• Analytical Science and Technology
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• v.14 no.2
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• pp.131-139
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• 2001

There is personal difference in the concentrations of trace elements in human hair according to human life or history suck as occupation, race, sex, age, food habit, social condition and so on. It is also found that the individual's deviation of elemental concentrations is reflecting the degree of environmental pollutants exposure to human body, intakes of food and metabolism. To compare the degree of accumulation in the hair tissue, human hair samples were collected from five positions of head and analyzed by non-destructive neutron activation analysis with and without washing according to IAEA's recommended method. Analytical quality control is performed using the certified reference material. The relative error of Cu, Cr, Na, Co, Mg, As, Se, Zn and those of Mn, Ca, Fe, Sr are within ${\pm}5%$ and ${\pm}10%$, respectively and the relative standard deviation of elements are within ${\pm}10%$. The deviations between the individuals and hair sampling positions were estimated. The deviation of individual was seven times more than that of positions. Under the defined condition, the difference and the correlation of elemental concentrations were compared with two different groups, office and factory workers. The result can be used as a fundamental data for human health and environment assessment.

• Analytical Science and Technology
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• v.16 no.2
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• pp.152-158
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• 2003

This study was conducted to evaluate two sample digestion procedures and instrumental determination parameters for analysis of lead in bone. Amputated human legs were treated by acid digestion or microwave dissolution prior to spectrometric analysis. Inductively coupled plasma mass spectrometry (ICP-MS) and graphite furnace atomic absorption spectrometry (GF-AAS) were used for determining bone lead levels. Recovery efficiencies using standard reference material from acid digestion measured by ICP-MS were in good agreement with those of the certified value, but in cases of acid digestion by GF-AAS and microwave digestion by both two methods, recovery underestimated and overestimated, respectively. For the bone samples, the lead concentrations obtained by ICP-MS after acid digestionwere in good agreement with those by GF-AAS (correlation coefficient = 0.983), but GF-AAS gave systematically higher values than ICP-MS. While a good agreement between two analytical methods after microwave digestion was also obtained (correlation coefficient = 0.950), bone lead concentrations from microwave were relatively higher than those from acid digestion. In conclusion, the use of the simple nitric acid digestion procedure at an ambient temperature coupled to ICP-MS seems to be efficient for the determination of lead in bone in consideration for both the convenience and validity.

• Bulletin of the Korean Chemical Society
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• v.35 no.11
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• pp.3289-3293
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• 2014

Femtosecond laser ablation (fs LA) was used in this study to identify pollution by heavy metals and the distribution of elemental nutrients at different rice milling ratios. Polished rice (degrees of milling of 3, 5, 7, 9, and 11) was collected from major Korean supermarkets and one sample thereof was selected. An internal quality control experiment was conducted using a rice flour certified reference material from the Korea Research Institute of Standards and Science (KRISS CRM) for the evaluation of the efficacy. To assess the effectiveness of the analysis method, the reliability was validated using a food analysis performance assessment scheme (FAPAS), with chili powder serving as an external quality control. The results of the analysis of the inorganic elements Ti, Ca, Al, Fe and Mn in white and brown rice with degrees of milling of 3, 5, 7, 9 and 11 using ICP-MS, ICP-OES and AAS revealed contents of 0.40, 49.2, 2.43, 5.36 and 10.3 mg/kg in white rice and 0.59, 78.0, 7.52, 11.0 and 18.5 mg/kg in brown rice, respectively. Among the elements, there were remarkable differences in the measured contents. By comparing the contents of the elements at different degrees of milling, Ti, Co, As, Ca, Al, Cu, Fe, and Mn were determined to be distributed on the surface of the rice grains, whereas the contents of Cd and Pb increased toward the center of the rice grains, and Si was evenly distributed. After the quantitative analysis of rice samples polished to different degrees of milling, Ca and Al, which were contained in large amounts, and Si were analyzed with specificity by fs LA. The results show that Ca and Al were distributed in the rice husk (protective covering of rice) and Si was distributed in all parts of the rice.

• Progress in Medical Physics
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• v.25 no.1
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• pp.8-14
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• 2014

The amounts of radioactive wastes to be disposed in the medical institute have been increased due to development of radiation diagnosis and therapy rapidly. They are produced mostly by the very short lived radioisotopes such as $^{18}F$ used in PET/CT, $^{99m}Tc$, $^{123}I$, $^{125}I$ and $^{201}Tl$, etc. IAEA proposed a criteria for the clearance level of waste which depends on the individual ($10{\mu}Sv/y$) and collective dose (1 man-Sv/y), and concentration of each nuclide (IAEA Safety Series No 111-P-1.1, 1992 and IAEA RS-G-1.7, 2004). Radioactive wastes of $^{18}F$, $^{99m}Tc$, $^{123}I$, $^{125}I$ and $^{201}TI$ in the several types of container like Marinelli beaker, vial and plastic, were collected to measure the concentration of the waste of each nuclide in accordance with IAEA criteria. The measurement method and procedure of determining specific activity of the wastes using gamma emitters like MCA, gamma counter and beta emitters were developed. For the efficiency calibration of the detectors, CRM (certified reference material) which has the same dimension and shape was provided by Korea Research Institute of Standards and Science (KRISS). Correction factor of the radioactivity decay was calculated based on the measurement results, and the consideration of mutual relation with theoretical equation. The result of this study will be proposed as ISO standard.

