• Proceedings of the PSK Conference
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• 2002.10a
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• pp.297.1-297.1
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• 2002

Immunoassays are frequently used for an screening method to detect the presence of drugs in Urine. The main advantages of the method are well known -- simplicity of handling samples. rapidity. sensitivity. and specificity of analysis. However. it is also known that immunoassays exhibit cross-reactivity to related drugs and there are only limited specific immunoassays on the market. This study reports on the ability of TDx to detect urine samples obtained from suspects of taking over-the-counter medications and illegal drugs containing ATS. designer drugs. (omitted)

• Analytical Science and Technology
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• v.19 no.1
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• pp.103-106
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• 2006

A 35-year-old Perubian who suffered from grand mal seizures died in the aircraft on his way from the United States to Hongkong via Incheon international airport of Korea. While performing the autopsy, 115 packs made with double layer of transparent film and black plastic bag containing cocaine were found in the ileum and large intestine. Among of them, 3 packs were ruptured. To determine the concentration of cocaine and its metabolites, blood, urine, bile, liver, spleen, heart, kidney, brain and gastric contents were taken and toxicological analysis was performed. Gas chromatography/mass spectrometry (GC/MS) following liquid-phase extraction using chloroform:isopropanol (=9:1) and derivatization with bis(trimethylsilyl)-trifluoroacetamide (contains 1% trimethylchlorosilane) was performed. High levels of cocaine, benzoylecgonine (BE) and ecgonine methylester (EME) were found in the postmortem blood (0.96, 3.09 and $5.59{\mu}g/mL$) and urine (32.85, 145.35 and $53.17{\mu}g/mL$), respectively. Cocaine and its metabolites were also detected in all other biological specimen.

• Journal of Radiation Industry
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• v.18 no.2
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• pp.101-107
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• 2024

Rapid screening for internal contamination by alpha- and beta-emitting radionuclides is essential in situations involving radiation workers or radiation accidents. This study focused on the use of urine samples and liquid scintillation counting to quickly and accurately assess contamination. Calibration of the alpha and beta detection areas ensured precise measurement results. The major radionuclides recommended for surveillance during accidents were also considered. This study evaluated the effectiveness of the method by examining various parameters, including the limit of detection, linearity, sensitivity, selectivity, accuracy, ruggedness, and blind test sample analysis. The liquid scintillation counting method is an effective tool for screening urinary samples to detect alpha- and beta-emitting radionuclides, particularly during radiation emergencies, despite some limitations in precision.

• Bulletin of the Korean Chemical Society
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• v.34 no.4
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• pp.1131-1136
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• 2013

Parabens, the esters of p-hydroxybenzoic acid, have been widely used as antimicrobial preservatives in cosmetic products, drugs, and processed foods and beverages. However, some parabens have been shown to have weak estrogenic effects through in vivo and in vitro studies. Because such widespread use has raised concerns about the potential human health risks associated with exposure to parabens, we developed a simultaneous analytical method to quantify 4 parabens (methyl, ethyl, propyl, and butyl) in human urine, by using solid-phase extraction and high-performance liquid chromatography coupled with triple quadrupole mass spectrometry. This method showed good specificity, linearity ($R^2$ > 0.999), accuracy (92.2-112.4%), precision (0.9-9.6%, CV), and recovery (95.7-102.0%). The LOQs for the 4 parabens were 1.0, 0.5, 0.2, and 0.5 ng/mL, respectively. This method could be used for quick and accurate analysis of a large number of human samples in epidemiological studies to assess the prevalence of human exposure to parabens.

• Proceedings of the Korea Society of Environmental Toocicology Conference
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• 2000.12a
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• pp.64-64
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• 2000

• Proceedings of the PSK Conference
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• 2000.04a
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• pp.124.1-124.1
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• 2000

• Analytical Science and Technology
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• v.13 no.2
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• pp.258-267
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• 2000

The result of five year's experience on Inter-laboratory Comparison for Analyses of Heavy Metals and Organic Solvent Metabolites in Biological Samples was described. Since 1995, around a hundred laboratories in the Occupational Health have participated this program twice per year by the Industrial Safety and Health Law. Four metals in blood and five organic solvent metabolites in urine were examined. Reference samples were made by spiking standard materials to human blood or urine pools treated previously to give homogeneity and stability for a specific time periods. Some reference samples for organic solvent metabolites were made from workers' urine who were exposed to the organic solvents. Some items such as Lead in blood and Hippuric acid in urine showed good accordance between participants while the other items such as Mercury and N-methylformamide in urine showed poor proficient rate. The results were published in the internet or newspaper to help the consumer of the laboratory's service to get the information on them and to make competition between them. The inter-laboratory's comparison program have done greate role to improve the ability of analysis and reliability of analytical data produced from each laboratory.

