• Mass Spectrometry Letters
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• v.12 no.1
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• pp.1-10
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• 2021

A simple, specific, and economical LC-MS/MS method was investigated for the screening of 43 prescribed antihypertensive and related drugs in human urine. The urine samples were simply prepared by diluting and mixing with internal standard before directly introduced to the LC-MS/MS system, which is fast, straightforward, and cost-effective. Fractional factorial, Box-Behnken, and I-optimal design were applied to screen and optimize the mass spectrometric and chromatographic factors. The analysis was carried out on a triple quadrupole mass spectrometer system utilizing multiple reaction monitoring with positive and negative electrospray ionization method. Chromatographic separation was performed on a Thermo Scientific Accucore RP-MS column (50 × 3.0 mm ID., 2.6 ㎛) using two separate gradient elution programs established with the same mobile phases. Chromatographic separation was performed within 12 min. The optimal method was validated based on FDA guideline. The results indicated that the assay was specific, reproducible, and sensitive with the limit of detection from 0.1 to 50.0 ㎍/L. The method was linear for all analytes with coefficient of determination ranging from 0.9870 to 0.9981. The intra-assay precision was from 1.44 to 19.87% and the inter-assay precision was between 2.69 and 18.54% with the recovery rate ranges from 84.54 to 119.78% for all drugs measured. All analytes in urine samples were stable for 24 h at 25℃, and for 2 weeks at -60℃. The developed method improves on currently existing methods by including larger number of cardiovascular medications and better sensitivity of 12 analytes.

• Proceedings of the Korea Society of Environmental Toocicology Conference
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• 2004.05a
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• pp.73-73
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• 2004

• Journal of Environmental Science International
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• v.10 no.6
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• pp.445-450
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• 2001

This study was carried out In Investigate the correlation between toluene In air and hippuric acid In human urine, which 1.: based on the results of the health check-in and the measure of working environment, was investigated for two years. The concentration of toluene in air for the five working places in Yang-San area were ranged from 39.05±10.31 ppm to 4.04±3.38ppm and the mean value of those was 16.89±14.76ppm. The mean value was 16.89±14.76ppm which is below the permissible limit of toluene. The concentration of hippuric acid(HA) In the worker's urine were between 0.47g/ℓ and 0.76g/ℓ. There was mutual correlation (Υ=0.94) between the concentration of toluene in air and that of hippuric acid in urine. In case of male workers, the mean value of hippurlc acid In urine was 0.56g/ f and the female workers was 0.57g/ℓ that showed higher than the male's. However, there was no relationship between the workshop and the distinction of sex. From the mean value of toluene in air(T) and that of hippuric acid(H), we obtained the formula, Η=0.3logΤ+0.235.

• Carbon letters
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• v.26
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• pp.43-50
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• 2018

In this research, a novel and efficient quinoline thioacetamide functionalized magnetic graphene oxide composite ($GO@Fe_3O_4@QTA$) was synthesized and utilized for dispersive magnetic solid phase preconcentration of Cd(II) and Ni(II) ions in urine and various food samples. A number of diverse methods were employed for characterization of the new nanosorbent. The design of experiments approach and response surface methodology were applied to monitor and find the parameters that affect the extraction performance. After sorption and elution steps, the concentrations of target analytes were measured by employing FAAS. The highest extraction performance was achieved under the following experimental conditions: pH, 5.8; sorption time, 6.0 min; $GO@Fe_3O_4@QTA$ amount, 17 mg; 2.4 mL $1.1mol\;L^{-l}$ $HNO_3$ solution as the eluent and elution time, 13.0 min. The detection limit is 0.02 and $0.2ng\;mL^{-1}$ for Cd(II), and Ni(II) ions, respectively. The accuracy of the new method was investigated by analyzing two certified reference materials (sea food mix, Seronorm LOT NO 2525 urine powder). The interfering study revealed that there are no interferences from commonly occurring ions on the extractability of target ions. Finally, the new method was satisfactorily employed for rapid extraction and determination of target ions in urine and various food samples.

• Bulletin of the Korean Chemical Society
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• v.31 no.4
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• pp.845-849
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• 2010

A gold nanoparticles modified carbon paste electrode (GN-CPE) has been used for the determination of atenolol (ATN) in drug formulations by cyclic voltammetry (CV), differential pulse voltammetry (DPV) and chronocoulometric methods. The results revealed that the modified electrode shows an electrocatalytic activity toward the anodic oxidation of atenolol by a marked enhancement in the current response in buffered solution at pH 10.0. The anodic peak potential shifts by -80.0 mV when compared with the potential using bare carbon paste electrde. A linear analytical curve was observed in the range of $1.96\;{\times}\;10^{-6}$ to $9.09\;{\times}\;10^{-4}\;mol\;L^{-1}$. The detection limit for this method is $7.3\;{\times}\;10^{-8}\;mol\;L^{-1}$. The method was then successfully applied to the determination of atenolol in tablets and human urine. The percent recoveries in urine ranged from 92.0 to 110.0%.