• Journal of Korean Traditional Oncology
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• v.16 no.1
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• pp.41-53
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• 2011

Background and Objectives: Iodine is an essential constituent of the thyroid hormones associated with the growth and development of humans and animals as an inorganic nutrition. This element may be accumulated in human blood, tissues and body through the intake of foodstuffs, a beverage, a nutritional supplement and a medicine, among others. The aim of the research is to find out a better medicinal stuff for the thyroid cancer patient who required a low level of iodine diet. Methods: Neutron activation analysis (NAA) used for the iodine analysis is one of nuclear analytical techniques using radiation and radioisotopes and very useful as sensitive analytical technique for performing both qualitative and quantitative multi-elemental non-destructive analysis of major, minor and trace components in variety of environmental and biological materials. In this study, iodine contents in ten kinds of oriental herb medicinal products, which is frequently used to cancer patients are determined by using instrumental neutron activation analysis (INAA) at the HANARO research reactor. The samples prescribed are manufactured as powdered form for taking medicine easily. The analytical quality control is performed to assure an uncertainty of the measurement and to compensate the measured data using a biological certified reference material, NIST SRM 1572, Citrus Leaves. The measured value is $1.89{\pm}0.35mg/kg$, and the relative error is 2.88%, and relative standard deviation is 19 % due to high counting error by small counts of gamma ray spectrum. The standard deviations for other elements such as Cl, K, Mn and Na were in the range of 2 to 8%. Result: The level of iodine contents of Biki-huan, Chungryong-huan and Chungcho-huan, samples detected is less than 6 mg/kg except Hangam Plus sample (more than 210 mg/kg) and six samples were not detected. Iodine in the samples of Shoxiho-tang, Shopunghualhyl-tang, Shocungryong-tang, Banhasaxim-tang, Insampaedox-san and Myunyuk Plus were not measured, but possible level of content can be estimated from the detection limits. In addition, the concentrations of some major elements like Cl, K, Mn, Na, in the samples were determined with the detection limits. Conclusions: Most of samples showed low iodine contents of less than 6 mg/kg but it turned out that most of testing samples can be used to classify the level of iodine diet samples considering the recommended low level of iodine diet 50 ${\mu}g$/day, and a better medicinal stuff for the thyroid cancer patient can be found.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.22 no.3
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• pp.200-208
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• 2012

Objectives: This study investigated the performance of three separate units of a portable photoionization detector (PID, ppb-RAE 3000) for measuring volatile organic compounds (VOCs) in a laboratory. Methods: A laboratory evaluation of the accuracy, precision, and inter-instrumental variance of three separate units of a portable PID (ppb-RAE 3000) was performed. The evaluation was based on the preparation of a test air sample of known toluene or ethylacetate concentration in a Tedlar$^{(R)}$ bag. The test air sample was monitored and data were logged consecutively by the three PIDs. A certified gas of 50 ppm toluene was also monitored during the test to ensure the reliability of the generated test air sample. Four different concentrations ranging from 0.1 to 2 TLV were used and a series of five measurements for each concentration level was performed. The accuracy was evaluated using National Institute for Occupational Safety and Health (NIOSH) criteria. Results: The results from the oldest ppb-RAE3000 unit among the three test units generally fell outside the NIOSH recommended accuracy criteria of ${\pm}25%$, whereas the other two units produced results which were acceptable at, or greater than, 25 ppm of toluene, or 0.5 TLV. These units also met the NIOSH criteria for some ethylacetate measurements but the results were not consistent. Conclusions: Considering the inconsistent performance of these ppb-RAE 3000 units, this device may not be appropriate for use as an alternative to the standard measurement methods. However, it can serve good survey instruments to identify exposure sources or concentration profiles. For all applications, the ppb-RAE 3000 should be used with frequent calibration checks, additional validation using a reference material, and careful maintenance.

