• Analytical Science and Technology
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• v.5 no.4
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• pp.465-469
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• 1992

An analytical procedure is presented for the quantitative determination of lactose, glucose, and galactose in the hydrolyzate of lactose by ${\beta}$-galactosidase with high-performance liquid chromatography. An Aminex HPX-87C column at $85^{\circ}C$ and refractive index detector were used to resolve lactose, glucose, and galactose in only 12 minutes with distilled and deionized water as a mobile phase. The validity of high-performance liquid chromatography as a method for the assay of ${\beta}$-galactosidase was supported by recovery experiments and comparision of results with those by ONPG method, a spectrophotometric assay. The procedure was appropriate for determination of sugars in the enzyme reaction mixture and could by applied to analysis of ${\beta}$-galactosidase activity.

• Analytical Science and Technology
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• v.15 no.5
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• pp.410-416
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• 2002

In this study, a new quantitative analytical method has been developed for the rapid determination of vancomycin in human plasma and urine using liquid chromatography/tandem mass spectrometry (LC - MS/MS). Chromatography was carried out on a $C_{18}$ XTerra MS column ($2.1{\times}30mm$) with a particle size of $3.5{\mu}m$. The mobile phase was 0.25% formic acid in 10% acetonitrile and the flow rate was $250{\mu}L/min$. Vancomycin and caffeine (internal standard) were detected by MS/MS using multiple reaction monitoring (MRM). Vancomycin gives a predominant doubly protonated precursor molecule ($[M+2H]^{2+}$) at m/z 725.0 and a corresponding product ion of m/z 100.0. Detection of vancomycin was good, accurate and precise, with a limit of detection of 1 nM in plasma. The calibration curves for vancomycin in human plasma was linear in a concentration range of $0.01{\mu}M$ - $100{\mu}M$ for plasma. This method has been successfully applied to determine the concentration of vancomycin in human plasma and urine from pharmacokinetic study and relative studies.

• Proceedings of the IEEK Conference
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• 2002.06a
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• pp.319-322
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• 2002

In this paper, we consider a generalized rule of retransmission request, identified as (Μ, $\sigma$) rule for multicopy transmission ARQ. Following a revised rule to conform with a strict criterion for requesting a retransmission, we can reduce the probability that a packet accepted by the receiving node is still being infected with errors. In turn, such amendment invokes a degradation of delay and throughput performance. For a quantitative evaluation of (Μ, $\sigma$) rule, we develop an analytical method to calculate probability of error remains, maximum throughput, average and peak delays, and delay variation. From the numerical examples made by use of the analytical method, we observe a performance trade-off between probability of error remains and delay/throughput. We also confirm the adaptability of (Μ, $\sigma$) rule to meet various QoS requirements.

• YAKHAK HOEJI
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• v.41 no.5
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• pp.539-546
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• 1997

Capillary electrophoresis (CE) is perceived as an attractive tool for the analysis of pharmaceuticals and biological materials because of their high separation efficiency, easy separation and low running cost. New concept of micellar electrokinetic capillary chromatography (MECC) expanded the application of CE to the separation of neutral molecules. Validation of CE as an analytical technique for quality control of pharmaceuticals should be confirmed by quantitative analysis and the peak confirmation. In this study, the quantitative analyses of various types of neutral, acidic and basic components (acetaminophen, caffeine, ascorbic acid, riboflavin, thiamine, chlorpheniramine, phenylpropanolamine, dl-methylephedrine and dextromethorphan) in complex cold medicines have been accomplished using CE. Combined methods of MECC using SDS and capillary zone electrophoresis lowering the pH of running buffer were adopted to determine the ingredients in capsule type or liquid formula complex medicines without particular sample pretreatment. The results indicate that CE is a promising technique for quality control analysis of pharmaceuticals as a validation method.

