cr ($0.206{\pm}0.181{\mu}g/g$), Ni ($0.081{\pm}0.110{\mu}g/g$), Pb ($0.038{\pm}0.046{\mu}g/g$), Cd ($0.017{\pm}0.023{\mu}g/g$). The average daily intakes of the heavy metals by the fishes were as follows: Cd (0.81 ${\mu}g$), Cr (9.98 ${\mu}g$), Cu (36.63 ${\mu}g$), Mn (21.01 ${\mu}g$), Ni (3.93 ${\mu}g$), Pb (1.84 ${\mu}g$) and Zn (435.58 ${\mu}g$). The average weekly intakes of Cd, Cu, Pb and Zn by the fishes were 1.35%, 0.12%, 0.86%, and 0.73% respectively, as compared with PTWI (Provisional Tolerable Weekly Intakes) established by FAO/WHO Expert Committee for Food Safety Evaluation.

• Journal of radiological science and technology
• /
• v.45 no.6
• /
• pp.523-529
• /
• 2022

Gamma spectroscopy analysis is widely used for radioactivity analysis, and various factors are required for radioactivity calculations. Among the factors, K3 for each sample significantly influences the results. The previous methods of correcting the self-absorption effect include a computational simulation method and a method that requires making a CRM(certified reference material) identical to the sample medium. However, the above methods have limitations when used in small institutions because they require specialized program utilization skills or high manufacturing costs and large facilities. The aim of this study is to develop a method that can be easily and rapidly applied to radioactivity analysis. After filling the beaker with water, we placed the radiation source in a uniform position and used the measured value as the benchmark. Next, a correction factor was derived based on the difference in the radiation source count of the benchmark and the identically measured sample. For the radiation source, Eu-152, which emits a broad range of energy within the measurement range of gamma rays, and Cs-134 and Cs-137, which are indicator nuclides in environmental radiation analysis, were used. The sample was selected within the density range of 0.26-2.11 g/cm³, and the correction factor was derived by calculating the count difference of each sample compared to the reference value of water. This study presents a faster and more convenient method than the existing research methods for determining the self-absorption effect correction, which has become increasingly necessary.

• Analytical Science and Technology
• /
• v.30 no.5
• /
• pp.252-261
• /
• 2017

Naturally occurring radioactive materials (NORMs) increase radiation exposure to the public as these materials are concentrated through artificial manufacturing processes by human activities. This study focuses on the development of a method for the quantitative analysis of $^{232}Th$, $^{235}U$, and $^{238}U$ in building materials. The accuracy and precision of inductively coupled plasma mass spectrometry (ICP-MS) for determination of digestion processes was evaluated for certified reference materials (CRMs) digested using various mixed acid (e.g., aqua regia, hydrofluoric acid, and perchloric acid) digestions and a $LiBO_2$ fusion method. The method validation results reveal that a $LiBO_2$ fusion and $Fe(OH)_3$ co-precipitation should be applied as the optimal sample digestion process for the quantitative analysis of radionuclides in building materials. The radioactivity of $^{232}Th$, $^{235}U$, and $^{238}U$ in a total of 51 building material (e.g., board, brick, cement, paint, tile, and wall paper) samples was quantitatively analyzed using an established process. Finally, the values of $^{238}U$ and $^{232}Th$ radioactivity were comprehensively compared with those from the indirect method using ${\gamma}$-spectrometry.

