• Analytical Science and Technology
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• v.25 no.1
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• pp.19-24
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• 2012

Liquid chromatography-tandem mass spectrometry (LC-MS/MS) method has been developed and validated for the quantitative determination of ertapenem in human plasma and urine. After addition of internal standard (ceftazidime), plasma and urine was diluted with methanol and analyzed by LC-MS/MS. Using MS/MS with multiple reaction monitoring (MRM) mode, ertapenem were selectively detected without severeinterference from human plasma and urine. The standard calibration curve for ertapenem was linear ($r^2$= 0.9996)over the concentration range 1~100 ${\mu}g/mL$ in human plasma. The intra- and inter-day precision over the concentration range of ertapenem was lower than 8.9% (correlation of variance, CV), and accuracy was between 97.2~106.2%. On the other hand, it was showed good relationship ($r^2$= 0.9992) and the precision (intra- and inter-day) over the concentration range of ertapenem was lower than CV 7.2%, and accuracy was between 97.9~111.6% for urine. This method has been successfully applied to the pharmacokinetic study of ertapenem in human plasma and urine.

• Korean Journal of Food Science and Technology
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• v.53 no.1
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• pp.72-77
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• 2021

Silkworms have traditionally been used to produce silk and textiles. However, steamed and freeze-dried mature silkworm larval powder (SMSP) contain large amounts of amino acids, vitamins, and essential minerals. In this study, we investigated the potential of SMSP as a hangover-relieving agent. Thirty individuals who met the selection criteria and exclusion criteria were included in the study and subsequently underwent a double-blind, randomized, placebo-controlled, cross-design human application test. Importantly, the test product containing SMSP (CKDHC) was proven to alleviate hangovers through a significant reduction in the plasma concentration of acetaldehyde in the context of an alcohol-induced hangover model. In particular, from 0.5 h after SMSP intake, the blood acetaldehyde concentration (mg/L), area under the time curve (AUC; indicating the degree of bioabsorption of blood acetaldehyde), and the highest blood acetaldehyde concentration (Cmax) were reduced. Altogether, these results suggest that the test product (CKDHC) exhibits an accelerated hangover-relieving effect.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.315-315
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• 2018

L-THIA ACN-WQ 2016 모형 개선 연구에서는 침투량 산정, 다중 기상지점 등 유역 규모 확대를 목적으로 엔진 개선과 모형의 최적 매개변수 선정을 위해 최적화 알고리즘을 활용한 자동보정 모듈을 개발하였다. 개선된 침투량 초기손실 산정 계수를 적용한 침투량 산정 방법을 Green-Ampt 모형의 침투량 산정 결과와 비교한 결과 편차는 매우 작았으며, Green-Ampt 모형을 통해 산정된 침투량 범위 내에 분포되어 개선된 침투량 산정 방법의 결과가 유효한 값을 의미하는 것으로 나타났다. 이렇게 도출된 초기손실 산정 계수를 관계식으로 개발하여 L-THIA ACN-WQ 2018 모형 내에서 CN에 따른 초기손실량이 산정되도록 하였고, 이를 기반으로 침투량 및 기저유출량이 산정된다. 유역 규모 확대를 위해 다중 기상지점이 적용되도록 엔진 코드를 개선하였으며, 평창A와 고부A 유역을 대상으로 단일 기상지점과 다중 기상지점 적용에 따른 유출 해석을 유량지속곡선을 통해 비교 한 결과 다중 기상지점 적용에 따라서 평창A와 고부A 유역 모두 유황구간이 크게 달라지는 것으로 나타났다. 특히 고부A 유역은 우황 변동 특성이 크게 나타났는데, 지역적 강우 특성이 뚜렷한 유역에서는 유출해석에 매우 중요한 영향인자로 작용되는 것으로 알 수 있었다. 마지막으로 L-THIA ACN-WQ 2018모형을 이용함에 있어 유역 특성에 알맞은 최적 매개변수 산정을 위해 유량 및 TN, TP 자동보정 툴을 개발하였다. 자동보정툴은 2개의 보정방안으로 개발하였다. 첫 번째는 유역 전체에 대해 하나의 최적매개변수를 도출하는 것이며, 두번째는 유역 내 다중 보정 지점을 통해 소유역별 최적매개변수를 도출하는 것이다. 이를 통해 사용자는 모형의 활용 목적 및 가용 가능한 보정 자료 등을 고려하여 모형의 최적 매개변수를 도출할 수 있다. 이렇게 개선된 L-THIA ACN-WQ 2018 모형을 총량단위유역 한강 평창A와 금강 고부A에 적용한 결과 유량은 NSE 0.76, 0.85로 매우 높게 나타났으며, TN, TP의 NSE는 0.64 ~ 0.86 로 매우 높은 적용성 결과가 도출되었다. Ryu(2016)의 연구 결과와 비교해보면 평창A는 NSE와 $R^2$ 수치로는 큰 차이를 보이지 않았지만, 유량 모의에서 일별 예측값 변화 폭에 큰 변화가 있는 것으로 나타났다. 기존 L-THIA ACN-WQ 2016모형 결과에서는 일별 유량의 변동성이 매우 크지만, L-THIA ACN-WQ 2018 모형에서는 일별 유량 변동폭이 크게 감소하여, 유량 모의에 큰 개선 효과가 있는 것으로 나타났다

