• Journal of the Korean Chemical Society
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• v.58 no.6
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• pp.535-542
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• 2014

A simple and efficient preconcentration method was developed using three-phase liquid phase microextraction prior to HPLC-UV for simultaneous extraction and determination of tetracycline antibiotics (tetracycline, oxytetracycline, and chlortetracycline). The tetracycline antibiotics were separated simultaneously on a column ($C_8$, $3.0{\times}150mm$, $3{\mu}m$) with high selectivity and sensitivity using gradient elution. Under optimized conditions (extraction solvent, heptanal; pH of donor, 9.0; pH of acceptor, 1.0; stirring speed, 700 rpm; NaCl salt, 0%; and extraction time, 60 min), enrichment factors (EF) were between 5.6 and 22.3. The limit of detection (LOD) and limit of quantitation (LOQ) in the spiked urine matrix were in the concentration range of $0.08{\sim}0.8{\mu}g/mL$ and $0.4{\sim}1.6{\mu}g/mL$, respectively. The calibration curves were linear within the range of $0.1{\sim}32{\mu}g/mL$ with the square of the correlation coefficient being more than 0.995. The precision (as a relative standard deviation, RSD) and accuracy (as a relative recovery) within working range were 1.3~9.1% and 84~118%, respectively.

• Journal of Food Hygiene and Safety
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• v.22 no.2
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• pp.88-92
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• 2007

Isopropylthioxanthone(ITX) is used as a photoinitiator In UV-cured inks, triggering the radical polymerization of the acrylic component of such inks and thus causing the liquid ink film to cure. Recently ITX was detected in carton packed food in Italy. In order to cope with risk issues of overseas and acquire monitoring data on ITX, we have established the method using HPLC/FLD for ITX analysis after reviewing parameters of the analytical methods. Limit of detection (LOD) and limit of quantification (LOQ) were 0.02 ppb and 0.1 ppb, and linearity and RSD (%) were 0.9991 and 1.09, respectively. We have investigated ITX levels migrated to food on 87 commercial products packed in carton and ITX was not detected any food. Therefore it is supposed that UV-cured ink containing ITX as photoinitiator is not currently used in printing of carton pack in Korea.

• Analytical Science and Technology
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• v.33 no.6
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• pp.233-239
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• 2020

This study was performed to develop an analytical method using Carrez reagents as the precipitant to effectively and easily remove proteins and lipids while pretreating samples for the simultaneous determination of preservatives, including dehydroacetic acid (DHA), sorbic acid (SA), benzoic acid (BA), methyl ρ-hydroxybenzoate (MP), ethyl ρ-hydroxybenzoate (EP), propyl ρ-hydroxybenzoate (PP), isopropyl ρ-hydroxybenzoate (IPP), butyl ρ-hydroxybenzoate (BP), and isobutyl ρ-hydroxybenzoate (IBP). The effective selectivity was determined by HPLC separation analysis for nine preservatives in the test solution, after removing interfering materials such as lipids and proteins. The method developed in this study showed excellent linearity at 0.999 or higher. The limit of detection (LOD) ranged from 0.09 to ~0.12 mg/L and the limit of quantitation (LOQ) was ~0.280.37 mg/L. The results of the recovery test on processed foods, including pickles, cheeses, processed meat products, beverages, sauces, and emulsified foods showed DHA, SA, BA, MP, EP, IPP, PP, IBP, and BP at 90.9~107.7 %, 85.4~113.7 %, 90.7~111.6 %, 84.5~111.2 %, 81.3~110.9 %, 82.5~102.2 %, 81.1~110.0 %, 80.9~109.0 %, and 82.4~110.3 %, respectively. The probability of the simultaneous analytical method developed in this study as a quantitative method was confirmed for various processed foods.

• The Korean Journal of Pesticide Science
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• v.13 no.3
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• pp.133-147
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• 2009

In order to develop the simultaneous analytical method for pesticide residues which ones in soil are rapidly and inexpensively measured by, many analytical methods for individual pesticide residue and several methods for multi-pesticide residues in agricultural commodities and food were reviewed. Various gas chromatographic conditions and pre-treatment procedures were intensively investigated and modified. And then new optimum procedure was established and its proficiency was validated. The response on detectors of simultaneous determination of 180 pesticides out of pesticides used in Korea was tested. The number of pesticides that their limits of detection (LOD) equal or lower than $0.05\;mg\;kg^{-1}$ were 137 pesticides on ECD, 170 pesticides on NPD and 179 pesticides on ECD/NPD integrated. The retention times of most pesticides ranged appropriately between 10 minutes and 40 minutes in the proposed chromatographic conditions. But about 90 pesticides eluded between 20 minutes and 30 minutes and so they were not resolved enough. In partition with dichloromethane, ethyl acetate/hexane (1:1) and ethyl acetate, number of pesticides whose extraction efficiency ranged from 70% to 120%, were 163, 154 and 147, respectively.

