• Journal of Pharmaceutical Investigation
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• 제35권6호
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• pp.461-465
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• 2005

A simple HPLC method with ultraviolet detection of nicardipine in human plasma was developed and validated. After drug extraction with solid phase extraction (SPE) method, chromatographic separation of nicardipine in plasma was achieved at $30^{\circ}C$ with a $C_{18}$ column and acetonitrile-0.02% phosphate buffer mixture (with 0.02% triethylamine, final pH 7.0), as mobile phase. Quantitative determination was performed by ultraviolet detection at 254 nm. The method was specific and validated with a limit of quantification of 5 ng/mL. The intra- and inter-day precision and accuracy were acceptable for all quality control samples including the lower limit of quantification. The applicability of the method was demonstrated by analysis of plasma after oral administration of a single 40 mg dose to 8 healthy subjects. From the plasma nicardipine concentration versus time curves, the mean $AUC_{t}$, was $134.04{\pm}59.72\;ng\;hr/mL$ and $C_{max}$ of $108.65{\pm}69.17\;ng/mL$ reached 1.5 hr after administration. The mean biological half-life of nicardipine was $3.93{\pm}0.82\;hr$. Based on the results, this simple and validated assay method could readily be used in any pharmacokinetic or bioequivalence studies using human.

• Environmental Engineering Research
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• 제12권1호
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• pp.16-20
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• 2007

Toxicity of metal plating wastewater was evaluated by using acute toxicity tests on Daphnia magna. To identify toxicants of metal plating wastewater, several manipulations such as solid phase extraction (SPE), ion exchange and graduated pH adjustment were used. The SPE test had no significant effect on baseline toxicity, suggesting absence of toxic non-polar organics in metal plating wastewater. However, anion exchange largely decreased the baseline toxicity by 88%, indicating the causative toxicants were inorganic anions. Considering high concentration of chromium in metal plating wastewater, it is thought the anion is Cr(VI) species. Graduated pH test showing independence of the toxicity on pH change strongly supports this assumption. However, as revealed by toxicity confirmation experiment, the initial toxicity of metal plating wastewater (24-h TU=435) was not explained only by Cr(VI) (24-h TU = 725 at $280\;mg\;L^{-1}$). Addition of nickel($29.5\;mg\;L^{-1}$) and copper ($26.5\;mg\;L^{-1}$) largely decreased the chromium toxicity up to 417 TU, indicating antagonistic interaction between heavy metals. This heavy metal interaction was successfully predicted by an equation of 24-h $TU\;=\;3.67\;{\times}\;\ln([Cu]\;+\;[Ni])\;+\;79.44$ at a fixed concentration of chromium.

• 약학회지
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• 제54권4호
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• pp.226-231
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• 2010

Oral fluid has become increasingly popular as an alternative specimen in the field of driving under the influence of drugs (DUID) and work place drug testing. In this study, an analytical method for the detection and quantification of ${\Delta}^9$-tetrahydrocannabinol (THC) and its metabolite, 11-nor-9-carboxy-${\Delta}^9$-tetrahydrocannabinol (THC-COOH) in oral fluid by SPE and GC-MS was established and fully validated. The stability of THC and THC-COOH in oral fluid during storage was also determined by examining the THC and THC-COOH concentration changes depending on time and container materials. Oral fluid samples were kept over 21 days at room temperature, $-4^{\circ}C$ and $-20^{\circ}C$ in two different specimen collection tubes; glass and polypropylene tubes. Three replicates for each condition with different temperature and types of a container were analyzed at five different time points over 21 days. When oral fluid samples were stored in glass tubes, the loss of both THC and THC-COOH was less than 10% at all room temperature, $-4^{\circ}C$ and $-20^{\circ}C$. However, in polypropylene tubes, the loss of both THC and THC-COOH increased significantly over the study period. In particular, the concentration of THC decreased more rapidly than that of THC-COOH at room temperature and the maximal percentage of THC lost was 90.3% after 21 days. The result indicates that it would be necessary to collect oral fluid samples in glass containers and cool the samples until analysis in order to prevent the degradation of analytes.

