• Mass Spectrometry Letters
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• v.9 no.4
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• pp.105-109
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• 2018

A certified reference material (CRM) for the analysis of inorganic nutrients in nutritional supplements has been developed. Accurate mass fractions of chromium (Cr), iron (Fe), copper (Cu), and zinc (Zn) were determined by isotope dilution inductively coupled plasma mass spectrometry (ID ICP/MS). The measurement results were used to assign certified values for the CRM, which were metrologically traceable to the definitions of the measurement units in the International System of Units (SI). Production of a candidate reference material (RM) and the certification processes are summarized. Each nutrient in the CRM showed good homogeneity, which was estimated using relative standard deviations of the measurement results of twelve bottles in a batch. This CRM is expected to be an important reference to improve reliability and comparability of nutrient analyses in nutritional supplements and related samples in analytical laboratories.

• Korean Journal of Environmental Agriculture
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• v.35 no.3
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• pp.223-233
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• 2016

BACKGROUND: This study was to develop a analytical reference material including twenty pesticides in tomato. To use it for proficiency test, the suitability of homogeneity, storage stability, assigned values and uncertainty for analytical reference material were important.METHODS AND RESULTS: In order to develop a analytical reference material of tomato for multi-residue analysis of pesticides, twenty-pesticides were treated in tomato and the samples were frozen and homogenized. The homogeneity, stability, assigned value and uncertainty were calculated according to the requirements of the KS A ISO Guide 35, KS Q ISO 13528 and EURL-PT protocol. The values of the within-bottle standard variation(s_wb) and the between-bottle standard variation(s_bb) were 0.9~6.5% of assigned value and the uncertainty(u*_bb) due to inhomogeneity was also calculated as 0.6~1.9% for all pesticides. This indicated that it was satisfactory to be used as a analytical reference material. The storage stabilities of twenty-pesticides at room temperature and freezing conditions were assessed according to the requirement of the KS Q ISO Guide 35. All pesticides were stable at room temperature (20~30℃) for 8 days and freezing (-20℃) for 23 days.CONCLUSION: The feasibility of analytical reference material for pesticide multi-residue analysis in a tomato matrix was investigated. Homogeneity of within/between-bottle, uncertainty and stabilities at room temperature and freezing condition were satisfactory for a use of proficiency test and quality control. From these results, a analytical reference material would be applicable to monitor the proficiency test of pesticide analysis organizations to improve the reliability and consistency.

• Analytical Science and Technology
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• v.23 no.1
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• pp.83-88
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• 2010

For the evaluation of our laboratory's 11-nor-${\Delta}^9$-tetrahydrocannabinol-9-carboxylic acid (THCCOOH) urinalysis test, THCCOOH urinalysis test was carried out with Certified Reference Material (CRM). The used CRM was THCCOOH in freeze-dried urine produced by NIST as Standard Reference Material 1507b. Comparing the estimated value of our laboratory with CRM, the results was coincided in the confidence level of approximately 95%.

• Analytical Science and Technology
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• v.18 no.6
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• pp.520-528
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• 2005

Two biological Certified Reference Materials (CRMs), KRISS 108-04-001 (oyster tissue) and 108-05-001 (water dropwort stem), were prepared by Korea Research Institute of Standards and Science (KRISS)during FY '01. The certified values of these materials had been determined by Isotope Dilution Mass Spectrometry (IDMS) for six elements (Cd, Cr, Cu, Fe, Pb and Zn). Additional analytical works are now progressing to certify the concentrations of a number of the environmental and nutrimental elements in these CRMs. The certified values in a CRM are usually determined by using a single primary method with confirmation by other method(s) or using two independent critically-evaluated methods. Instrumental Neutron Activation Analysis (INAA) plays an important role in the determination of certified values as it can eliminate the possibility of common error sources resulting from sample dissolution. In this study INAA procedure was used in determination of 23 elements in these two biological CRMs to acquire the concentration information and the results were compared with KRISS certified values.

• Analytical Science and Technology
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• v.19 no.2
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• pp.163-171
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• 2006

This study was performed to develop an analytical method in specified wastes for preventing the environmental pollution from hazardous wastes. Few analytical methods were developed using the waste standard reference materials of sludge, waste oil, bottom ash, etc. which contain As, CN, Cd, Cr, Cu, Pb, and Hg compounds. The pre-treatment method was considered by whether or not the synchronous analysis is possible. Waste samples obtained from the 34 representative facilities, which are emitting the hazardous substances, were analyzed.

