• Analytical Science and Technology
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• v.20 no.5
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• pp.400-405
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• 2007

The comparative analysis of glycerin in cosmetic samples was carried out by LC/MS and $^1H$ NMR spectrometry. For the LC/MS analysis, aqueous solution was controlled in strong basic condition with sodium hydroxide, and benzoyl chloride was added to the solution for the derivatization of glycerin. The derivative was extracted using pentane and analyzed by the LC/MS. For the $^1H$ NMR analysis, sample was directly dissolved in $D_2O$ solvent without pretreatment. The quantitative analysis of glycerin was done by $^1H$ NMR ERETIC method. The analysis results of LC/MS and $^1H$ NMR showed that the calibration curves were a good linearity with $r^2=0.9991$ in the range of 0.1 to $10{\mu}g/mL$ and $r^2=1$ in the range of 25 to $500{\mu}g/mL$, respectively.

• Korean Journal of Clinical Laboratory Science
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• v.37 no.1
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• pp.22-26
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• 2005

Total homocysteine is now considered a risk factor for cardiovascular diseases. I increased interest has led to a multitude of studies requiring the determination of total homocysteine in conjunction with other factor. There are various methods for measuring total homocysteine, including HPLC, FPIA, GC-MS and LC-MS/MS. The most recent method for measuring total homocysteine uses a deuterium-labelled internal standard and tandem mass spectrometry. This development requires no derivatization and therefore leads to an increase in sample throughput compared to other techniques. We have evaluated the method for homocysteine by the LC-MS/MS method, and the correlation between the FPIA method and the LC-MS/MS method. The standard curve (0, 5, 10, 20, 50, 100 uM) was linear over the range examined (up to 100 uM). The lower limit of quantification (CV < 10 %) was 0.5 uM/L and the lower limit of detection (S/N >3) was 0.1 uM/L. Intra-assay variation and inter-assay variation were both <6 %. The comparision study for homocysteine concentration showed good correlation (r=0.9684) between the FPIA method and LC-MS/MS methods. Our conclusion is that the method showed relatively good precision, and was rapid and accurate.

• Journal of Environmental Health Sciences
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• v.36 no.1
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• pp.52-60
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• 2010

High performance liquid chromatography (HPLC) and liquid chromatography mass spectrometry (LC/MS) have been widely used to quantify aflatoxins in food, but these methods are expensive, time-consuming, unsuitable for analysis of the routine screening of large sample numbers and require derivatization and high level techniques to perform. The objective of this study is to detect aflatoxins in a large number of foods by a high efficient analytical system of combined enzyme linked immunosorbent assay (ELISA) for screening and LC/MS/MS for confirmation. The samples spiked individually with aflatoxin $B_1$ (0.5 and 1.0 ng/g) and total aflatoxins (10 ng/g) were analyzed by ELISA and LC/MS/ MS, and the recoveries for ELISA and LC/MS/MS were 71.8~119.2% and 70.8~135.3%, respectively. A total of 378 samples (grains, nuts, soybean and fermented soybean foods, pepper and fermented pepper foods) were purchased from the six major cities in Korea and analyzed by ELISA-LC/MS/MS system. Twenty two (5.8%; peanut: 11, pistachio: 2, walnut: 6, almond: 1, pepper powder: 1, pepper paste: 1) out of 378 samples were screened as aflatoxin B1 positive by ELISA, but, 4 (1.1%; peanut: 2, pistachio:1, pepper powder: 1) out of the 22 samples screened were confirmed as aflatoxins positive at levels of 1.02~52.79 ng/g by LC/MS/MS. ELISA-LC/MS/MS system provides a more rapid, accurate and cost-effective method for the detection of aflatoxins in large number of samples.

• Analytical Science and Technology
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• v.25 no.6
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• pp.435-440
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• 2012

A liquid chromatography-electrospray ionization-tandem mass spectrometry method (LC-ESI-MS/MS) was used for determining perchlorate in the Gum-River surface water. Sample was directly injected into LC-ESI-MS/MS after the filtrations using PTFE filter paper. The coefficient of variation of perchlorate was less than 3% and the limit of quantification was 0.17 ${\mu}g/L$. Water samples were collected from thirty-five basins of Gum-River on February, April and June 2012, respectively. As a result, perchlorate was detected in the concentration range of 0.23-3.73 ${\mu}g/L$ (mean 0.20 ${\mu}g/L$) in the frequency of 15% in general surface water and in the concentration range of 0.36-25.10 ${\mu}g/L$ (mean 1.69 ${\mu}g/L$) in the frequency of 36% in surface water samples near industry area.

