• Analytical Science and Technology
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• v.28 no.5
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• pp.317-322
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• 2015

Simultaneous analytical method has developed for the determination of anion biocides in soil by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Chlorite and chlorate in soil were extracted with pure water, and cyanuric acid and sodium dodecylbenzenesulfonate (Na-DBS) were extracted with mobile phase (0.25 mM ammonium formate in 20 mM formic acid : acetonitrile (1:1)). The extract was injected into the LC-MS/MS system after filtration. The method detection limits in this study were 0.04 mg/kg for chlorite, 0.04 mg/kg for chlorate, 0.27 mg/kg for cyanuric acid, and 0.05 mg/kg for Na-DBS, respectively. The method was applied to the analysis of 50 soil samples collected from 40 sites sprayed with biocides and 10 background sites. As a result, anion biocides were not detected in all sites.

• 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.

• 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.

• Analytical Science and Technology
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• v.24 no.4
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• pp.237-242
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• 2011

In this study, an analytical method was developed for residual metamizol in beef and pork using LC/MS/MS. 4-methylaminoantipyrin (MAA), the main metabolite of metamizol was targeted for analysis instead of its parent compound. MAA was simply extracted from meat by acetonitrile, purified and then analyzed by multiple reaction monitoring method (MRM). Standard addition method was used for calibration. The calibration curves showed the linearity of $r^2$ > 0.99 for both matrices included. The developed method was validated by six-time intra-lab tests and inter-lab tests with two other institutes. The validation of the whole procedure for beef showed the intra-lab accuracies of 78-102% (CV 5.5-9.1%) and the inter-lab accuracy of 98% (CV 14%); the intra-lab accuracies of 95-99% (CV 3.9-5.6%) and the inter-lab accuracy of 111% (CV 13%).

• Korean Journal of Fisheries and Aquatic Sciences
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• v.54 no.4
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• pp.404-410
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• 2021

Although, mouse bioassay for the monitoring of azaspiracids (AZAs) toxins in shellfish has been used previously, the reported method has low sensitivity and it is time-consuming. Recently, there is an interest in the quantitative analysis of AZAs using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The purpose of this study is to verify the simultaneous analysis of AZAs in shellfish and tunicate in Korea using LC-MS/MS. To validate the method, linearity, limit of detection (LOD), limit of quantification (LOQ), precision, accuracy, and repeatability were determined. All standard compounds were analyzed within 7 min. The correlation coefficients (R²) of the standard solution was higher than 0.9995 (within the range of 0.8-10.0 ㎍/L). The LODs and LOQs of AZAs in shellfish were 0.08-0.16 ㎍/kg and 0.23-0.50 ㎍/kg, respectively. The accuracy and precision of the method for determining AZAs in shellfish were 87.1-93.0% and 1.23-4.91%, respectively. Consequently, the verified LC-MS/MS method is suitable to analyze AZAs in shellfish and tunicates in Korea.

• Analytical Science and Technology
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• v.30 no.2
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• pp.102-111
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• 2017

Here we reported a methodology for identification of triacylglycerols (TAGs) and diacylglycerols (DAGs) in coix seed by preparative thin layer chromatography (prep-TLC) and non-aqueous reversed-phase liquid chromatography (NARP LC)-atmospheric pressure chemical ionization (APCI) tandem mass spectrometry (MS/MS). Lipid components were extracted from coix seed by reflux extraction using n-hexane for 3 hr. TAGs and DAGs in coix seed extract were effectively purified and isolated from matrix interferences by prep-TLC and then analyzed by LC-APCI-MS and MS/MS for identification. TAGs were effectively identified taking into consideration of their LC retention behavior, APCI-MS spectra patterns, and MS/MS spectra of $[DAG]^+$ ions. In MS/MS spectra of TAGs, diacylglycerol-like fragment $[DAG]^+$ ions were useful to identify TAGs with isobaric fragment ions. Based on an established method, 27 TAGs and 8 DAGs were identified in coix seed extract. Among them, 15 TAGs and 8 DAGs were for the first time observed in coix seed. Interestingly, some of TAGs isolated by prep-TLC were partly converted into DAGs through probably photolysis process during storing in room temperature. Thus, degradation phenomenon of TAGs should be considered in the quality evaluation and nutritional property of coix seed. LC-APCI-MS/MS combined with prep-TLC will be practical method for precise TAG and DAG analysis of other herbal plants.

