• 한국항해항만학회지
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• 제32권10호
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• pp.771-776
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• 2008

선박에서 제어판의 역할은 운동을 제어하는데 목적이 있으며 이는 곧 조종성능을 결정하는 중요한 요소이다. 본 연구에서는 플랩타의 성능평가를 위하여 $Re=3.0{\times}10^4$에서 영각에 대응하는 플랩각에 따른 속도 및 에너지 분포를 2-프레임 그레이레벨 상호상관 PIV기법을 이용하여 비교 분석하였다. 또한 영각 10도와 20도에서 전통적인 단동타의 유동특성과 비교하여 플랩타의 성능특성을 평가하였다. 영각 10도에서는 양력, 영각 20도에서는 항력에 의한 측압력을 향상시킬 수 있었다. 영각 10도에서 플랩조작만으로 박리점과 경계층영역의 변화가 가능하였다.

• 분석과학
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• 제34권5호
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• pp.212-224
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• 2021

The intent of the present work was to develop a simple, sensitive, accurate, precise, rapid and economical UV- spectrophotometric and reverse phase high pressure liquid chromatographic method for the simultaneous estimation of Spironolactone and Furosemide in bulk and combined tablet dosage forms. UV-Spectrophotometry was carried out by simultaneous equation method using 0.02 M potassium dihydrogen phosphate buffer pH 3.5: Acetonitrile (50:50) v/v as a solvent. The linearity range was 2-14 ㎍ mL^-1 for Spironolactone and Furosemide with a correlation coefficient > 0.99. The chromatographic separation was achieved on 250 mm × 4.6 mm, hypersil BDS C18 column with particle size 5 ㎛, by using an isocratic mixture of 0.02 M potassium dihydrogen phosphate buffer pH 3.5: Acetonitrile: tert butyl methyl ether (49:50:1) v/v/v as a solvent at a flow rate of 1 mL min^-1 and UV detection was carried out at 254 nm. The retention time were observed to be 3.666 and 6.661 minutes for Furosemide and Spironolactone respectively. The two developed methods were validated according to the ICH guidelines for accuracy, precision, linearity, LOD, LOQ and were found to be within the limits. It can be concluded that these two methods could be successfully used for the simultaneous estimation of Spironolactone and Furosemide in bulk and combined tablet dosage forms.

• Journal of Applied Biological Chemistry
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• 제62권2호
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• pp.129-135
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• 2019

Salvia miltiorrhiza Radix is cultivated in Korea and China and is traditionally used to treat cardiovascular diseases. In this study, we developed and validated a quantitative analysis method for S. miltiorrhiza Radix using high-performance liquid chromatography (HPLC). Identification was performed using ultra performance liquid chromatography-tandem mass spectrometry. For quantitative analysis, we used seven marker compounds. Separation conditions for HPLC were optimized using an ODS column with gradient conditions of 1% formic acid in distilled water and 1% formic acid in acetonitrile, with a flow rate of 0.8 mL/min and a detection wavelength of 280 nm. This method showed good linearity ($R^2=0.9998$), precision (relative standard deviation ${\leq}3.3%$), accuracy (recovery of 94.16-102.89%), limit of detection ($7.53{\mu}g/mL$), and limit of quantification ($23.71{\mu}g/mL$). This approach successfully quantified marker compounds in S. miltiorrhiza Radix. The individual marker compounds were identified by comparing the molecular masses and retention times with does standard compounds. Marker compound contents of S. miltiorrhiza Radix were investigated with different cultivation regions. Seven marker compounds were detected and quantified in all samples. Among them, salvianolic acid B showed the highest contents and it ranged from 4.13 to 7.15%. The salvianolic acid B content (7.15%) of marker compound was the highest in Bonghwa, and the tanshinone IIA content (1.90%) was the highest in Pohang. The results of marker compounds and developed method were intended to provide a favorable reference for the study of S. miltiorrhiza Radix from different regions of Korea.