• Journal of Korean Society of Water and Wastewater
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• v.27 no.6
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• pp.827-836
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• 2013

Due to the stringent drinking water quality, formaldehyde will be included in Korean drinking water standard from year 2014. However, its standard analytical method has not yet been established. This study compares two analytical methods, DNPH-LC and ACFAS with respect to their analysis principles, Method Detection Limit (MDL), Limit Of Quantitation(LOQ), precision, accuracy, reproducibility, convenience, number of samples analyzed per hour and analysis cost. These methods measure absorption intensity at 360 nm by using HPLC after DNPH-derivatization (DNPH-LC) and at 410 nm by using Automated Continuous Flow Absorption Spectrophotometer (ACFAS), respectively. Reproducibility was tested by repeating the analysis 7 times using a standard solution for each method. For DNPH-LC method, MDL was $0.5{\mu}g/L$, LOQ was $1.58{\mu}g/L$ with standard deviation of $0.16{\mu}g/L$. For ACFAS method, they were $0.27{\mu}g/L$, $0.85{\mu}g/L$L with standard deviation of $0.09{\mu}g/L$, respectively. Both methods satisfied the requirement set by the Korean drinking water quality standard. Complexity of sample pretreatment procedure for DNPH-LC method may cause large error and, consequently, the analytical result will depend on the level of skill of analyst. In contrast, ACFAS method which used only one reagent equipped with an automated injection device showed little analytical error. It costs about $5.00 and $1.00 for one sample to analyze by the DNPH-LC method and the ACFAS method, respectively. Compared to the DNPH-LC method, ACFAS method provided more reliable analytical results. In terms of convenience, easiness and analytical cost, ACFAS method was demonstrated to be superior to the DNPH-LC method. The results of this study suggested that the ACFAS method could be adapted as a proper method for determining formaldehyde content in drinking water.

• Analytical Science and Technology
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• v.33 no.5
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• pp.224-231
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• 2020

With the improvement in the standard of living and extension of life expectancy, the incidence of prostate diseases has increased yearly, thus becoming a serious disease affecting the health of men. The extract mixture of Cornus officinalis and Stauntonia hexaphylla leaves is a developed functional food formula to improve prostate health. This study developed a simultaneous analytical method of bioactive compounds for quantifying the mixture of Cornus officinalis and S. hexaphylla leaves using high-pressure liquid chromatography-ultraviolet (HPLC-UV). HPLC analytical condition was performed on a Hector C₁₈ column with a mobile phase of 0.1 % formic acid in water (A) and 0.1 % formic acid in acetonitrile (B) under the following gradient conditions: 0-50 min, 12 %-40 % (B) at a flow rate of 1.0 mL/min. Meanwhile, this method was validated properly and successfully used to quantify the bioactive components of morroniside and hederacoside D in 20 sample batches and assess the quality of different ages and seasons of S. hexaphylla leaves. The result showed that the content of morroniside in the extract mixture of Cornus officinalis and S. hexaphylla leaves ranged from 1.38-1.62 mg/g, and the hederacoside D ranged from 28.42-32.02 mg/g, suggesting that this novel analytical method will be suitable for the quality control of the extract mixture to improve benign prostatic hyperplasia.

• Analytical Science and Technology
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• v.30 no.3
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• pp.130-137
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• 2017

The leaves (Mori Folium; MF), branches (Mori Ramulus; MR), and root bark (Mori Cortex Radicis; MCR) of the mulberry tree have been used as therapeutic herbs for centuries. Existing analytical methods were developed specifically for different parts of the tree and cannot be applied to samples containing a mixture of tree parts. Such method specialization is time-consuming and requires separate identification and quality control of each tree part. This report describes an HPLC method for the simultaneous quality control and discrimination of MF, MR, and MCR using four marker compounds: rutin, kuwanon G, oxyresveratrol, and morusin. An Optimapak $C_{18}$ column ($4.6{\times}250mm$, $5{\mu}m$) was used with a gradient elution of 0.1 % formic acid in water and acetonitrile. The flow rate was 1.0 mL/min and the detection wavelength was 270 nm. In quantitative analyses of the three parts, rutin (0.11 % w/w) was detected only in MF. The oxyresveratrol content (0.12 % w/w) was highest in MR. Kuwanon G (0.33 % w/w) and morusin (0.18 % w/w) were higher in MCR than in other parts. The HPLC method given herein can be used to simultaneously classify and quantify three herbal medicines from the mulberry tree.