• The Korean Journal of Pesticide Science
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• v.19 no.3
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• pp.317-322
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• 2015

This study was conducted to obtain basic data for deriving the appropriate application amount of insecticide for effective pest control. We have investigated the correlation among the application amount of insecticide, the adhesion amount of active ingredient and the pest control effect. The linear standard curve of acetamiprid was $R^2=0.9994$, and the scope of the recovery factor was between 71% and 93% with less than 6% of the coefficient of variation. During the test conducted in 2015, the application amount was reduced to 302 L/10a which was 70 L less than the previous year and the spraying pressure was reduced as well. After analyzing the adhesion amount of active ingredient, it was found that a correlation coefficient of adhesion amount of the active ingredients became lower from 82% to 69%, that indicated insecticide liquid was evenly distributed compared to 2014. Also more than 95% of control effect was displayed, thereby indicating that there is a close relation with the correlation coefficient of the adhesion amount of active ingredient. It also presented that the adhesion amount of active ingredient on the ground was 2.2 times more than that on the leaves of apple trees.

• Korean Journal of Food Science and Technology
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• v.50 no.4
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• pp.377-382
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• 2018

An HPLC method was developed to quantitate a marker, oxyresveratrol (ORT), for the standardization of mulberry branch extracts (MBE) as a functional ingredient. HPLC was performed on a $C_{18}$ column with a gradient elution using 0.05% $H_3PO_4$ and acetonitrile at a flow rate of 0.8 mL/min, and detected at 320 nm. The HPLC method was validated according to Korea Food and Drug Administration (KFDA) guideline of analytical procedures with respect to specificity, linearity, accuracy and precision. Calibration curve of ORT showed high linearity ($R^2=1$), and limits of detection and quantification were 0.3 and $1.0{\mu}g/mL$, respectively. Relative standard deviation values from intra-and inter-day precision were less than 3.52 and 4.70%, respectively. Recovery rate ranged from 97.64% to 103.69%, and ORT content in MBE was approximately 3.78%. These results suggest that the HPLC method developed for the analysis of ORT in MBE is simple, efficient, and could contribute to the quality control of MBE.

• Analytical Science and Technology
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• v.26 no.4
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• pp.221-227
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• 2013

A sensitive and selective liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed for the investigation of the ginsenoside Rg1 in human plasma. After addition of internal standard (digoxin), plasma was diluted with acetone and methanol (80:20), the supernatant was concentrated and analyzed by LC-MS/MS. The optimal chromatographic separation was achieved on an Agilent Eclipse XDB-C18 column ($4.6{\times}150mm$, $5{\mu}m$) with a mobile phase of 0.1% formic acid in water and 0.1% formic acid in methanol at a flow rate of 0.9 mL/min gradient mode. The standard calibration curve for ginsenoside Rg1 was linear ($r^2=0.9995$) over the concentration range 1~500 ng/mL in human plasma. The intra- and inter-day precision over the concentration range of ginsenoside Rg1 was lower than 7.53% (correlation of variance, CV), and accuracy exceeded 98.28%. This LC-MS/MS assay of ginsenoside Rg1 in human plasma is applicable for quantifying in the pharmacokinetic study.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.2
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• pp.244-248
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• 2013

We studied the development of schizandrin as a marker compound in Jangsu Omija. Schizandrin was validated for its LOD (limit of detection), LOQ (limit of quantitation), precision, accuracy, and recovery by HPLC relative to Omija powder. It showed a high linearity in the calibration curve with a coefficient of correlation ($R^2$) of 0.9990. The LOD and LOQ were 0.2 ${\mu}g/mL$ and 0.5 ${\mu}g/mL$, respectively. The intra- and inter-day precision of schizandrin calibration standards was 0.06~0.66% and 0.13~1.19%, respectively, and the intra- and inter-day accuracy of schizandrin was 98.35~103.30% and 98.35~103.00%, respectively. Overall, schizandrin was validated through our analytical methods as a marker compound in Jangsu Omija.