• Analytical Science and Technology
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• v.15 no.6
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• pp.580-583
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• 2002

New approach is developed employing the overall uncertainty obtained from multiple measurements to evaluate the statistical significance for the difference between a given reference value and its measured value determined in a lab. The overall uncertainty is determined by separate combinations of the uncertainties arising from systematic and random effects. It is shown that the uncertainty term in regular t-test can be underestimated by n measurements.

• Mass Spectrometry Letters
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• v.11 no.4
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• pp.108-112
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• 2020

A certified reference material (CRM) for the analysis of nutrient elements in an edible mushroom (Ganoderma lyceum) powder has been developed (KRISS CRM 108-10-011). The mass fractions of calcium (Ca), iron (Fe), and zinc (Zn) were measured by isotope dilution inductively coupled plasma mass spectrometry (ID ICP/MS). To dissolve the fungi cell wall of mushroom consisted of chitin fibers, sample preparation method by single reaction chamber type microwave-assisted acid digestion with acid mixtures was optimized. The mean measurement results obtained from 12 sample bottles were used to assign as the certified values for the CRM and the between-bottle homogeneities were evaluated from the relative standard deviations. The certified values were metrologically traceable to the definition of the kilogram in the International System of Units (SI). This CRM is expected to be used for validation of analytical methods or quality control of measurement results in analytical laboratories when they determine the mass fractions of elements in mushroom or other similar samples.

• Analytical Science and Technology
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• v.27 no.6
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• pp.339-346
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• 2014

The author assessed the availability of urine reference material for proficiency test provided for laboratories in occupational health. N-methylacetamide is the biomarker of exposure to N,N-dimethyl acetamide, which was used as the substitute for hepatotoxic N,N-dimethylformamide (DMF). N-methylacetamide (NMAC) urine samples of 3 different levels covering the 0.2~2 times of the exposure limit were tested. Stability test up to 180 days (0, 7, 30, 60, 180 days) at 4 different temperatures (-60, -20, 5, $25^{\circ}C$) and homogeneity test were performed for these samples. New analytical condition by GC/MSD using SIM mode (m/z 58, 59) and DB-624 column was investigated for better selectivity, sensitivity and resolution. Urinary NMAC samples showed good homogeneity for 3 levels. These samples also showed good stability up to 180 days. The data of stability and homogeneity of urinary DMAC confirmed the basis of including this item into Korean proficiency test for occupational health laboratories since 2008.

• Analytical Science and Technology
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• v.13 no.2
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• pp.179-188
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• 2000

Trace elements in air samples artificially loaded on filters with urban dust and the bulk material of urban dust as an environmental sample were determined non-destructively using instrumental neutron activation analysis. Standard reference material (Urban Dust, SRM 1648) of the National Institute of Standard and Technology was used for the analytical quality control. The relative error for 37 elements was less than 15% and the standard deviation was less than 10%. 29 elements in the urban dust and 21 elements in the loaded filter sample were determined respectively. To evaluate the proficiency and reliability of the measurement, data intercomparison was performed and 39 analytical laboratories participated in the analysis using different analytical methods; neutron activation analysis, particle induced X-ray emission analysis, X-ray fluorescence analysis and atomic absorption spectrometry. Z-scores were calculated using the standard deviation of the laboratorie's mean as target standard deviation, and a good result was obtained that the values fall between -1 and +1 except some elements.

• Journal of Ginseng Research
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• v.37 no.4
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• pp.475-482
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• 2013

The main active components of Panax ginseng are ginsenosides. Ginsenoside Rb1 and Rg1 are accepted as marker substances for quality control worldwide. The analytical methods currently used to detect these two compounds unfairly penalize steamed and dried (red) P. ginseng preparations, because it has a lower content of those ginsenosides than white ginseng. To manufacture red ginseng products from fresh ginseng, the ginseng roots are exposed to high temperatures for many hours. This heating process converts the naturally occurring ginsenoside Rb1 and Rg1 into artifact ginsenosides such as ginsenoside Rg3, Rg5, Rh1, and Rh2, among others. This study highlights the absurdity of the current analytical practice by investigating the time-dependent changes in the crude saponin and the major natural and artifact ginsenosides contents during simmering. The results lead us to recommend (20S)- and (20R)-ginsenoside Rg3 as new reference materials to complement the current P. ginseng preparation reference materials ginsenoside Rb1 and Rg1. An attempt has also been made to establish validated qualitative and quantitative analytical procedures for these four compounds that meet International Conference of Harmonization (ICH) guidelines for specificity, linearity, range, accuracy, precision, detection limit, quantitation limit, robustness and system suitability. Based on these results, we suggest a validated analytical procedure which conforms to ICH guidelines and equally values the contents of ginsenosides in white and red ginseng preparations.