• Journal of Food Hygiene and Safety
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• v.28 no.3
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• pp.247-251
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• 2013

The objective of present study was to develop a simultaneous determination method of 5 medical compounds, including beclomethasone, dexamethasone, prednisolone, ketoprofen, phenylbutazone in foods, using LC-MS/MS. To optimize MS analytical condition of 5 compounds, each parameter was established by MRM mode. The chromatographic separation was achieved on a C18 column successfully, with a mobile phase made up of A (0.1% formic acid) and B (0.1% formic acid in acetonitrile), at a flow rate of 0.3 mL/min for 17 min with a gradient elution. LOD and LOQ of 5 compounds were in the range of 0.40~4.60 ng/mL and 0.81~11.46 ng/mL, respectively. As a result of analyzing the three concentrations of the standard mixture added to blank samples, the results showed that the mean recovery rate of 5 compounds was in the range of 81.52~103.83%, and RSD (%) of Intra- and Inter-day assay were 0.52-10.45. Since relatively fine selectivity, accuracy and reproducibility were shown in this qualified experimental method, it could be utilized efficiently to investigating those 5 compounds to see if it is added to food products illegally.

• Journal of the Korean Chemical Society
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• v.54 no.5
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• pp.523-532
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• 2010

The proposed method is simple, sensitive and specific Liquid chromatography-tandem mass spectrometry (LCESI-MS/MS) method for the quantification of Entacapone (EA) in human plasma using Entacapone-d10 (EAD10) as an internal standard (IS). Chromatographic separation was performed on Zorbax SB-C18, $2.1{\times}50\;mm$, $5\;{\mu}m$ column, mobile phase composed of 10 mM Ammonium formate (pH 3.0): Acetonitrile (60:40 v/v), with a flow-rate of 0.7 mL/min, followed by Liquid-liquid extraction. EA and EAD10 were detected with proton adducts at m/z $306.1{\rightarrow}233.1$ and $316.3{\rightarrow}233.0$ in multiple reaction monitoring (MRM) positive mode respectively. The method was validated over a linear concentration range of 1.00 - 2000.00 ng/mL with correlation coefficient ($r^2$) $\geq$ 0.9993. Intra and inter-day Precision within 3.60 to 7.30 and 4.20 to 5.50% and Accuracy within 97.30 to 104.20 and 98.30 to 105.80% proved for EA. This method is successfully applied in the bioequivalence study of healthy Indian human volunteers.

• Korean Journal of Veterinary Service
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• v.36 no.4
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• pp.303-309
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• 2013

This study was conducted to determine the content of 7 mycotoxins (aflatoxin $B_1$, $B_2$, $G_1$, $G_2$, $M_1$, ochratoxin A and zearalenone) using LC-MS/MS in pork available on the Korean markets. The analysis was carried out using following conditions; C18 column ($2.1{\times}100mm$, $1.7{\mu}m$), mobile phase composed of $H_2O$ (0.1 mM $NH_4Ac$ 0.01% HCOOH) : Methanol (0.1 mM $NH_4Ac$ 0.01% HCOOH), binary pump at a flow rate of 0.5 mL/min and $2{\mu}L$ of injection volume, MS/MS detector with ESI positive and negative mode. The quantication of mycotoxins was based on matrix-matched calibration curves with a correlation coefficient in excess of 0.99 for the 7 mycotoxins. The dectection limits were ranged 0.74~2.13 ng/g, with mean recoveries between 73.10~97.46% except aflatoxin $B_1$ (61.31%). We also monitored mycotoxin residues in 208 pork samples. The test results, mycotoxins were not found except one sample. Ochratoxin A in one sample of the test samples was detected below the quantification limit.