• 한국환경농학회지
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• 제34권1호
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• pp.52-56
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• 2015

BACKGROUND: Three commercial biopesticides containing derris extract, which is permitted as a commercial biopesticide substances by the Environmentally-friendly Agriculture Promotion Act, have been marketed in Korea. But, the quantitative analytical method of active substances for crop protection in biopesticides containing derris extract has not known. METHODS AND RESULTS: Solid phase extraction (SPE) cartridge clean-up method for the quantitative analysis of rotenone and deguelin in biopesticides containing derris extract was developed and validated by ultra-performance liquid chromatography (UPLC). The clean-up method was established using hydrophilic lipophilic balance (HLB) SPE cartridges for the bioactive substances in biopesticides containing derris extract, and the eluate was analyzed to quantify the rotenone and deguelin by the UPLC. LOQ and recovery rates of rotenone and deguelin were 0.085 and 0.044 mg/L, 95.7 and 93.3%, respectively. The content of rotenone and deguelin in three biopesticides containing derris extract were analyzed by the developed method, the results showed 0.001-0.236 and

• Food Science and Biotechnology
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• 제18권4호
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• pp.842-848
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• 2009

The purpose of this study was to determine the extent of domoic acid (DA) a potent neurotoxin, responsible for the syndrome amnesic shellfish poisoning (ASP) contamination of various species of bivalve shellfish purchased from fish market in Korea and the implications for food safety. Liquid chromatography (LC) methods were applied to quantify DA in shellfish after sample clean-up using solid-phase extraction (SPE) with strong anion exchange (SAX) cartridges. Toxin detection was achieved using photodiode array ultraviolet (LC-UV) and electrospray ionization-mass (LC-ESI-MS). DA was identified in 4 bivalve shellfishes of 872 shellfishes collected from March, 2006 to October, 2007 in Korea. DA amount of 3 surf clams (Mactra veneriformis) collected at Seoul, Daejeon, and Daegu were 4.13, 1.99, and 1.94 mg/kg, respectively. DA amount of 1 pink butterfly shell (Peronidia venulosa) collected at Seoul was 3.02 mg DA/kg. The amounts of DA that were present in 4 bivalve shellfishes were within EU guideline limits for sale of shellfish (20 mg DA/kg).

• Environmental Engineering Research
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• 제13권4호
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• pp.216-223
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• 2008

An efficient method for the simultaneous determination of eleven phenolic endocrine-disrupting chemicals (EDCs) present in wastewater influent samples was described. The 11 phenolic EDCs including alkylphenols, chlorophenols, and bisphenol A were determined by gas chromatography/mass spectrometry-selected ion monitoring (GC/MS-SIM) following two work-up methods for comparison; isobutoxycarbonyl (isoBOC) derivatization and tert-butyldimethylsilyl (TBDMS) derivatization. The wastewater influent samples containing the 11 EDCs were adjusted to pH 2 with $H_2SO_4$ and then cleaned up with n-hexane. Next, they were subjected to solid-phase extraction (SPE) with XAD-4 resin and subsequently converted to isoBOC or TBDMS derivatives for sensitivity analysis with gas chromatography/mass spectrometry-selected ion monitoring (GC/MSSIM). Following isoBOC derivatization and TBDMS derivatization, the recoveries were 86.6-105.2% and 97.6-142.7%, the limits of quantitation (LOQ) for the 11 phenolic EDCs for SIM was 0.001-0.050 ng/mL and 0.003-0.050 ng/mL, and the SIM responses were linear with the correlation coefficient varying by 0.9717-0.9995 and 0.9842-0.9980, respectively. When these methods were applied to five selected wastewater influent samples, for isoBOC derivatization and TBDMS derivatization the ranges of concentration detected were 0.2-99.6 ng/mL and 0.4-147.4 ng/mL, respectively.

