• Korean Journal of Veterinary Research
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• v.63 no.3
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• pp.23.1-23.9
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• 2023

This study was conducted to investigate tiamulin (TML) residues in the edible tissues of orally dosed broiler chickens and to re-establish the withdrawal time (WT). Thirty-six healthy Ross broiler chickens were administered 0.5 (TML-1) and 2.5 kg (TML-2) per ton feed, respectively, of the drug containing TML 78 g/kg for 10 days. Twenty-four tissue samples were collected from 6 chickens in each of the TML-1 and TML-2 groups on 0, 1, 3, and 5 days after drug administration, respectively. The residual concentrations of TML were measured using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The correlation coefficient of the calibration curves was 0.9978 to 0.9998, and the limits of detection and the limits of quantification (LOQ) were in the range of 0.03 to 0.06, and 0.1 to 0.2 ㎍/kg, respectively. Recoveries ranged between 89.0% to 116.7%, and the coefficients of variation were less than 13.9%. After the drug administration, TML in the TML-1 and TML-2 groups was detected above the LOQ in 1 and 6 samples of liver, respectively, at day 0, and in 1 liver sample from both groups on day one. At 3 days after administration, TML was detected below the LOQ in all samples of TML-1 and TML-2. The calculated WT of TML in both TML-1 and TML-2 using the WT calculation program WT 1.4 was 0 days. In conclusion, the developed analytical method is suitable for detection, and the calculated WT of TML in poultry edible tissues is shorter than the current recommended WT of 7 days for TML in broiler chickens.

• Korean Journal of Environmental Agriculture
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• v.36 no.4
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• pp.269-278
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• 2017

BACKGROUND: The objective of this study was to evaluate screening method of residual multi pesticides in dead birds by Orbitrap high resolution mass spectrometry (HRMS) to identify the cause of death for birds. METHODS AND RESULTS: Extraction and clean-up method of residual pesticides in liver of dead birds was used QuEChERS (Quick Easy Cheap Effective Rugged and Safe) and method validations was conducted using liquid chromatography and gas chroamtography with triple-quadrupole mass spectrometer (LC/MS/MS and GC/MS/MS) Also, we were evaluated screening method for the determination of residual pesticides in liver of dead birds by LC and GC Orbitrap Mass Spectrometry. Results of method validations, Correlation coefficients of the matrix matched calibration curves were >0.978, and the method detection limits (MDLs) and limits of quantitation (LOQ) were 2.8~72.1 ng/g (18.4 ng/g on average) and 9.0~230 ng/g (58.5 ng/g on average). The accuracy ranged from 69.1%to 130% (103% on average), and the precision values were less than 14.8%(3.8%on average). The screening of residual pesticides in liver of dead birds by LC and GC Orbitrap HRMS was detected monocrotophos, carbofuran, carbosulfan, deltametrin, benfuracarb, carbofuran, phosphamidon, prochloraz in investigated samples. CONCLUSION: This results showed that accurate mass were extraction of residual pesticides in dead birds by Orbitrap HRMS. It suggested that this screening method is applicable to the residual pesticide analysis for the cause of death as a main tool.

• Toxicological Research
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• v.31 no.3
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• pp.255-264
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• 2015

Heterocyclic amines (HCAs) and acrylamide are unintended hazardous substances generated by heating or processing of foods and are known as carcinogenic and mutagenic agents by the animal experiments. A simple method was established for a rapid and accurate determination of 12 types of HCAs (IQ, MeIQ, Glu-P-1, Glu-P-2, MeIQx, Trp-P-1, Trp-P-2, PhIP, $A{\alpha}C$, $MeA{\alpha}C$, Harman and Norharman) and acrylamide in three food matrices (non-fat liquid, non-fat solid and fat solid) by isotope dilution liquid chromatography-tandem mass spectrometry (LC-MS/MS). In every sample, a mixture of internal standards including $IQ-d_3$, $MeIQx-d_3$, $PhIP-d_3$, $Trp-P-2-^{13}C_2-^{15}N$ and $MeA{\alpha}C-d_3$ was spiked for quantification of HCAs and $^{13}C_3$-acrylamide was also spiked for the analysis of acrylamide. HCAs and acrylamide in sample were extracted with acetonitrile and water, respectively, and then two solid-phase extraction cartridges, ChemElut: HLB for HCAs and Accucat: HLB for acrylamide, were used for efficiently removing interferences such as pigment, lipid, polar, nonpolar and ionic compounds. Established method was validated in terms of recovery, accuracy, precision, limit of detection, limit of quantitation, and linearity. This method showed good precision (RSD < 20%), accuracy (71.8~119.1%) and recovery (66.0~118.9%). The detection limits were < 3.1 ng/g for all analytes. The correlation coefficients for all the HCAs and acrylamide were > 0.995, showing excellent linearity. These methods for the detection of HCAs and acrylamide by LC-MS/MS were applied to real samples and were successfully used for quantitative monitoring in the total diet study and this can be applied to risk assessment in various food matrices.