• Analytical Science and Technology
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• v.20 no.3
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• pp.198-203
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• 2007

The analysis method of 3-Monochloropropane-1,2-diol (3-MCPD) compound in water was developed using liquid chromatography with mass spectrometric detection. Aqueous solution was controlled in strong basic condition with sodium hydroxide, and then $25{\mu}L$ of benzoyl chloride was added to the solution for the derivatization of 3-MCPD. The derivative was extracted using pentane and analyzed by the selected ion monitoring (SIM) method of LC-MS. The results of analyses showed that the calibration curves was in the range of 1.0 to $100{\mu}g/mL$ with a good linearity (correlation coefficient of $r^2=0.992$) and limit of detection was below $0.01{\mu}g/mL$. The recoveries of this analysis method by LC-MS were 92.3-98.0 %.

• Korean Journal of Pharmacognosy
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• v.50 no.1
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• pp.65-71
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• 2019

One of the oriental medicine prescriptions, Sagunja-tang consists of four herbal medicines (Ginseng Radix, Poria Sclerotium, Atractylodis Rhizoma Alba, and Glycyrrhiziae Radix et Rhizoma) and has been used as a medicine to enhance tonify the function of spleen and stomach in Korea. In this study, we conducted simultaneous analysis of the 9 marker components, liquiritin apioside, liquiritin, ginsenoside Rg1, liquiritigenin, ginsenoside Rb1, glycyrrhizin, atractylenolide III, atractylenolide II, and atractylenolide I in Sagunja-tang using a liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS/MS). Marker compounds were separated on a Waters Acquity UPLC BEH $C_{18}$ analytical column ($2.1{\times}100mm$, 1.7 mm) and the column was maintained at $45^{\circ}C$. The mobile phase consists of 0.1% (v/v) aqueous formic acid and acetonitrile with gradient condition. The LC-MS analysis was performed using a Waters ACQUITY TQD LC-MS/MS system with multiple reaction monitoring (MRM) method in the positive and negative modes. The calibration curves of the nine marker components showed good linearity with coefficient of determination ${\geq}0.9984$ within tested range. The limits of detection and limits of quantification values were 0.27-2.42 ng/mL and 0.81-7.27 ng/mL, respectively. The concentrations of tested 9 analytes in the lyophilized Sagunja-tang sample using the established LC-ESI-MS/MS MRM method were detected up to 16.593 mg/g. These results can be useful as a basic data for the quality control of an oriental medicine prescriptions.

• YAKHAK HOEJI
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• v.51 no.3
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• pp.174-178
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• 2007

A reverse-phase high performance liquid chromatography method with electrospray ionization and detection by mass spectrometry is described for the simultaneous determination of doxifluridine and its active metabolite 5-flu-orouracil (5-FU) in monkey serum. The method has greater sensitivity and simpler process than previous published methods with good accuracy and precision. A proper liquid/liquid extraction was used to extract simultaneously doxifluridine and 5-FU which has considerable difference in the polarity. Extracts were analyzed using LC/MS/MS providing a short analysis time within 5 min. The lower limit of quantification was validated at 10.0 ng/ml of serum for both doxifluridine and 5-FU. Accuracy and precision of quality control (QC) samples for both analytes met FDA Guidance criteria of ±15% for average QC accuracy with coefficients of variation less than 15%. The method will be applicable for preclinical studies and bioequivalence studies.

• Korean Journal of Veterinary Service
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• v.45 no.3
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• pp.237-242
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• 2022

The simultaneous analysis of mycotoxins using LC-MS/MS, a food official analysis method, was applied with compound feed for pets with high consumer preferences. In this study, the linearity of all calibration curves showed good linearity of 0.99 or more. and both the accuracy (recovery rate) and precision (repeatability) criteria of the concentration range for each mycotoxin in the National Agricultural Products Quality Management Service's Validation and Verification Guidelines were met. And as a result of analyzing FAPAS QCM in the same way, it was assesed that the z-scores of Aflatoxin B₁, Ochratoxin A, Zearalenone, and Fumonisin B₁, were within ±2 range. This study showed that the application of the food official analysis method to compound feed for pets is suitable.