• Journal of the Society of Disaster Information
• /
• v.9 no.3
• /
• pp.249-258
• /
• 2013

Recieved Mar. 06, 2013 Revised Mar. 29, 2013 Accepted Sep. 11, 2013In this study, we evaluated the method performance and the optimum sample injection method of the portable GC/MS(HAPSITE) which were designed to operate on scene of chemical accidents. Chemicals used for performance test were vinyl chloride(VC), methyl chloride(MC), benzene(Bz), toluene(Tol). CRM(Certified Reference Material) Manufactured by KRISS(Korea Research Institute of Standards and Science) was used as the standard gas. The results showed that 1) Among three sample injection methods(Cylinder, Silico canister, and Bag), bag was identified as the most appropriate sample injection method. Bag material and capacity did not significantly affect the results. The most ideal reproducibility occurred at the 2-minute point of the purge time in the loop and tenax methods. 2) Performance evaluation of HAPSITE was conducted. Evaluation items were reproducibility, linearity, method detection limit, etc. Tenax concentration method was appropriate for larger molecules and Carbopack concentration method was suitable for smaller molecules.

• Journal of the Korean Society for Marine Environment & Energy
• /
• v.14 no.3
• /
• pp.147-153
• /
• 2011

This study is to measure the differences of the trace-metals resulted from the different ecologies, such as nickel(Ni), copper(Cu), zinc(Zn), cadmium(Cd), plumbum(Pb), arsenic(As) and chrome(Cr) remaining in the parts of Korean Yeongdeok Crab (KYC) and Russian Snow Crab (RSC) based on ICP-MS. The recovery rate of each metal certified the reference materials (CRM) was in the average of 81~99%, which corresponded with the level required in Codex. The level of metals in the parts of KYC was in the order of Ni > As > Zn > Cu > Cr > Cd in the both male and female shell; the order of Zn > As > Cu > Cr > Ni > Cd in the leg flesh; the order of Zn > As > Cu > Cr > Cd > Ni in the body flesh; the order of Cu > Zn > As > Cd > Cr > Ni in the gill; the order of Cu > As > Zn > Cd > Ni > Cr in the male hepatopancreas; the order of Cu > Zn > As > Cd > Cr > Ni in the female hepatopancreas, thereby showing some differences. It was revealed that the levels of most metals (nickel, copper, zinc, arsenic and chrome) were similar between KYC and RSC except cadmium which was somewhat lower than that of KYC. However, the cadmium in RSC was discovered in high level in most of the parts, two times higher in the hepatopancreas, and four times in the gill. It was also revealed that the trace metal contents were changing according to the size of KYC; the metals with the highest level of Ni in shell, Zn in leg and body flesh, Cu in gill tended to decrease as growing, whereas the cadmium contents tended to increase overall and accumulated the most in hepatopancreas. The results showed there was a possibility that the phenomenon of bioaccumulation within hepatopancreas would increase as growing.

• Korean Journal of Food Science and Technology
• /
• v.37 no.3
• /
• pp.352-359
• /
• 2005

Uncertainty involved during determination of vitamin C content in infant formula was quantified by indophenol titration method. Uncertainty sources in measurand, such as purity, weight, final volume of standard, volume of standard solution used for titration, sample weight, final volume of sample, extraction solution used for titration, titration of extraction solution and standard solution by indophenol solution were identified and used as parameters for combined standard uncertainty based on Guide to the expression of uncertainty in measurement (GUM) and Draft EURACHEM/CITAC Guide. Uncertainty parameters of each source in measurand were identified as resolution, reproducibility and stability of chemical balance, standard material purity, repeatability, reproducibility, end point of titration, 1 mL pipet, 5 mL autopipet, and 100 mL mass flask. Each uncertainty component was evaluated by types A and B and included to calculate combined uncertainty. Analytical test result for traceability under laboratorial conditions using Certified Reference Material (CRM) test was certified as $108.4{\pm}1.7mg/100g$, which was within CRM certification range of $114.6{\pm}6.6mg/100g$. Uncertainty test result of vitamin C content of 5 g sampling was $56.7{\pm}2.44mg/100g$. Uncertainty could be reduced by identification of uncertainty sources and components related with vitamin C determination by indophenol titration method and by decreasing uncertainty sources and components.