• Journal of Environmental Health Sciences
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• v.46 no.3
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• pp.324-334
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• 2020

Objectives: This study was conducted to estimate the related health risk by investigating the content of biogenic amines (BAs) in commercial fermented alcoholic beverages. Methods: Ninety-seven samples, including takjus (34), fruit wines (26), distilled liquors (20) and beers (17) were purchased in Gangwon-do (Province) in 2019. The eight BAs (putrescine, cadaverine, spermine, spermidine, tyramine, β-phenylethylamine, histamine, and tryptamine) were analyzed by high performance liquid chromatograph (HPLC) after extraction (0.4 M HClO₄), pigment removal (carbon cartridge) and derivatization (1% dansylchloride). The health risk of exposure to BAs due to ingestion of commercial fermented alcoholic beverages was estimated as the margin of exposure (MOE). Results: Various BAs were detected in takju, fruit wine, distilled liquor and beer. Putrescine (not detected (ND)-12.60 mg/L), cadaverine (ND-5.45 mg/L), tyramine (ND-8.34 mg/L), β-phenylethylamine (ND-13.73 mg/L), histamine (ND-7.96 mg/L), and tryptamine (ND-19.00 mg/L) were found in takju. Putrescine (ND-15.34 mg/L), cadaverine (ND-7.90 mg/L), β-phenylethylamine (ND-3.06 mg/L), histamine (ND-9.68 mg/L), and tryptamine (ND-14.06 mg/L) were identified in fruit wine. Putrescine (less than limit of detection (

• Journal of the Korean Chemical Society
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• v.56 no.5
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• pp.583-590
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• 2012

The HF (Hollow fiber) extraction method was optimized to analysis seven species of pesticides in aqueous sample and analyzing samples by GC/MS. Hollow fiber extraction showed good efficiency when it was conducted under these conditions: organic solvent was toluene and agitation speed was 1200 rpm. The 15% concentration of NaCl was optimized when it was experimented between 5% and 25%. The equilibrium time was determined at 15 minutes. The pH 5 showed the best effect on the extraction efficiency. The linearities of calibration curves of seven species were good with correlation of regression ($r^2$) over 0.995 when they were experimented over a concentration range of $5{\mu}g/L$ to $50{\mu}g/L$. The analytical data exhibited the detection of limits (LODs) range of $0.37{\mu}g/L$ to $1.23{\mu}g/L$ and the limit of quantification (LOQs) range of $1.19{\mu}g/L$ to $3.91{\mu}g/L$. The optimized HF-LPME extraction method provides a simple and effective preparation and requires small amount of organic solvents and samples compared to conventional pre-treatment methods.

• Journal of Food Hygiene and Safety
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• v.31 no.3
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• pp.194-200
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• 2016

Aflatoxins and ochratoxin A (AFTs and OTA) are secondary fungal metabolites produced by several moulds, mainly by Aspergillus flavus by Aspergillus ochraceus and Penicillium verrucosum, and these toxins can be transferred to animals and humans through the ingestion of contaminated feed and food. This study was to develop the analytical method for determination the levels of AFTs ($B_1$, $B_2$, $G_1$ and $G_2$) and OTA in pork. The AFTs and OTA were analyzed simultaneously by electrospray ionization in positive ion mode and mass reaction monitoring (MRM) after solid phase extract (SPE) columns clean-up. Performance characteristics, such as accuracy, precision, linear range, limit of detection (LOD) and quantification (LOQ), were also determined. Matrix-matched standard calibration was used for quantification, obtaining the recoveries in the range of 67.3~108.2% with the relative standard deviations of < 20%. Limits of detection and quantification were also estimated, obtaining the limits of quantification ranged in $0.7{\sim}1.3{\mu}g/kg$. The results of the inter-day study, which was performed with pork samples for 3 days, showed an accuracy of 92.0~109.9%. The precisions (expressed as relative standard deviation values) for the inter day variation were 2.6~17.8%. The method developed in this study was able to carry out the analysis with the satisfactory intensity and accuracy.