• Bulletin of the Korean Chemical Society
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• v.35 no.4
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• pp.1133-1138
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• 2014

Ultrahigh performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UPLC-ESI- MS/MS) provides a high-speed method to screen a large number of samples for small molecules with specific properties. In this study, UPLC-ESI-MS/MS with multiple reaction monitoring (MRM) was employed to screen urinary phospholipid (PL) content for biomarkers of prostate cancer. From lists of urinary PLs structurally identified using nanoflow LC-ESI-MS/MS, 52 PL species were selected for quantitative analysis in urine samples between 22 cancer-free urologic patients as controls and 45 prostate cancer patients. Statistical treatment of data by receiver operating characteristic (ROC) analysis yielded 14 PL species that differed significantly in relative concentrations (area under curve (AUC) > 0.8) between the two groups. Among PLs present at higher levels in prostate cancer urine, phosphatidylcholines (PCs) and phosphatidylinositols (PIs) constituted the major head group PLs (3 PCs and 7 PIs). For technical reasons, PL species of low abundance may be underrepresented in data from UPLC-ESI-MS/MS performed in MRM mode. However, the proposed method enables the rapid screening of large numbers of plasma or urine samples in the search for biomarkers of human disease.

• Journal of The Korean Society of Clinical Toxicology
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• v.2 no.1
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• pp.45-48
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• 2004

Paraquat, a widely used herbicide, is extremely toxic, causing multiple organ failure in human. Many treatment modality has been used, but now paraquat is very fatal drug. Elimination rate of plasma paraquat seems to be a factor for the survival rate. So early diagnosis and early treatment are very important. Plasma paraquat concentration could be measured by radioimmunoassay. But it is impossible that the test was done at Emergency room and the result was checked immediately. There was relation between plasma paraquat concentrations and urine paraquat concentration. Because of its simplicity and low cost, urine paraquat concentration test is complementary to the plasma concentration measurement. If the patient has psychotic problem or unconscious mental state, and is observed unexplained dyspnea and oral ulcer, urine paraquat test is very important to rule out acute paraquat intoxication. We experienced a patient who was presented as unexplained acute renal failure initially and was diagnosed as paraquat intoxication later.

• Analytical Science and Technology
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• v.20 no.4
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• pp.315-322
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• 2007

This study has been described the metabolism and excretion in a healthy male urine collected for 24 hr after oral administration of a complex (pseudoephedrine and dextromethorphan). To detect the trace amounts of parent drugs and their metabolites, acid-hydrolyzed urine was extracted and derivatized with MSTFA and MBTFA followed by gas chromatography/mass spectrometric analysis. Two parent drugs and their metabolites were tentatively identified as their derivatives based on the mass spectral interpretation and compared with previous reports. In addition, the time profile of urinary excretion rate for parent drugs and metabolites was studied. On the basis of metabolites identified and excretion rate, the metabolic pathways of both drugs are suggested.

• Molecules and Cells
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• v.41 no.3
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• pp.179-187
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• 2018

Proteomic analysis of extracellular vesicles (EVs) from biological fluid is a powerful approach to discover potential biomarkers for human diseases including cancers, as EV secreted to biological fluids are originated from the affected tissue. In order to investigate significant molecules related to the pathogenesis of bladder cancer, EVs were isolated from patient urine which was analyzed by mass spectrometry based proteomics. Comparison of the EV proteome to the whole urine proteome demonstrated an increased number of protein identification in EV. Comparative MS analyses of urinary EV from control subjects and bladder cancer patients identified a total of 1,222 proteins. Statistical analyses provided 56 proteins significantly increased in bladder cancer urine, including proteins for which expression levels varied by cancer stage (P-value < 0.05). While urine represents a valuable, non-invasive specimen for biomarker discovery in urologic cancers, there is a high degree of intra- and inter-individual variability in urine samples. The enrichment of urinary EV demonstrated its capability and applicability of providing a focused identification of biologically relevant proteins in urological diseases.

• Analytical Science and Technology
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• v.13 no.3
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• pp.385-393
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• 2000

A gas chromatography-mass spectrometric (GC/MS) procedure for the determination of amineptine (dihydro-10, 11-dibenzo[a, d] cycloheptenyl-5-amino-7-heptanoic acid) and its main metabolites in human urine was described. Amineptine has been known to be extensively metabolized by the ${\beta}$-oxidation of the heptanoic side chain with formation of pentanoic side chain metabolite ($C_5$-metabolite), and lactamizarion by internal dehydration of (${\beta}$-oxidized metabolite (${\delta}$-lactam). The detection of these compounds was based on acid hydrolysis, liquid-liquid extraction and trimethylsilylated derivatization of the carboxylic acid group. For the determination of amineptine and its metabolites in biological fluids, selected ions at the m/ 192, molecular ion and one of the characteristic ions were monitored by GC/MS. On the excretion study of amineptine in human urine, 70-90% of amineptine, ${\delta}$-lactam, and $C_5$-metabolite were found to be excreted within 4 hours and their excretion completed within 20 hours.