• Korean Journal of Food Science and Technology
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• v.7 no.1
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• pp.15-21
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• 1975

Soong-Neung is a Korean traditional beverage served after meals and is made from cooked and roasted rice produced on the bottom of the container during the rice cooking process. The volatiles from the extract of cooked and roasted rice were separated into pyrazine and carbonyl fractions and qualitatively investigated. The pyrazine fraction was characterized by gas chromatography and combined gas chromatography-mass spectrometry and five pyrazines were positively identified. Pyrazine compounds identified are 2-methylpyrazine, 2,3-dimethylpyrazine, 2,5-dimethylpyrazine, 2-ethyl-5-methylpyrazine and 2-ethyl-3-methylpyrazine. Carbonyls were converted to their 2,4-dinitrophenylhydrazones and identified by gas chromatography, combined gas chromatography-mass spectrometry and thin layer chromatography. Acetaldehyde, propionaldehyde, iso-butyraldehyde and iso-valeraldehyde were positively identified in the carbonyl compounds. The aroma of the fractions indentified as 2,3-dimethylpyrazine and 2,5-dimethylpyrazine had a nut-like or roasted cereal-like flavor, which is one of the characteristic flavors of Soong-Neung.

• Journal of Microbiology and Biotechnology
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• v.19 no.11
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• pp.1348-1354
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• 2009

Bioconversion of the isoflavonoid genistein to 2'-hydroxygenistein (2'-HG) was performed using isoflavone 2'-hydroxylase (CYP81E1) heterologously expressed in yeast. A monohydroxylated product was analyzed by liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS) and NMR spectrometry and was identified as 2'-HG. An initial bioconversion rate of 6% was increased up to 14% under optimized conditions. After recovery, the biological activity of 2'-HG was evaluated. Bioconverted 2'-HG showed higher antioxidant activity against 1,1-diphenyl-2-picryl hydrazine (DPPH) and 2,2'-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radicals than did genistein. Furthermore, 2'-HG exhibited greater antiproliferative effects in MCF-7 human breast cancer cells than did genistein. These results suggest that 2'-hydroxylation of genistein enhanced its antioxidant activity and cell cytotoxicity in MCF-7 human breast cancer cells.

• Korean Journal of Food Science and Technology
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• v.43 no.5
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• pp.544-552
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• 2011

The purpose of this study was to develop an analytical method for determining 15 polycyclic aromatic hydrocarbons (PAHs) of EU priority using gas chromatography (GC)-tandem mass spectrometry (MS). The PAHs in ground coffee were analyzed after being extracted using methods such as saponification-liquid-liquid extraction, Soxhlet extraction, and solid-liquid extraction. The solid-liquid extraction method showed the greatest repeatability and most efficient reduction of the matrix effect. GC-tandem MS for the quantification of the 15 PAHs showed better resolution and lower limit of detections (LODs) than GC-MS-selected ion monitoring (SIM) and high performance liquid chromatography with fluorescence detector. LODs of this method for the ground coffee types were 0.002-0.1 ${\mu}g/kg$ and limit of quantifications (LOQs) were 0.006-0.2 ${\mu}g/kg$ The recoveries ranged from 52.6 to 93.3%. Forty-six commercial types of ground coffee were analyzed to determine their PAHs contamination levels. PAHs concentration ranged from ND to 5.988 ${\mu}g/kg$. This study was conducted with toxicity equivalence factors, the U.S. EPA recommendation to identify dietary risks for PAHs in different types of coffee. The estimated average daily dose of PAHs was $5.24{\times}10^{-8}$ mg/kg body weight/day.

