• The Journal of the Acoustical Society of Korea
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• v.20 no.6
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• pp.66-74
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• 2001

The temperature measurement of yen high temperature core melt is of importance in LAVA (Lower-plenum Arrested Vessel Attack) experiment in which gap formation between core melt and the reactor lower head, and the effect of the gap on thermal behavior are to be measured. The delay time of ultrasonic wavelets due to high temperature is suggested. As a first stage, a molten material temperature was measured up to 2300℃. Also, the optimization design of the ultrasonic temperature sensor with persistence at the high temperature was suggested in this paper. And the utilization of the theory suggested in the reference〔1〕and the efficiency of the developed system are certified by performing experiments. This sensor welded magnetostrictive element and tungsten element will be able to measure a temperature range of 3000℃ hereafter.

• Food Science of Animal Resources
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• v.34 no.6
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• pp.749-756
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• 2014

A rapid and simple analytical method for L-carnitine was developed for infant and toddler formulas by liquid chromatography tandem mass spectrometry (LC-MS/MS). A 0.3 g of infant formula and toddler formula sample was mixed in a 50 mL conical tube with 9 mL water and 1 mL 0.1 M hydrochloric acid (HCl) to chemical extraction. Then, chloroform was used for removing a lipid fraction. After centrifuged, L-carnitine was separated and quantified using LC-MS/MS with electrospray ionization (ESI) mode. The precursor ion for L-carnitine was m/z 162, and product ions were m/z 103 (quantitative) and m/z 85 (qualitative), respectively. The results for spiked recovery test were in the range of 93.18-95.64% and the result for certified reference material (SRM 1849a) was within the range of the certificated values. This method could be implemented in many laboratories that require time and labor saving.

• Environmental Engineering Research
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• v.18 no.1
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• pp.3-8
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• 2013

Collision cell technology-inductively coupled plasma-mass spectrometry (CCT-ICP-MS) was used to measure the concentrations of approximately 19 elements associated with airborne PM2.5 samples that were collected from a roadside sampling station in Daejeon, Korea. Standard reference material (SRM 2783, air particulate on filter media) of the National Institute of Standards and Technology was used for the quality assurance of CCT-ICP-MS. The elemental concentrations were compared statistically with the certified (or recommended) values. The patterns of distribution were clearly distinguished between elements with their concentrations ranging over four orders of magnitude. If compared in terms of enrichment factors, it was found that toxic trace elements (e.g., Sb, Se, Cd, As, Zn, Pb, and Cu) of anthropogenic origin are much more enriched in PM2.5 samples of the study site. To the contrary, the results of the correlation analysis showed that PM2.5 concentrations can exhibit more enhanced correlations with the elements (e.g., Fe, K, Si, and Ti) arising from earth's crust. The findings of strong correlations between PM2.5 and the elements of crustal origin may be directly comparable with the dominant role of those species by constituting a major fraction of even PM2.5 as well as PM10 at the roadside area.

• Nuclear Engineering and Technology
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• v.49 no.3
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• pp.562-568
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• 2017

Background: The chemical characterization of metallic alloys and oxides is conventionally carried out by wet chemical analytical methods and/or instrumental methods. Instrumental neutron activation analysis (INAA) is capable of analyzing samples nondestructively. As a part of a chemical quality control exercise, Zircaloys 2 and 4, nimonic alloy, and zirconium oxide samples were analyzed by two INAA methods. The samples of alloys and oxides were also analyzed by inductively coupled plasma optical emission spectroscopy (ICP-OES) and direct current Arc OES methods, respectively, for quality assurance purposes. The samples are important in various fields including nuclear technology. Methods: Samples were neutron irradiated using nuclear reactors, and the radioactive assay was carried out using high-resolution gamma-ray spectrometry. Major to trace mass fractions were determined using both relative and internal monostandard (IM) NAA methods as well as OES methods. Results: In the case of alloys, compositional analyses as well as concentrations of some trace elements were determined, whereas in the case of zirconium oxides, six trace elements were determined. For method validation, British Chemical Standard (BCS)-certified reference material 310/1 (a nimonic alloy) was analyzed using both relative INAA and IM-NAA methods. Conclusion: The results showed that IM-NAA and relative INAA methods can be used for nondestructive chemical quality control of alloys and oxide samples.

• Journal of Ecology and Environment
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• v.47 no.2
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• pp.42-48
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• 2023

An adult male Eurasian river otter (Lutra lutra) with ataxia and lethargy was rescued. Through the necropsy of this otter with neurological symptoms, a broad range of vascular damage caused by mercury toxicity in several organs, hepatocellular necrosis, and vacuolation in the brain. In mercury examination, liver, kidney, and hair showed values of 0.878 ± 0.027, 1.807 ± 0.049, and 5.712 ± 0.102 ㎍/g, respectively. Compared with certified reference material, it was confirmed that the concentration of mercury were 6.7 times, 13.7 times, and 43.3 times higher, respectively. When the symptoms and diagnosis results were comprehensively reviewed, this otter's demise was revealed due to mercury poisoning. The mercury concentration in the liver does not exceed the lowest observed effect level of 3.4 ㎍/g. However, even at low concentrations, long-term accumulation can cause symptoms including neuropathy, and the possibility that these heavy metals have accumulated in other wild animals cannot be ruled out. It seems that continuous monitoring using sentinel animals is necessary.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.21 no.2
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• pp.78-90
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• 2016