• Nuclear Engineering and Technology
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• v.55 no.4
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• pp.1460-1467
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• 2023

A robust approach was conducted to determining the absolute oral bioavailable (f_ab) fractions of ²³⁸U and ²³²Th in rats exposed to contaminated soil along with their hematotoxicity and nephrotoxicity. The soil sample is the International Atomic Energy Agency-312 (IAEA-312) certified reference material, whereas blood, bones, and kidneys of in vivo female Sprague-Dawley (SD) rats estimate ²³⁸U- and ²³²Th-f_ab fractions post-exposure. We predict the bioavailable concentration (C_ab) and f_ab values of ²³⁸U and ²³²Th after acute soil ingestion. The blood ²³⁸U (0.750%) and ²³²Th (0.028%) reach their maximum f_ab values after 48 h. The ²³⁸U (f_ab: 0.169-0.652%) accumulates mostly in the kidney, whereas the ²³²Th (f_ab: 0.004-0.021%) accumulates primarily in the bone. Additionally, ²³⁸U is more bioavailable than ²³²Th. Post 48 h acute ingestion demonstrates noticeable histopathological and hematological alterations, implying that intake of ²³⁸U in co-contaminated soil can lead to erythrocytes and proximal tubules damage, whereas, ²³²Th intake can harm erythrocytes. Our study provides new directions for future research into the health implications of acute oral exposures to ²³⁸U and ²³²Th in co-contaminated soils. The findings offer significant insight into the utilization of in vivo SD rat testing to estimate ²³⁸U and ²³²Th bioavailability and toxicity in exposure assessment.

• Analytical Science and Technology
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• v.36 no.3
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• pp.105-112
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• 2023

Lycopene, a carotenoid hydrocarbon is known to have effects on reducing cardiovascular risk factors, blood lipids, and blood pressure. Thus, a lot of supplementary foods with lycopene in several dosage forms like soft capsule filled with liquid and hard capsule filled with powder are available in a market. Recently, however, our research group found that the lycopene assay in Supplementary Food Code of South Korea is only valid for oily lycopene preparation. Thus, here, we developed a simple method to determine lycopene in solid preparations for Supplementary Food Code of South Korea using saponification and liquid chromatography with an absorbance detector. The method was validated following Ministry of Food and Drug Safety guidelines. All validation parameters observed in this study were within acceptable criteria of the guidelines (selectivity, linearity of r² ≥ 0.991, lower limit of quantification of 0.0149 mg/mL, accuracy as recovery (R) between 92.70 and 97.18 %, repeatability as relative standard deviation (RSD) values of R between 0.85 and 1.59 %, and reproducibility as the RSD value of interlaboratory R of 3.70 %). Additionally, the practical sample applicability of the validated method was confirmed by accuracy between 98.81 and 101.59 % observed from its lycopene certified reference material (CRM) analyses. Therefore, the present method could contribute to fortify the supplementary food safety management system in South Korea.

• Progress in Medical Physics
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• v.33 no.4
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• pp.129-135
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• 2022

Purpose: A full-energy-peak (FEP) efficiency correction is required through a Monte Carlo simulation for accurate radioactivity measurement, considering the geometrical characteristics of the detector and the sample. However, a relative deviation (RD) occurs between the measurement and calculation efficiencies when modeling using the data provided by the manufacturers due to the randomly generated dead layer. This study aims to optimize the structure of the detector by determining the dead layer thickness based on Monte Carlo simulation. Methods: The high-purity germanium (HPGe) detector used in this study was a coaxial p-type GC2518 model, and a certified reference material (CRM) was used to measure the FEP efficiency. Using the MC N-Particle Transport Code (MCNP) code, the FEP efficiency was calculated by increasing the thickness of the outer and inner dead layer in proportion to the thickness of the electrode. Results: As the thickness of the outer and inner dead layer increased by 0.1 mm and 0.1 ㎛, the efficiency difference decreased by 2.43% on average up to 1.0 mm and 1.0 ㎛ and increased by 1.86% thereafter. Therefore, the structure of the detector was optimized by determining 1.0 mm and 1.0 ㎛ as thickness of the dead layer. Conclusions: The effect of the dead layer on the FEP efficiency was evaluated, and an excellent agreement between the measured and calculated efficiencies was confirmed with RDs of less than 4%. It suggests that the optimized HPGe detector can be used to measure the accurate radioactivity using in dismantling and disposing medical linear accelerators.

• Analytical Science and Technology
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• v.21 no.4
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• pp.284-295
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• 2008

For plastics samples, a method using combustion ion chromatography was selected as a method for rapid low-cost analysis to test whether hazardous substances are contained or not. Using combustion ion chromatography, a verification test for F, Cl and Br compounds generated a linear calibration curve with a correlation coefficient of $r^2$ = 0.999~1.000 in the calibration range from 0.5 to 4.0 mg/kg. The detection limits were found to be 0.005~0.024 mg/kg and quantitative limits were found to be 0.014~0.073 mg/kg. The recoveries of combustion ion chromatography using certified reference material (CRM) were found to be 95.5~104.9%. Based on these results, a proficiency test was conducted together with several laboratories in and out of the country, to make comparative analysis of the results from each laboratory. As a result, the data supported the use of combustion ion chromatography as an effective analysis method to deal with regulations for halogen-free electronic products and for other hazardous substances in the electronic products.