• Mycobiology
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• v.49 no.4
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• pp.434-437
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• 2021

In our ongoing search for new secondary metabolites from fungi, a basidiomycete fungus Irpex consors was selected for mycochemical investigation, and three new zwitterionic alkaloids (1-3) and five known compounds (4-8) were isolated from the culture broth (16 l) of I. consors. The culture filtrate was fractionated by a series of column chromatography including Diaion HP-20, silica gel, and Sephadex LH-20, Sep-Pak C₁₈ cartridge, medium pressure liquid chromatography (MPLC), and high pressure liquid chromatography (HPLC) to yield eight compounds (1-8). The structures of the isolated compounds were elucidated by the interpretation of nuclear magnetic resonance (NMR) spectra and high-resolution mass spectrometry (HR-MS). Their antioxidant and antibacterial activities were examined. The zwitterionic structures of three new sesquiterpene alkaloids (1-3) were determined together with five known compounds identified as stereumamide E (4), stereumamide G (5), stereumamide H (6), stereumamide D (7), and sterostrein H (8). This is the first report of the zwitterionic alkaloids in the culture broth of I. consors. Three new zwitterionic alkaloids were named as consoramides A-C (1-3).

• Korean Journal of Medicinal Crop Science
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• v.27 no.3
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• pp.208-217
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• 2019

Background: In the present study, we identified two cytotoxic compounds from the root of Rumex crispus L. using a bioassay-based method. Methods and Results: Compared with the other fractions, the diethyl ether ($Et_2O$) fraction of R. crispus root extract exhibited the strongest of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging effect [scavenging concentration 50% $(SC_{50})=63.8{\pm}1.47{\mu}g/m{\ell}$], nitric oxide (NO) production inhibitory effect on the mouse macrophage cell line RAW264.7 [inhibitory concentration 50% $(IC_{50})=60.9{\pm}7.52{\mu}g/m{\ell}$] and cytotoxicity effect on the human hepatoma cell line, HepG2 [lethal concentration 50% $(LC_{50})=115.4{\pm}1.86{\mu}g/m{\ell}$]. According to the bioassay-based method, two cytotoxic compounds were purified from the $Et_2O$ fraction by using column chromatography and preparative high performance liquid chromatography (prep-HPLC). These two compounds were identified as parietin and chrysophanol by using nuclear magnetic resonance (NMR) and liquid chromatography quadruple time of flight mass spectrometry (LC-QTOF-MS). In addition, both parietin and chrysophanol exhibited a cytotoxicity effect on HepG2 cells, their $LC_{50}$ values were $169.1{\pm}17.67{\mu}M$ and $111.5{\pm}6.62{\mu}M$, respectively. Conclusions: Parietin and chrysophanol isolated from the $Et_2O$ fraction of the R. crispus root extract showed cytotoxicity in HepG2 cell.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.10
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• pp.1441-1446
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• 2009

Composition of intramuscular lipids, phospholipid classes and phospholipid molecular species in traditional Chinese duck meat products was investigated. Free fatty acids and phospholipids were identified and quantified by gas and high performance liquid chromatography, and phospholipid molecular species were determined by mass spectrometry. The results showed that raw duck meat had high quantities of phosphatidylethanolamine and phosphatidylcholine. The percentages of phospholipid classes decreased during three kinds of processing of duck meat products. A selective degradation of phospholipid molecular species with polyunsaturated fatty acids was found in dry-cured duck, but was not found in roasted and water-boiled duck products.

• BMB Reports
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• v.45 no.8
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• pp.442-451
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• 2012

Milk is an important fluid in glycobiology because it contains a number of short carbohydrate chains either free or as glycoconjugates. These compounds as a class are the most abundant component and benefit the infant by developing and maintaining the infant's gut flora. New and emerging methods for oligosaccharide analysis have been developed to study milk. These methods allow for the rapid profiling of oligosaccharide mixtures with quantitation. With these tools, the role of oligosaccharide in milk is being understood. They further point to how oligosaccharide analysis can be performed, which until now has been very difficult and have lagged significantly those of other biopolymers.