This report is to introduce detail processes during the restoration/revision project for the Korean Standard Methods for Marine Environment. The processes are composed of 3 steps: questionaries, QA/QC confirming step by CRM(Certified Reference Materials), and advisory council by specialists. The questionaries required four main topics to be included to the restoration/revision protocol: 1. the guidelines to sampling, transportation, storage, and pre-analytical procedures for the marine specimens, 2. the unified analytical method, especially for the organic compounds, 3. the QA/QC test requirement for CRM, 4. introduction of diverse analytical instruments, 5. the customer- friendly express of the protocol. Based on these new protocol, we expect two most important effects: 1, increased insurance of international credibility and equivalence by the QA/QC procedures, 2. increased conformability and representatively from wide-spread use of the protocol. Finally we suggested several residual topics remained to the inter-government cooperation.

• Analytical Science and Technology
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• v.21 no.4
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• pp.316-325
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• 2008

An inductively coupled plasma mass spectrometry (ICP-MS) instrument equipped with flow injection-hydride generation system was used for the determination of trace arsenic in seawater sample. The accuracy in this method was verified by the analysis of certified reference materials (CRM) of seawater (CASS-4, NASS-5). The analytical results agreed with certified value within the range of uncertainty. The expanded uncertainties for CASS-4 and NASS-5 in this experiment were ranged from 6.2% to 6.8% obtained from repeated analyses of the CRMs (n=5). The detection limit of $As^+$ (m/z=74.9216) in this method was confirmed about 0.01 ug/kg. Linearity obtained from calibration curve of arsenic was excellent ($R^2=1$). The detection at $As^+$ (m/z=74.9216) and $AsO^+$ (m/z=90.9165) by using oxygen reaction gas in DRC mode was compared. Sensitivity at $AsO^+$ (m/z=90.9165) was decreased about 25-fold, but the analytical results are the same that at $As^+$ (m/z=74.9216).

• Bulletin of the Korean Chemical Society
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• v.26 no.3
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• pp.440-446
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• 2005

A method is described for the determination of dibutyltin (DBT) in sediment by isotope dilution using liquid chromatography inductively-coupled plasma/mass spectrometry (LC-ICP/MS). To achieve the highest accuracy and precision, special attentions are paid in optimization and evaluation of overall processes of the analysis including extraction of analytes, characterization of the standards used for calibration and LC-ICP/MS conditions. An approach for characterization of natural abundance DBT standard has been developed by combining inductively-coupled plasma/optical emission spectrometry (ICP/OES) and LC-ICP/MS for the total Sn assay and the analysis of Sn species present as impurities, respectively. An excellent LC condition for separation of organotin species was found, which is suitable for simultaneous DBT and tributyltin (TBT) analysis as well as impurity analysis of DBT standards. Microwave extraction condition was also optimized for high efficiency while preventing species transformation. The present method determines the amount contents of DBT in sediments with expanded uncertainty of less than 5% and its result shows high degree of equivalence with reference values of an international inter-comparison and a certified reference material (CRM) within stated uncertainties.

• Analytical Science and Technology
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• v.23 no.3
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• pp.284-294
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• 2010

In this study, river water-based reference materials (RMs), NIER-I08RW and NIER-I09, for trace metal analysis were prepared and certified for Pb, Cd, Cr and Cu with evaluation of uncertainties. The RMs were confirmed to be homogeneous enough to be used as proficiency testing materials since within-bottle homogenieties of the RMs were lower than 0.3 times of targeted standard deviation of proficiency testing. The RMs were distributed to environmental testing laboratories for the proficiency testing and the variation of Z scores of the proficiency testing results were compared for different assigned values. The relative bias, $B_{relative}$, deviations between reference values and consensus values, were lower than ${\pm}$1 except for cadmium of NIERI08RW. The results showed both values were in a good agreement and only 2.9% of Z scores changed by using a different assigned values such as consensus and reference values.

• Analytical Science and Technology
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• v.28 no.6
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• pp.446-452
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• 2015

In order to evaluate and improve the ability of Korean testing laboratories to measure Polybrominated diphenyl ethers in acrylonitrile-butadiene-styrene (ABS), a proficiency test was organised by Korea Research Institute of Standards and Science (KRISS) based on ISO/IEC 17043. The proficiency test material used was 10 g of a granular ABS fortified with a mixture of congeners of PBDE (BDE-154, 183, 206, 209). Homogeneity and stability were investigated to assess the adequacy of the test material. The certified value established by KRISS based on the national reference was used for assigned value of each PBDE. The test materials were distributed to the 16 participating laboratories. The participating laboratories were requested to analyse the samples employing the methods used in their routine analysis. Each laboratory was given it’s own code to secure the anonymity. Participants results were evaluated with z-scores according to ISO/IEC 17043. The standard deviation for proficiency assessment was set by standard deviation of the participants results except for outlier. The results, the laboratory's performance and improvement of accuracy were discussed.