• Korean Journal of Food Science and Technology
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• v.46 no.5
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• pp.549-555
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• 2014

The geographical origin of commercial red ginseng concentrate was studied using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The ginsenoside content of domestic and Chinese red ginseng concentrates was determined. Four types of suspected origin samples could be selected this technique. The LC-MS/MS data were statistically analyzed on the basis of canonical function analysis and principal component analysis. Domestic and Chinese samples could be discriminated via canonical function analysis using posterior probability. In addition, the mixture ratio (Korean or Chinese origin) of the unknown origin specimen could be predicted based on the relationship between the mixing concentration of red ginseng concentrates and principal component 1.

• KOGO NEWS
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• v.5 no.4
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• pp.4-5
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• 2005

• YAKHAK HOEJI
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• v.57 no.4
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• pp.250-257
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• 2013

Biosimilars are important drugs in medicine and contain many glycosylated proteins. Thorough analysis of the glycosylated protein is a prerequisite for evaluation of biosimilar glycan drugs. A method to assess the diversity of N-glycosylation sites and N-glycans from biosimilar glycan drugs has been developed using two separate methods, LC-MS/MS and MALDI-TOF MS, respectively. Development of sensitive, accurate, and efficient methods for evaluation of glycoproteins is still needed. In this study, analysis of both N-glycosylation sites and N-glycans of glycoprotein was performed using the same LC-MS/MS with two different nano-LC columns, nano-C18 and nano-porous graphitized carbon (nano-PGC) columns. N-glycosylated proteins, including RNAse B (one N-glycosylation site), Fetuin (three sites), and ${\alpha}$-1 acid glycoprotein (four sites), were used, and small amounts of each protein were used for identification of N-glycosylation sites. In addition, high mannose N-glycans (one type of typical glycan structure), Mannose 5 and 9, eluted from RNAse B, were successfully identified using nano-PGC-LC MS/MS analysis, and the abundance of each glycan from the glycoprotein was calculated. This study demonstrated an accurate and efficient method for determination of N-glycosylation sites and N-glycans of glycoproteins based on high sensitive LC-MS/MS using two different nano-columns; this method could be applied for evaluation of the quality of various biosimilar drugs containing N-glycosylation groups.

• Korean Journal of Pharmacognosy
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• v.44 no.4
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• pp.350-361
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• 2013

Asarum sieboldii has been used for treatment of fever, pain, common cold, and chronic sinusitis in Korea. In this study, we performed quantification analysis of seven major constituents including aristolochic acid I, aristolochic acid II, ${\alpha}$-asarone, ${\beta}$-asarone, elemicin, methyl eugenol, and safrole in the 70% ethanol extract of Asarum sieboldii and its solvent fractions, n-hexane, ethylacetate, n-butanol, and water ones using a ultra-performance liquid chromatography-electrospray ionization-mass spectrometer(UPLC-ESI-MS) and gas chromatography-mass spectrometer(GC-MS). Regression equations of seven components were acquired with $r^2$ values >0.99. The values of limit of detection(LOD) and quantification(LOQ) were 0.1-3.9 ng/mL and 0.3-11.7 mg/mL, respectively. The amount of the seven compounds in Asarum sieboldii were not detected -143.66 mg/g. The established LC-MS/MS and GC-MS methods will be helpful to improve quality control of Asarum sieboldii.

• YAKHAK HOEJI
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• v.56 no.3
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• pp.158-163
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• 2012

Lidocaine has been studied for many chronic pain conditions, including postherpetic neuralgia (PHN) and recently it has also been increasingly used in transdermal drug delivery systems. In this study, pharmacokinetics of a lidocaine patch was studied in four hairless male rats. The plasma concentration was determined by a validated LC/MS/MS method after applying a $3{\times}2cm^2$ (30mg) patch for 12 hours. From the plasma lidocaine concentration vs time curves, $AUC_{0-20h}$, Cmax, and Tmax of lidocaine patch were $2,926.32{\pm}335.28ng{\cdot}h/ml$, $256.86{\pm}29.63ng/ml$, and $6.00{\pm}2.31h$, respectively.

• Analytical Science and Technology
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• v.36 no.1
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• pp.12-21
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• 2023

Protein glycation is vital to aging and disease. However, glycated proteins are low-abundant in plasma, rendering them difficult to identify using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Many studies have analyzed glycated peptides with high reproducibility. Here, glycated peptides in human serum were analyzed by LC-MS/MS using data-dependent acquisition (DDA) and parallel reaction monitoring (PRM). Boronic acid (BA) enrichment of in vitro glycated human serum peptides was performed. BA enrichment identified the most glycated peptides, and the glycated peptides of the more diversified proteins, excluding albumin, were analyzed. In PRM, glycated albumin PSMs were the most common, and this method exhibited the best reproducibility. The results of this study could help compare methods for identifying glycation-related biomarkers.