• Environmental Analysis Health and Toxicology
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• 제18권1호
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• pp.45-55
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• 2003

The alkylphenols, chlorophenols and bisphenol A were determined by gas chromatography/mass spectrom-etry-selected ion monitoring (GC/MS-SIM) mode followed by two work-up methods for comparison; isoBOC derivatization method and TBDMS derivatization method. Eleven phenols in paper samples were extracted with acetonitrile. Also, solid -phase extraction (SPE) with XAD -4 and subsequent conversion to isobutoxycarbonyl derivatives or tert.-butyldimethylsilyl derivatives for sensitive analysis with the selected ion-monitoring (SIM) mode. The SIM responses were linear with the correlation coefficient varying 0.9717 ∼ 0.9995 (isoBOC derivatization), and 0.9842 ∼ 0.9980 (TBDMS derivatization). The recoveries were 82.4 ∼ 108.8％) by area ratio of phenanthrene -d$\_$10/ vs bisphenol A-d$\^$l6/. (isoBOC derivatization and TBDMS derivatization) The range of concentrations was respectively, 0.95 ∼ 1.44 ng/g in 2,4-dichlorophenol, 1.01 ∼ 1.17 ng/g in t-butylphenol,2.17 ∼ 5.84 ng/g in pentachlorophenol, 12.68 ∼ 14.88 ng/g in nonylphenol and 30.84 ∼ 153.72 ng/g in bisphenol A.

• Environmental Analysis Health and Toxicology
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• 제17권1호
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• pp.37-51
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• 2002

Eleven phenols including two chlorophenols, eight alkylphenols and bisphenol A were derivatized with isobutylchloroformate to form their isobutoxycarbonyl derivatives. Standard phenol mixture was concentrated for the isobutoxycarbonyl (isoBOC) derivatization and analysed by gas chromatography/mass spectrometry (GC/MS). The recoveries of the derivatization method of alkylphenols, chlorophenols, and bisphenol A were calculated by gas chromatography/mass spectrometry-selected ion monitoring mode using two work-up methods for comparison; shaking and heating method. The linear detector responses were obtained in the concentration range of 5∼400 ng, with correlation coefficients varying from 0.9755∼0.9981. Recoveries of the alkylphenols, chlorophenols, and bisphenol A were determined by gas chromatography/mass spectrometry-selected ion monitoring mode using two work-up methods for comparison ; the US-EPA method and the isoBOC derivatization method, Eleven phenols in water samples were extracted with dichloromethane and then concentrated. Also, solid-phase extraction (SPE) with XAD-4 and subsequent conversion to isobutoxycarbonyl derivatives for sensitive analysis with the selected ion-monitoring (SIM) mode. The recoveries were 85.1∼109.9％ and 90.3∼126.6％ for the US-EPA method and the isoBOC.

• 분석과학
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• 제28권1호
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• pp.17-25
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• 2015

A rapid, sensitive and specific method was developed and validated using electrospray ionization (ESI) tandem mass spectrometry (LC-MS/MS) for determination of misoprostol acid in human plasma. Misoprostol $acid-d_5$ was used as in internal standard (IS). The analyte and IS were extracted by simple one step solid phase extraction (SPE). Linearity in plasma was obtained over the concentration range 10~3000 pg/mL and lower limit of quantification (LLOQ) was identifiable and reproducible at 10 pg/mL. The intra- and inter-day precision values were below 9% and the accuracy was ranged from 93.81% to 102.02% at all four quality control samples. The method was has been successfully applied for routine assay to support pharmacokinetic study of misoprostol acid in human plasma after an oral administration of 0.4 mg misoprostol.

• Archives of Pharmacal Research
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• 제26권9호
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• pp.697-705
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• 2003

The alkylphenols, chlorophenols, and bisphenol A were determined by gas chromatography/mass spectrometry-selected ion monitoring (GC/MS-SIM) followed by two work-up methods for comparison: isobutoxycarbonyl (isoBOC) derivatization and tert-butyldimethylsilyl (TBDMS) derivatization. Eleven endocrine disrupting chemicals (EDCs) of phenols in biological samples were extracted with acetonitrile and then the acetonitrile layer underwent freezing filtration 6$0^{\circ}C$ for 2 hours. Solid-phase extraction (SPE) was used with XAD-4 and subsequent conversion to isoBOC or TBDMS derivatives for sensitivity analysis with the GC/MS-SIM mode. For isoBOC derivatization and TBDMS derivatization the recoveries were 92.3∼150.6% and 93.8∼108.3%, the method detection limits (MDLs) of bisphenol A for SIM were 0.062 $\mu$ g/kg and 0.010 $\mu$ g/kg, and the SIM responses were linear with the correlation coefficient varying by 0.9755∼0.9981 and 0.9908∼0.9996, respectively. When these methods were applied to mackerel samples, the concentrations of the 11 phenol EDCs were below the MDL.