• Herbal Formula Science
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• v.21 no.2
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• pp.133-143
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• 2013

Objectives : We carry out the simultaneous quantification for quality control of four components in Bangpungtongseong-san (BPTSS) sample. In addition, we assessed the antioxidant effects of BPTSS sample. Methods : The used column for separation and analysis of four compounds was Luna C18 column and column oven temperature was maintained at $40^{\circ}C$. The mobile phase for simultaneous determination consisted of two solvent systems, 1.0% acetic acid in water and 1.0% acetic acid in acetonitrile. High performance liquid chromatography-photodiode array (HPLC-PDA) method for analysis was performed at a flow rate of 1.0 mL/min with PDA detection at 254 and 280 nm. The injection volume was 10 ${\mu}L$. The antioxidant activities of BPTSS were evaluated by measuring free radical scavenging activities on 2,2'-Azinobis-3-ethyl-benzothiazoline-6-sulfonic acid (ABTS) and 1-1-diphenyl-2-picrylhydrazyl (DPPH). The inhibitory effects on low-density lipoprotein (LDL) oxidation were evaluated by the formation of thiobarbituric acid relative substances (TBARS) and relative electrophoretic mobility (REM). Results : Calibration curves were acquired with $r^2{\geq}0.9999$. The values of limit of detection (LOD) and quantification (LOQ) were 0.06-0.29 ${\mu}g/mL$ and 0.20-0.98 ${\mu}g/mL$, respectively. The amounts of geniposide, liquiritin, baicalin, and glycyrrhizin in BPTSS were 5.06, 7.33, 27.56, and 7.81 mg/g, respectively. The BPTSS showed the radical scavenging activity in a dose-dependent manner. The concentration required for 50% reduction (RC50) against ABTS and DPPH radicals were 72.51 ${\mu}g/mL$ and 128.49 ${\mu}g/mL$. Furthermore, GMGHT reduced the oxidation properties of LDL induced by CuSO4. Conclusions : The established HPLC-PDA method will be helpful to improve quality control of BPTSS. In addition, BPTSS has potentials as therapeutic agent on anti-atherosclerosis.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.53 no.2
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• pp.224-232
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• 2008

The health benefits associated with tea consumption have resulted in the wide inclusion of green tea extracts in botanical dietary supplements, which are widely consumed as adjuvants for complementary and alternative medicines. Tea contains polyphenols such as catechins or flavan-3-ols including (-)-epicatechin (EC), (-)-epigallocatechin (EGC), (-)-epicatechin gallate (ECG), and (-)-epigallocatechin gallate (EGCG), as well as the alkaloid, caffeine. The contents of catechins and caffeine in green tea are considered as a standard of quality evaluation of green tea. Therefor, the purpose of this study was to investigate the most suitable HPLC condition for simultaneous determination of catechins and caffeine in green tea extracts. The efficient HPLC analytical condition of catechins and caffeine contained green tea extracts was developed. The gradient elution employed a $250\;mm\;{\times}\;4.6\;mm$ i.d. YMC-pak ODS-AM 303 column. The gradient system was used two mobile phases. A gradient elution was performed with mobile phase A, consisting of 0.1% aqueous phosphoric acid, and mobile phase B, comprising 100% MeOH, and delivered at a flow rate of 1 mL/min as follows: $0{\sim}25\;min$, 80% A; $26{\sim}50\;min$, $80{\sim}70%$ A; 51 min, 80% A. $51{\sim}55\;min$, 80% A. The UV detection wavelength was set at 280 nm. The limit of detection (LOD) for catechins and caffeine standards were under 50 ng/mL.

• Korean Journal of Food Science and Technology
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• v.42 no.5
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• pp.632-636
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• 2010

The level of ${\gamma}$-aminobutyric acid (GABA) in pigmented rice was quantitatively and qualitatively determined by high pressure liquid chromatography/fluorescence detection (HPLC/FLD). In this study, the recovery rate and limit of detection (LOD) of GABA were 122.4${\pm}$2.4% and 0.23 ${\mu}g/g$, respectively. The geminating pigmented rice samples, which were harvested in Paju, Korea, were soaked in water at $18^{\circ}C$ for 20 hr. After soaking, the samples were germinated at $30^{\circ}C$ for about 24 hr. GABA content was highest (293.0 ${\mu}g/g$) in the germinated red rice. Furthermore, GABA levels in the germinated rice increased significantly by up to 11.1 and 24.7-fold as compared to non-germinated rice and milled rice, respectively. The GABA concentrations of non-germinated rice, with the exception of red rice, were significantly higher than those of milled rice by 7.6-20.6-fold.