• The Korean Journal of Nuclear Medicine Technology
• /
• v.15 no.2
• /
• pp.116-124
• /
• 2011

Purpose: To establish accurate external quality assurance (EQA) test, cross institutional and modality tests were performed using WHO certificated reference material (CRM) and same pooled patients serum. Materials and Methods: Accuracy and precision were evaluated using CRM and pooled patients' serum for AFP, CEA, PSA, CA 125, CA 19-9, T3, T4, Tg, TSH. To evaluate the accuracy and precision, recover test and coefficient variation were measured. RIA test were performed in major 5 RIA laboratory and EIA (CLIA) test were done in 5 major EIA laboratory. same sample of CRM and pooled serum were delivered to each laboratory. Results: In 2009, mean precision of total tumor marker of RIA was $14.8{\pm}4.2%$ and that of EIA(CLIA) was $19.2{\pm}6.9%$. In 2010, mean precision of 5 tumor marker and T3, T4, Tg, TSH was $13.8{\pm}6.1%$ in RIA and $15.5{\pm}7.7%$ in EIA (CLIA). There was no significant difference between RIA and EIA. In RIA, the coefficient variations (CV) of AFP, CEA, PSA, CA 125, T3, T4, TSH were within 20%. The CV of CA 19-9 was over 20% but there was no significant difference with EIA (CLIA) (p=0.345). In recovery test using CRM, AFP, PSA, T4, TSH showed 92~103% of recovery in RIA. In recovery test using commercial material, CEA, CA 125, CA 19-9 showed relatively lower recovery than CRM but there was no significant difference between RIA and EIA (CLIA). Conclusion: By evaluating the precision and accuracy of each test, EQA test could more accurately measured the quality of each test and performance of laboratory.

• Journal of the Korean Chemical Society
• /
• v.55 no.3
• /
• pp.472-477
• /
• 2011

The concentration of selenium in grain samples was determined using isotope dilution method in ORC-ICPMS. The experimental conditions were optimized to $H_2$ mode and the flow rate was $4.0\;mL\;min^{-1}$. ORC in $H_2$ mode proved to eliminate most of polyatomic interferences except $BrH^+$ when Br is present in sample matrix. Chemical removal of Br was very difficult and the mathematical correction was successfully employed. The fraction of $BrH^+$ generated from Br at the current experimental condition was 14.1%. The signal on m/z 82 was corrected and calculated for isotope dilution. The analytical reliability of the propose method was successfully evaluated by analyzing the certified standard reference material NIST SRM 1566 and 1567. The method was applied to real samples and the results are $0.034{\pm}0.001\;{\mu}g\;g^{-1}$ for white rice, $0.059{\pm}0.002_5\;{\mu}g\;g^{-1}$ for brown rice, $0.029{\pm}0.001_4\;{\mu}g\;g^{-1}$ for black rice, and $0.034{\pm}0.002\;{\mu}g \;g^{-1}$ for barley. The detection limits ($3\sigma$) for Se was $0.012\;ng\;g^{-1}$.

• Journal of the Korean Chemical Society
• /
• v.63 no.6
• /
• pp.420-426
• /
• 2019

Selenoproteins,in Korean blood serum, GPx, SelP, and SeAlb were separated and determined with the use of HPLC-ICP/MS. Deuterium was used as a collision gas and affinity column with ammonium formate was used as an eluting solvent for the accurate quantitation of selenoproteins in human blood serum. Certified reference material BCR 639 (133±12 ng g^-1) was tested for the accuracy and the result was satisfactory 130±6 ng g^-1. Blood serum for the rectal cancer and controlled groups were collected and analyzed to give 84±27 ng g^-1, and 119±28 ng g^-1, respectively. The difference was statistically obvious when t-test was performed (t_cal 4.93 > t_95% 2.04). The decrease for cancer group was more obvious for female and aged group. The distributions of three selenoproteins were similar with each other, which means rectal cancer group did not show any specificity for any selenoproteins. As cancer developed, GPx showed a slight decrease but not obvious while the total concentration was increasing particularly at the second stage of cancer.