• YAKHAK HOEJI
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• v.57 no.4
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• pp.293-298
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• 2013

Hwangryunhaedok-tang (HRT) is a traditional herbal medicine, which has been known as a useful prescription for anti-biotic, anti-inflammatory, anti-oxidative and immunosuppressive activity. In this study, the variation in the amount of eight bioactive components of Hwangryunhaedok-tang (HRT) and its fermentation HRT with Lactobacillus casei KFRI 127, Lactobacillus curvatus KFRI 166 and Lactobacillus confuses KFRI 227 was investigated via high-performance liquid chromatography coupled with diode array detection (HPLC-DAD). Simultaneous qualitative and quantitative analysis of eight bioactive components; geniposide, genipin, baicalin, wogonoside, palmatine, berberine, baicalein and wogonin was achieved by comparing their retention times ($t_R$) and UV spectra with those of the standard components. All calibration curve of standard components showed good linearity ($r^2$ >0.979). As a result, the geniposide amount was $15.52{\pm}0.19{\mu}/mg$ that as a main components in HRT. The wogonoside was decreased by 29.28~58.35% with Lactobacillus casei KFRI 127 and L. confuses KFRI 227 ($3.17{\pm}0.31{\mu}g/mg$ and $3.55{\pm}0.13{\mu}g/mg$) compared with the original HRT ($5.02{\pm}0.14{\mu}g/mg$). Otherwise wogonin was increased by 16.28~41.86% with Lactobacillus casei KFRI 127 and L. confuses KFRI 227 ($0.61{\pm}0.01{\mu}g/mg$ and $0.50{\pm}0.02{\mu}g/mg$) compared with the original HRT($0.43{\pm}0.00{\mu}g/mg$). HRT fermented with L. casei KFRI 127 and L. confuses KFRI 227 were evaluated as creating the changes in wogonoside to that aglycon wogonine. In the fermented HRT using Lactobacillus acidophilus KFRI 166, the genipin was only detected, among 3 species of fermentation strains. Thus, these results considered that the strains 166 were exhibited the remarkable changes in genipin.

• Analytical Science and Technology
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• v.21 no.4
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• pp.316-325
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• 2008

An inductively coupled plasma mass spectrometry (ICP-MS) instrument equipped with flow injection-hydride generation system was used for the determination of trace arsenic in seawater sample. The accuracy in this method was verified by the analysis of certified reference materials (CRM) of seawater (CASS-4, NASS-5). The analytical results agreed with certified value within the range of uncertainty. The expanded uncertainties for CASS-4 and NASS-5 in this experiment were ranged from 6.2% to 6.8% obtained from repeated analyses of the CRMs (n=5). The detection limit of $As^+$ (m/z=74.9216) in this method was confirmed about 0.01 ug/kg. Linearity obtained from calibration curve of arsenic was excellent ($R^2=1$). The detection at $As^+$ (m/z=74.9216) and $AsO^+$ (m/z=90.9165) by using oxygen reaction gas in DRC mode was compared. Sensitivity at $AsO^+$ (m/z=90.9165) was decreased about 25-fold, but the analytical results are the same that at $As^+$ (m/z=74.9216).

• Tuberculosis and Respiratory Diseases
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• v.45 no.2
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• pp.341-350
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• 1998

Background: Airway hyperreponsiveness is a cardinal feature of asthma. It consists of both an increased sensitivity of the airways, as indicated by a smaller concentration of a constrictor agonist needed to initiate the brochoconstrictor response and an increased reactivity, increments in response induced subsequent doses of constrictor, as manifested by slopes of the dose-response curve. The purpose of this study is to observe the relationship between bronchial sensitivity and reactivity in asthmatic subjects. Method: Inhalation dose-response curves using methacholine were plotted in 56 asthmatic subjects. They were divided into three groups(mild, moderate and severe) according to clinical severity of bronchial asthma. PC20 were determined from the dose-response curve as the provocative concentration of the agonist causing a 20% fall in FEVl. PC40 were presumed or determined from the dose response curve, using the PC20 and the one more dose after PC20. Reactivity was calculated from the dose-response curve regression line, connecting PC20 with PC40. Results: PC20 were 1.83mg/ml in mild group, 0.96mg/ml in moderate, and 0.34mg/ml in severe. PC40 were 7.l7mg/ml in mild group, 2.34mg/ml in moderate, and 0.75mg/ml in severe. Reactivity were $24.7{\pm}17.06$ in mild group, $46.1{\pm}22.l0$ in moderate, and $59.0{\pm}5.82$ in severe. There was significant negative correlation between PC20 and reactivity (r= -0.70, P<0.01). Conclusion: Accordingly, there was significant negative correlation between bronchial sensitivity and brochial reactivity in asthmatic subjects. However, in some cases, there were wide variations in terms of the reactivity among the subjects who have similar sensitivity. So both should be assessed when the bronchial response tor bronchoconstrictor agonists is measured.