• Journal of Convergence for Information Technology
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• v.11 no.2
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• pp.107-116
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• 2021

In this study, an analytical method was developed for estradiol-17��, testosterone, and progesterone, which are growth promoters as veterinary drug residues in animal food. The analytes were separated using liquid chromatography, and was injected into a mass spectrometer through the electrospray ionization(ESI) process and detected in multiple reaction monitoring(MRM) mode. As the method was validated by CODEX CAC/GL 71-2009 guideline, it met the acceptable. The analysis of beef, pork, and chicken distributed in Korea was conducted with an established method to confirm the applicability of the actual sample. It was confirmed that the developed method can be quickly and reliably in the analysis for the growth promoters identified in domestic distributed livestock products. Through subsequent research, a highly utilized analysis method will be completed if the number of growth promoters is expanded based on the method and the simultaneous analytical method is established by including all of it.

• Analytical Science and Technology
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• v.18 no.4
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• pp.271-277
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• 2005

Urea in blood has been measured as an effective marker for diagnosis of renal function. Urea which is e end-product of nitrogen containing metabolites such as proteins is filtered through glomeruli of kidneys and then excreted as urine. If the renal function is deteriorated, the urea concentration in blood will be increased, from which the healthiness of renal function is judged. In order to improve the confidence of diagnosis results, the results must keep traceability chain to certified reference materials, which was certified by primary reference method. In this study, we proposed isotope dilution-liquid chromatography/mass spectrometry (ID-LC/MS) as a candidate primary method, in which $15^N_2$-urea is used as an internal reference material. The developed method is highly accurate in principle and is convenient as it does not require cumbersome derivatization. 0.1 mmol/L ammonium chloride was selected as a mobile phase for HPLC because it provided low interference in MS analysis of relatively low molecular weighted urea. HPLC and MS were connected with an electrospray ionization (ESI) interface of positive mode, which provided high sensitivity and reproducibility. The developed method was validated with internationally recognized reference materials, and we have obtained satisfactory results in an international ring trial. The expanded uncertainty calculated according to ISO guide was 1.8% at 95% confidence interval. The developed method is being used as a primary reference measurement method such as for certification of serum certified reference materials (CRMs).

• Analytical Science and Technology
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• v.34 no.6
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• pp.259-266
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• 2021

Cannabis (Marijuana) is one of the most widely used drugs in the world, and its distribution has been controlled in South Korea since 1976. Identification of 11-nor-Δ⁹-carboxy-tetrahydrocannabinol (THCCOOH) in urine can provide important proof of cannabis use, and it is considered scientific evidence in the forensic field. In this study, we describe a simultaneous quantitative method for identifying THCCOOH and THCCOOH-glucuronide in urine, using simple liquid-liquid extraction (LLE), and liquid chromatography-tandem mass spectrometry (LC-MS/MS). THCCOOH-D₃ and THCCOOH-glucuronide-D₃ were used as internal standards. Validation results of the matrix effect, as well as recovery, linearity, precision, accuracy, process efficiency, and stability were all satisfactory. No carryover, endogenous or exogenous interferences were observed. The limit of detection (LOD) of THCCOOH and THCCOOH-glucuronide were 0.3 and 0.2 ng/mL, respectively. The developed method was applied to 28 authentic human urine samples that tested positive in immunoassay screening and gas chromatography/mass spectrometry (GC/MS) tests. The ranges of concentrations of THCCOOH and THCCOOH-glucuronide in the samples were less than LOQ~266.90 ng/mL and 6.43~2133.03 ng/mL, respectively. The concentrations of THCCOOH-glucuronide were higher than those of THCCOOH in all samples. This method can be effectively and successfully applied for the confirmation of cannabinoid use in human urine samples in the forensic field.

• The Korean Journal of Food And Nutrition
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• v.19 no.3
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• pp.267-270
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• 2006

In Korea, for a long time Rhus verniciflua has traditionally been used as an herbal medicines plants. A stem of Rhus verniciflua has been used to treat gastrointestinal trouble with in form of boiled chicken as a folk medicine. But it has been recognized as an extremely active allergen causing skin reactions. The chief allergenic component, urushiol, is found within the oleoresinous sap of Rhus verniciflua. Most components of urushiol have unsaturated side chains. These unsaturated side chains of urushiol are important to polymerization of these natural products. The urushiol components in Korean lacquer were isolated by reversed phase HPLC. The molecular weight of purified urushiol was determined as 340 from mass analysis. This compound was identified as Heptadecatetraenyl catechol (MW 340).