• Journal of Korean Society on Water Environment
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• v.32 no.6
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• pp.670-699
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• 2016

In this study, 16 antibiotics were selected from among the top 30 veterinary antibiotics sold in South Korea in 2014, as well as from among the pharmaceuticals targeted by EPA method 1694, in order to review analytical methods for the detection of trace levels of antibiotics in environmental samples: surface water, soils, animal origin foods, and manures. LC-MS/MS was heavily used. In the chromatography for the detection of the selected antibiotics, the $C_{18}$ column was mostly used at the temperature of $30{\sim}40^{\circ}C$. Water and methanol/acetonitrile were commonly chosen as a nonpolar and a polar mobile phase, respectively. Gradient elution was applied to separate multiclass antibiotics. Volatile additives, such as formic acid, acetic acid, and ammonium acetate were mixed with the mobile phase to improve the ionization efficiency of analytes and the sensitivity in MS detection. Electrospray ionization (ESI) was widely used in the LC-MS/MS and positive ionization was preferred to determine the selected antibiotics. A protonated $[M+H]^+$ molecule was selected as a precursor ion, and its two transitions were analyzed, one for quantitative measurement and the other for confirmation. This study reviewed linearity of the calibration curve, recovery, repeatability, method detection limits (MDLs), and method quantification limits (MQLs) for each target compound used to validate the developed analytical methods.

• Mass Spectrometry Letters
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• v.5 no.3
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• pp.63-69
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• 2014

In this study, we present a new isotope-coded carbamidomethylation (iCCM)-based quantitative proteomics, as a complementary strategy for conventional isotope labeling strategies, with providing the simplicity, ease of use, and robustness. In iCCM-based quantification, two proteome samples can be separately isotope-labeled by means of covalently reaction of all cysteinyl residues in proteins with iodoacetamide (IAA) and its isotope (IAA-$^{13}C_2$, $D_2$), denoted as CM and iCCM, respectively, leading to a mass shift of all cysteinyl residues to be + 4 Da. To evaluate iCCM-based isotope labeling in proteomic quantification, 6 protein standards (i.e., bovine serum albumin, serotransferrin, lysozyme, beta-lactoglobulin, beta-galactosidase, and alpha-lactalbumin) isotopically labeled with IAA and its isotope, mixed equally, and followed by proteolytic digestion. The resulting CM-/iCCM-labeled peptide mixtures were analyzed using a nLC-ESI-FT orbitrap-MS/MS. From our experimental results, we found that the efficiency of iCCM-based quantification is more superior to that of mTRAQ, as a conventional nonisobaric labeling method, in which both of a number of identified peptides from 6 protein standards and the less quantitative variations in the relative abundance ratios of heavy-/light-labeled corresponding peptide pairs. Finally, we applied the developed iCCM-based quantitative method to lung cancer serum proteome in order to evaluate the potential in biomarker discovery study.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.19 no.1
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• pp.1-7
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• 2009

To establish the Fourier-Transform Infra-Red spectrophotometry(FTIR) Direct-On-Filter(DOF) technique as a useful analytical method for quartz in respirable dust samples, an influence of the kaolinite should be corrected. Respirable dust, created in a dust chamber containing the standard material of quartz and kaolinite were collected using a cyclone equipped with a 25 mm, $0.8\;{\mu}m$ pore size DM filter as a collection medium. This study was designed to compare three methods of correction for kaolinite when quantifying the content of quartz, including the least square, the optimum choice and the spectral subtraction methods. The content of quartz in the respirable dust samples was overestimated by 6.2% when mixed with kaolinite(35.5% by weight). The content of quartz containing kaolinite(72.8% by weight) were overestimated by 32%. The spectral subtraction method underestimated the quartz content by 1.5%, while the other two correction methods, the optimum choice and the least square method, overestimated the quartz content by 1.9% to 6.4% and 0.04 to 1.1%, respectively. The results of this study are suggested that, when correcting for effects of kaolinite on quantitative analysis of quartz in respirable dust by FTIR direct-on-filter method, the least square method produce the most unbiased results be compared with those of other correction methods.