• Journal of Food Hygiene and Safety
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• v.28 no.4
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• pp.376-380
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• 2013

Determination of PFOS in instant food packing materials by LC-MS/MS was developed. The procedure involves an extraction of the Food Packing Materials with 100% methanol soxcelet extraction method. The LC separation was performed by Hypersil Gold ($150mm{\times}2.1mm$ 5 um) with mobile phases of 2 mM amoniumacetate solution and acetonitrile. The Mass spectral acquisition was done in negative ESI/SRM using the TSQ Quantum Ultra. With this method, good linear relationship, sensitivity and reproducibility were obtained. The rate of recoveries of PFOS from paper material spiked with 1.0 ug/L were 99.84%, respectively. The limit of quantitation and limit of detection were below 0.03 ug/L and 0.009 ug/L. The method had been applied to determination of PFOS in instant food packing materials.

• Journal of Food Hygiene and Safety
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• v.33 no.2
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• pp.118-123
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• 2018

The objective of this study was to develop a sensitive method for the identification and determination of nitrovin in fishery products by using a solid-phase extraction (SPE), as performed with a liquid chromatography-tandem mass spectrometry (LC-MS/MS). The samples were extracted with a mixture of acetonitrile and water, and were then defatted with acetonitrile saturated hexane, after which further clean-up was accomplished with SPE on the hydrophilic-lipophilic balance (HLB) cartridges. The analytes were subsequently ionized in the positive mode of an electrospray ionization (ESI), and where thereby detected in a process of multiple reaction monitoring (MRM). The linearity (expressed as correlation coefficients) of the matrix calibration curves was > 0.985. The limit of the quantification for the nitrovin was measured at 0.001 mg/kg. The accuracy (expressed as average recovery) was noted between 72.1 and 122%. The precision (expressed as coefficient variation) was noted from 2.9 to 16.9%. According to the CODEX CAC/GL-71 guideline accuracy, precision, linearity, and limit of detection were determined in three matrices (which were flatfish, eel and shrimp). The proposed method was suitable for analyzing the associated nitrovin residues. This application and result can also be a factor to contribute to the non-detection drugs management in fishery products.

• Korean Journal of Environmental Agriculture
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• v.41 no.2
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• pp.135-151
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• 2022

BACKGROUND: The β-agonists known as phenyl ethanolamine derivatives have a conjugated aromatic ring with amino group. They are used as tocolytic agents and bronchodilator to human and animal generally, and some of them are used as growth promoters to livestock. METHODS AND RESULTS: β-agonists in samples were extracted by 0.4 N perchloric acid and ethyl acetate. The target compounds were analyzed by liquid chromatography-electrospray tandem mass spectrometry (LC-ESI-MS/MS). Validation of method was performed according to CODEX guidelines (CAC/GL-71). The matrix matched calibration gave correlation coefficients>0.98, and the obtained recoveries were in the range of 62.0-109.8%, with relative standard deviation ≤ 20.1%. In addition, a survey was performed to inspect any residual β-agonist from 100 samples of livestock and fishery products and ractopamine was detected in one of the 100 samples. CONCLUSION(S): In this study, we established the analytical method for β-agonists through using the expanded target compounds and samples. And we anticipate that the established method would be used for analysis to determine veterinary drug residues in livestock and fishery products.

• Mass Spectrometry Letters
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• v.9 no.1
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• pp.30-36
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• 2018

A quantitation method for free amino acids in human serum was developed using a stepwise-dilution method and a bimodal cation exchange (CEX)/hydrophilic interaction liquid chromatography (HILIC)-tandem mass spectrometry system equipped with an electrospray ionization source (ESI/MS/MS). This method, which was validated using quality control samples, was optimized for enhanced selectivity and sensitivity. Dithiothreitol (DTT) was used as a reducing agent to prevent the oxidation of a serum sample ($50{\mu}L$), which was then subjected to stepwise dilution using 3, 30, and 90 volumes of acetonitrile containing 0.1% formic acid. Chromatographic separation was performed on an Imtakt Intrada Amino Acid column ($50mm{\times}3mm$, $3{\mu}m$) in mixed mode packed with CEX and HILIC ligands embedded in the stationary phase. Underivatized free amino acids were eluted and separated within 10 min. As a result of the validation, the precision and accuracy for the inter- and intraday assays were determined as 2.11-11.51% and 92.82-109.40%, respectively. The lowest limit of quantification (LLOQ) was $0.5-4.0{\mu}g/mL$ and the matrix effect was 80.22-115.93%. The proposed method was successfully applied to the quantitative analysis of free amino acids in human serum.