• 분석과학
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• 제32권3호
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• pp.96-104
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• 2019

Agastache rugosa, known as Korean mint, is a medicinal plant with many beneficial health effects. In this study, a simple and reliable HPLC-UV method was proposed for the quantification of rosmarinic acid (RA) in the aqueous extracts of A. rugosa. RA was selected as a quantification marker due to its easiness in procurement and analysis. The developed method involved chromatographic separation on a $C_{18}$ column ($250{\times}4.6mm$, $5{\mu}m$) at room temperature. The mobile phase consisted of water and acetonitrile both containing 2 % acetic acid and was run at a flow rate of $1mL\;min^{-1}$. The method was validated for specificity, linearity, precision, and accuracy. It was specific to RA and linear in the range of $50-300{\mu}g\;mL^{-1}$ ($r^2=0.9994$). Intra-day, inter-day, and inter-analyst precisions were ${\leq}0.91%\;RSD$, ${\leq}1.40%\;RSD$, and 1.94 % RSD, respectively. Accuracy was 93.3-95.9 % (${\leq}1.21%\;RSD$). The method could be applied to three batches of bulk samples and three batches of lab scale samples, which were found to be $0.64({\pm}0.04)mg\;g^{-1}$ and $0.48({\pm}0.02)mg\;g^{-1}$ for the dried raw materials of A. rugosa. The results show that the proposed method can be used as a readily applicable method for QC of health functional foods containing the aqueous extracts of A. rugosa.

• 한국축산식품학회지
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• 제39권1호
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• pp.23-34
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• 2019

Fat reduction in the formulation of cheese emulsion causes problems in its flowability and functional characteristics during spray-dried cheese powder production. In order to eliminate these problems, the potential of using microparticulated whey protein (MWP) in cheese emulsions was examined in this study. Reduced-fat white-brined cheese emulsions (RF) with different dry-matters (DM) (15%, 20%, and 25% excluding emulsifying salt) were produced using various MWP concentrations (0%-20% based on cheese DM of emulsion). Their key characteristics were compared to full-fat cheese emulsion (FF). MWP addition had no influence on prevention of the phase separation observed in the instable group (RF 15). The most notable effect of using MWP was a reduction in apparent viscosity of RF which significantly increased by fat reduction. Moreover, increasing the amount of MWP led to a decrease in the values of consistency index and an increase in the values of flow behavior index. On the other hand, using high amounts of MWP made the emulsion more liquid-like compared to full-fat counterpart. MWP utilization also resulted in similar lightness and yellowness parameters in RF as their full-fat counterparts. MWP in RF increased glossiness and flowability scores, while decreased mouth coating scores in sensory analyses. Fat reduction caused a more compact network, while a porous structure similar to FF was observed with MWP addition to RF. In conclusion, MWP showed a good potential for formulation of reduced-fat cheese emulsions with rheological and sensorial characteristics suitable to be used as the feeding liquid in the spray drying process.

• Journal of Biomedical and Translational Research
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• 제19권4호
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• pp.130-139
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• 2018

This study aimed to analyze a high-performance liquid chromatography (HPLC) separation using a pentafluorophenyl column of parent drug hydroxychloroquine (HCQ) and its active metabolite, desethylhydroxchloroquine (DHCQ) applying to determine bioequivalence of two different formulations administered to patients. A rapid, simple, sensitive and specific liquid chromatography-tandem mass spectrometry (LC-MS/MS) method has been developed and validated for bioanalysis of HCQ and its metabolite DHCQ in human whole blood using deuterium derivative $hydroxychloroquine-D_4$ as an internal standard (IS). A triple-quadrupole mass spectrometer was operated using electrospray ionization in multiple reaction monitoring (MRM) mode. Sample preparation involves a two-step precipitation of protein techniques. The removed protein blood samples were chromatographed on a pentafluorophenyl (PFP) column ($50mm{\times}4.6mm$, $2.6{\mu}m$) with a mobile phase (ammonium formate solution containing dilute formic acid) in an isocratic mode at a flow rate of 0.45 mL/min. The standard curves were found to be linear in the range of 2 - 500 ng/mL for HCQ; 2 - 2,000 ng/mL for DHCQ in spite of lacking a highly sensitive MS spectrometry system. Results of intra- and inter-day precision and accuracy were within acceptable limits. A run time of 2.2 min for HCQ and 2.03 min for DHCQ in blood sample facilitated the analysis of more than 300 human whole blood samples per day. Taken together, we concluded that the assay developed herein represents a highly qualified technology for the quantification of HCQ in human whole blood for a parallel design bioequivalence study in a healthy male.

• 분석과학
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• 제32권4호
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• pp.139-146
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• 2019

A simple and reliable analytical method based on high-performance liquid chromatography-ultraviolet detection was established for the analysis of the flowers of Chrysanthemum morifolium (CM). Luteolin-7-O-glucoside (LU7G) was chosen as a target analyte considering its content, availability, and ease of analysis. Chromatographic separation of LU7G was achieved using a Phenomenex Gemini $C_{18}$ column ($250{\times}4.6mm$, $5{\mu}m$) run with a mobile phase consisting of 0.5 % acetic acid in water and 0.5 % acetic acid in acetonitrile at a flow rate of $1.0mL\;min^{-1}$. The detection wavelength and column temperature were set at 350 nm and $40^{\circ}C$, respectively. Method validation was performed according to the AOAC guidelines and the method was specific, linear ($R^2=0.9991$ for $50-300{\mu}g\;mL^{-1}$), precise (${\leq}3.91%$RSD), and accurate (100.1-105.7 %). The limits of detection and quantification were 3.62 and $10.96{\mu}g\;mL^{-1}$, respectively. The established method was successfully applied to determine the contents of LU7G in various batches of bulk CM extracts and labscale CM extract. The developed method is a readily applicable method for the quality assessment of CM and its related products.