• Environmental Analysis Health and Toxicology
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• v.17 no.3
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• pp.197-205
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• 2002

Volatile organic compounds (VOCs) are an important public health problem throughout the world. Many important questions remain to be addressed in assessing exposure to these compounds. Because they are ubiquitous and highly volatile, special techniques must be applied in the analytical determination of VOCs. Personal exposure measurements are needed to evaluate the relationship between microenvironmental concentrations and actual exposures. It is also important to investigate exposure frequency, duration, and intensity, as well as personal exposure characteristics. In addition to air monitoring, biological monitoring may contribute significantly to risk assessment by allowing estimation of absorbed doses, rather than just the external exposure concentrations, which are evaluated by environmental and personal monitoring. This study was conducted to establish the analytic procedure of VOCs in air, blood, urine and exhaled breath and to evaluate the relationships among these environmental media. The subjects of this study were selected because they are occupationally exposed to high levels of VOCs. Environmental, personal, blood, urine and exhalation samples were collected. Purge ＆ trap, thermal desorber, gas chromatography and mass selective detector were used to analyze the collected samples. Analytical procedures were validated with the“break through test”, 'quot;recovery test for storage and transportation”,“method detection limit test”and“inter-laboratory QA/QC study”. Assessment of halogenated compounds indicted that they were significantly correlated to each other (p value < 0.01). In a similar manner, aromatic compounds were also correlated, except in urine sample. Linear regression was used to evaluate the relationships between personal exposures and environmental concentrations. These relationships for aromatic and halogenated are as follows: Halogen $s_{personal}$ = 3.875+0.068Halogen $s_{environmet}$, ($R^2$= .930) Aromatic $s_{personal}$ = 34217.757-31.266Aromatic $s_{environmet}$, ($R^2$= .821) Multiple regression was used to evaluate the relationship between exposures and various exposure deter-minants including, gender, duration of employment, and smoking history. The results of the regression model-ins for halogens in blood and aromatics in urine are as follows: Halogen $s_{blood}$ = 8.181+0.246Halogen $s_{personal}$+3.975Gender ($R^2$= .925), Aromatic $s_{urine}$ = 249.565+0.135Aromatic $s_{personal}$ -5.651 D.S ($R^2$ = .735), In conclusion, we have established analytic procedures for VOC measurement in biological and environmental samples and have presented data demonstrating relationships between VOCs levels in biological media and environmental samples. Abbreviation GC/MS, Gas Chromatography/Mass Spectrometer; VOCs, Volatile Organic Compounds; OVM, Organic Vapor Monitor; TO, Toxic Organicsapor Monitor; TO, Toxic Organics.

• Analytical Science and Technology
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• v.21 no.6
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• pp.510-517
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• 2008

This study has been described the metabolism and excretion in a healthy male urine collected for 26hrs after oral administration of diclofenac. To detect conjugated metabolites of diclofenac, urine sample was acid-hydrolyzed under the conditions of 6M-HCl at over $110^{\circ}C$ for 1hr. During the acidic hydrolysis process, diclofenac and its metabolites were converted into their corresponding lactam-ring through dehydration reaction. As results of chemical conversion by means of hydrolysis, the structures of diclofenac and its metabolites were also changed acidic to basic forms. However, lactam-ring was degraded by hydroxyl ion at basic condition. Thus, the extraction rate of dehydrated diclofenac and its metabolites was not favored at basic condition. For the determination of trace amounts of diclofenac and its metabolites in urine, trimethylsilylation (TMS) with MSTFA was applied and followed by analysis with gas chromatograph-mass spectrometer. In this study, four metabolites that are formed by the hydroxylation of parent drug were mainly detected. Each metabolite was tentatively identified by both interpretation of mass spectra and comparison with previously reported results. In addition, time profile of urinary excretion rate for parent drugs and metabolites was studied. Finally, the metabolic pathway of diclofenac was suggested on the basis of the elucidation of its metabolites and excretion profiles.

• Journal of Veterinary Clinics
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• v.40 no.6
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• pp.399-407
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• 2023

Chronic kidney disease (CKD) occurs in more than 15% of the dogs over 10 years of age and causes irreversible renal function deterioration. Therefore, it is important to diagnose CKD early and treat the disease properly. The purpose of this study aimed to to evaluate the clinical utility of urine albumin/creatinine ratio (ACR) using POC (point-of-care) device as an early detection urinary biomarker in CKD dogs and to confirm the correlation between ACR and other known CKD biomarkers. Urine and serum samples were obtained from 50 healthy dogs and 50 dogs with CKD. Serum blood urea nitrogen (BUN), creatinine, and symmetric dimethylarginine (SDMA) concentrations, and urine protein creatinine ratio (UPC) were measured. Urine specific gravity (USG) was evaluated using refractometer, and ACR was measured using an i-SENS A1Care analyzer. The ACR values of dogs with CKD were significantly different from those of healthy dogs (p < 0.001), as with other renal biomarkers. ACR showed significant differences between healthy dogs and dogs with CKD at every IRIS stage (p < 0.005), whereas no significant differences were observed between dogs with CKD IRIS stage I and healthy dogs with UPC. There are significant positive correlation between ACR and BUN (r = 0.611, p < 0.001), creatinine (r = 0.788, p < 0.001), SDMA (r = 0.747, p < 0.001), and UPC (r = 0.784, p < 0.001), and significant negative correlation between ACR and USG (r = -0.700, p < 0.001). In receiver operator characteristic curve analysis, the area under the curve (AUC) was 0.982 (95% CI 0.963-1.000, p < 0.001), with an optimal cut-off value of 64.20 mg/g (94% sensitivity and 94% specificity). Thus, ACR is a useful urinary biomarker for the early diagnosis of proteinuria in CKD and combined use of ACR and other renal biomarkers may be helpful for early diagnosis and prevention of CKD in dogs.