• BMB Reports
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• v.47 no.5
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• pp.292-297
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• 2014

Age-related macular degeneration (AMD) is the leading cause of blindness in the world. Evidence indicates that the suppression of the ubiquitin-proteasome system (UPS) contributes to the accumulation of toxic proteins and inflammation in retinal pigment epithelium (RPE), the functional abnormalities and/or the degeneration of which are believed to be the initiators and major pathologies of AMD. To identify new protein associations with the altered UPS in AMD, we used LC-ESI-MS/MS to perform a proteomic analysis of the aqueous humor (AH) of AMD patients and matched control subjects. Six UPS-related proteins were present in the AH of the patients and control subjects. Four of the proteins, including 26S proteasome non-ATPase regulatory subunit 1 (Rpn2), were increased in patients, according to semi-quantitative proteomic profiling. An LC-MRM assay revealed a significant increase of Rpn2 in 15 AMD patients compared to the control subjects, suggesting that this protein could be a biomarker for AMD.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2018.04a
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• pp.61-61
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• 2018

Buckwheat is a important vegetable in asia for long time. Recently, Buckwheat has attracted attention to its potential for health benefit and especially as a gluten-free food. Conventional buckwheat studies have focused on seeds and sprouts, but we studied the components of the aerial parts and roots of buckwheat after harvesting. Therefore, we hope that this research will be a basic study to expand the application range of buckwheat plants which are discarded after harvesting. The ethanol extracts of aerial part and roots of buckwheat (Daegwan, Yangjul) were analysed using high performance liquid chromatography (HPLC). Rutin was detected as the major compound in Daegwan, Yangjul aerial part and Daegwan root extracts, except yangjul root extract. So we analysed Yangjul root extract using liquid chromatography-mass spectrometry (LC-MS) and then obtained the informations about the components in Yangjul root extract. Yangjul root extract was analysed by $LC-MS^n$ in negative ESI mode within the range m/z 150-2000 amu. Totally, four components was found in the Yangjul root extract and obtained the fragments ion patterns of ones. Further study, we have to confirm the structure of components in Yangjul root extract and try to more biological activity test the components for development as useful food or cosmetic ingredients.

• Analytical Science and Technology
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• v.23 no.6
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• pp.524-530
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• 2010

Chloramphenicol is one of the most effective antibiotics for treatment of food-producing animals for typhoid fever. However, it has been reported that it caused severe side effects such as aplastic anemia in human, therefore the use of chloramphenicol for food-producing animal is prohibited by European Union and other countries. In this study, the analytical method using isotope dilution liquid chromatography-mass spectrometry (ID-LC/MS) was established for accurate determination of chloramphenicol in meat. Chloramphenicol was extracted with ethylacetate from porcine and solid phase extraction cartridge was used for enhancing the recovery. The residue of chloramphenicol in porcine was analyzed using the liquid chromatography mass spectrometer (LC/MS) interfaced with electrospray ionization source. Analysis was performed in negative mode with selected reaction mornitoring mode at m/z 321${\rightarrow}$257 of $[M-H]^-$ ${\rightarrow}$ $[M-H-(HCOCl)]^-$ and m/z 326 ${\rightarrow}$ 262 channels for its isotope. The established method was tested using fortified samples at the level of 0.2 1, 10, $25\;{\mu}g$/kg and analytical results agreed with the gravimetrically fortified values within their uncertainties. This method was validated by analyzing a certified reference material, BCR 445, from IRMM (Institute for Reference Materials and Measurement). Our measurement values agreed with the certified value within their uncertainties. The uncertainty of our measured value was much lower than that the certified value from IRMM.