• Mass Spectrometry Letters
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• 제10권1호
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• pp.18-26
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• 2019

We developed a bioanalytical method for simultaneous determination of nine NBOMe derivatives (25H-NBOMe, 25B-NBOMe, 25E-NBOMe, 25N-NBOMe, 25C-NBOH, 25I-NBOH, 25B-NBF, 25C-NBF, and 25I-NBF) in human plasma using liquid chromatography tandem mass spectrometry (LC-MS/MS). Human plasma samples were pre-treated using solid-phase extraction. Separation was achieved on a C18 column under gradient elution using a mobile phase containing 0.1% formic acid in acetonitrile and 0.1% formic acid in water at a flow rate of 0.3 mL/min. Mass detection was performed in the positive ion mode using multiple reaction monitoring. The calibration range was 1-100 ng/mL for all quantitative analytes, with a correlation coefficient greater than 0.99. The intra- and inter-day precision and accuracy varied from 0.85 to 6.92% and from 90.19 to 108.69%, respectively. The recovery ranged from 86.36 to 118.52%, and the matrix effects ranged from 27.09 to 99.72%. The stability was acceptable in various conditions. The LC-MS/MS method was validated for linearity, accuracy, precision, matrix effects, recovery and stability in accordance with the FDA guidance. The proposed method is suitable for reliable and robust routine screening and analysis of nine NBOMe derivatives in forensic field.

• 한국동물위생학회지
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• 제43권4호
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• pp.261-265
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• 2020

Each commercial cyromazine insecticide has different HPLC conditions. The aim of this study was to establish a standardized chromatographic method for the determination of cyromazine in commercial insecticides. The separation was achieved on two C18 columns - Waters® Bondapak C (4×300 nm i.d., 10 ㎛) and X bridge (4.6×250 nm i.d., 5 ㎛) using a mobile phase composed of water/methanol/ethanolamine (76:24:0.1, v/v), with UV detection at wavelengths 230 nm and 254 nm. A total of six commercial cyromazine insecticides were analyzed. In this study, the optimal high-performance liquid chromatography conditions for the analysis of cyromazine were as follows: a mobile phase of water/methanol/ethanolamine (76:24:0.1, v/v) at a flow rate of 1.0 mL/min and a detection wavelength of 230 nm using a X bridge C18 column (4.6×250 nm i.d., 5 ㎛) at a column temperature of 25℃. The calibration curve was linear in the concentration range of 5~50 ㎍/mL, with a correlation coefficient of 0.99995. The cyromazine detection limit was 0.2 ㎍/mL, and the limit of quantification was 0.59 ㎍/mL. The percentage recovery ranged from 99.8% to 101.0% for cyromazine, and the relative standard deviation was not over 2.0%. The cyromazine concentration ranged from 92.7% to 109.4% and was within the acceptable range (90~120%) for the percent of the labeled amount. This method was found to be suitable for determining cyromazine in commercial insecticides.

• 한국해안·해양공학회논문집
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• 제32권6호
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• pp.420-433
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• 2020

기존 케이슨방파제의 안정성을 높이기 위해 케이슨 전면 또는 후면에 추가로 신규 케이슨을 설치하여 보강하는 경우 박리에 의한 에너지 손실효과와 케이슨과 케이슨 사이의 공극률 변화에 따른 개별 원형케이슨에 작용하는 파력 및 파처오름 특성 평가는 중요하다. 본 연구에서는 고유함수전개법에 투과성판에서의 속도는 판 전후의 압력차에 선형적으로 비례한다는 Darcy의 법칙을 이용하여 원형케이슨들간의 공극률 계수 변화에 따른 2열 배치된 원형방파제에 작용하는 파랑 특성을 분석하였다. 수치해석의 신뢰성을 확보하기 위해 Sankarbabu et al.(2008)의 수치 해석결과와 비교를 수행하였으며, 다양한 변수에 따른 개별 이중 원형케이슨에 작용하는 파력 및 파처오름 특성을 나타내었다.