• Asian-Australasian Journal of Animal Sciences
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• 제14권3호
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• pp.378-381
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• 2001

Sulfamethazine has been widely used in swine for prevention or treatment of infections. Recently, the safety of the drug to consumers has been questioned because of carcinogenic effects. To prevent unwanted drug residues entering the human food chain, both government authorities and industries have established extensive control measures. The demands for reliable, simple, sensitive, rapid and low-cost methods for residue analysis of foods are increasing nowadays. In this study, we established a rapid prediction test for the detection of cattle with violative tissue residues of sulfamethazine. The recommended therapeutic dose of sulfamethazine (withdrawal time, 15 days) was administered to each of 10 cattle. Blood was sampled before drug administration and during the withdrawal period. The concentration of sulfamethazine in plasma, determined by a semi-quantitative ELISA, was compared to that of an internal standard (10 ppb). The absorbance ratio of internal standard to sample (B/Bs) was employed as an index to determine whether drug residues in cattle tissues were negative or positive. That is, a B/Bs ratio less than 1 was considered residue positive and if larger than 1 was considered negative. All 10 plasma samples from non-treated cattle showed negative to sulfamethazine. Sulfamethazine was detected in plasmas of treated cattle until Day 7 of withdrawal period. The present study showed that the semi-quantitative ELISA could be easily adapted in predicting residues of sulfamethazine in live cattle.

• 한국환경농학회지
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• 제30권4호
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• pp.432-439
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• 2011

BACKGROUND: An official analytical method was developed to determine etofenprox residues in agricultural commodities using high-performance liquid chromatography (HPLC). METHODS AND RESULTS: The etofenprox residue was extracted with acetone from representative samples of five raw products which comprised rice grain, apple, mandarin, cabbage, and soybean. The extract was then serially purified by liquid-liquid partition and Florisil column chromatography. For rice and soybean samples, acetonitrile/n-hexane partition was additionally coupled to remove nonpolar lipids. Reversed phase HPLC using an octadecylsilyl column was successfully applied to separate etofenprox from co-extractives. Intact etofenprox was sensitively detected by ultraviolet absorption at 225 nm. Recovery experiment at the quantitation limit validated that the proposed method could apparently determine the etofenprox residue at 0.02 mg/kg. Mean recoveries from five crop samples fortified at three levels in triplicate were in the range of 93.6~106.4%. Relative standard deviations of the analytical method were all less than 10%, irrespective of crop types. A selected-ion monitoring LC/mass spectrometry with positive atmospheric-pressure chemical ionization was also provided to confirm the suspected residue. CONCLUSION(s): The proposed method is simple, rapid and sensitive enough to be employed in routine inspection or monitoring of agricultural products for the etofenprox residue.

• 한국축산식품학회지
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• 제43권5호
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• pp.914-937
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• 2023

The objective of this study was to establish a multi-residue quantitative method for the analysis of anthelmintic and antiprotozoal drugs in various livestock products (beef, pork, and chicken) using ultra-high-performance liquid chromatography-tandem mass spectrometry. Each compound performed validation at three different levels i.e., 0.5, 1, and 2× the maximum residue limit according to the CODEX guidelines (CAC/GL 71-2009). This study was conducted according to the modified quick, easy, cheap, effective, rugged, and safe procedure. The matrix-matched calibrations gave correlation coefficients >0.98, and the obtained recoveries were in the range of 60.2%-119.9%, with coefficients of variation ≤32.0%. Furthermore, the detection and quantification limits of the method were in the ranges of 0.03-3.2 and 0.1-9.7 ㎍/kg, respectively. Moreover, a survey of residual anthelmintic and antiprotozoal drugs was also carried out in 30 samples of beef, pork, and chicken collected in Korea. Toltrazuril sulfone was detected in all three samples. Thus, our results indicated that the developed method is suitable for determining the anthelmintic and antiprotozoal drug contents in livestock products.

• Mass Spectrometry Letters
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• 제10권2호
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• pp.43-49
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• 2019

The aim of this study was conducted to develop an analytical method to determine the concentration of ceftiofur residue in eel, flatfish, and shrimp. For derivatization and extraction, the sample was hydrolyzed with dithioerythritol to produce desfuroylceftiofur, which was then derivatized by iodoacetamide to obtain desfuroylceftiofur acetamide. For purification, the process of solid phase extraction (Oasis HLB) was used. The target analytes were confirmed and quantified in $C_{18}$ column using liquid chromatography-tandem mass spectrometry with 0.1% formic acid in water (A) and 0.1% formic acid in acetonitrile (B) as the mobile phase. The linearity of the standard calibration curve was confirmed by a correlation coefficient, $r^2>0.99$. The limit of quantification for ceftiofur was 0.002 mg/kg; the accuracy (expressed as the average recoveries) was 80.6-105%; the precision (expressed as the coefficient of variation) was below 6.3% at 0.015, 0.03, and 0.06 mg/kg. The validated method demonstrated high accuracy and acceptable sensitivity to meet the Codex guideline requirements. The developed method was tested using market samples. As a results, ceftiofur was detected in one sample. Therefore, it can be applied to the analysis of ceftiofur residues in fishery products.

• 한국환경농학회지
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• 제36권3호
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• pp.184-192
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• 2017

BACKGROUND: This study was performed to evaluate the residue dissipation of boscalid and spinetoram on crown daisy and sweet pepper affected by the morphology of the crop. The half-lives and dissipation rate constants for boscalid and spinetoram on crown daisy and sweet pepper were calculated. And then lower limit of 95% confidence interval for dissipation rate constant could be used to propose the pre-harvest residue limit. METHODS AND RESULTS: The pesticide products diluted according to the pesticide label were applied one time on crown daisy and sweet pepper at 2 field sites, respectively. Initial concentration of boscalid and spinetoram on crown daisy after application were in the range of 72.80~117.15 mg/kg and 2.82~4.67 mg/kg, respectively. And Initial concentration of boscalid and spinetoram on sweet pepper were in the range of 1.58~1.62 mg/kg and 0.10~0.21 mg/kg, respectively. Boscalid and spinetoram for crown daisy dissipted below the maximum residue limit(MRL) at 10 and 2 days after application, respectively. All residues concentration of boscalid and spinetoram for sweet pepper below the MRL at 0 day after application. The half-lives based on dissipation rate constant for boscalid and spinetoram on crown daisy were 4.2~4.9 days and 3.0~2.4 days respectively. And the half-lives for boscalid and spinetoram on sweet pepper were 6.7~7.0 days and 2.8~4.0 days respectively. CONCLUSION: The difference in initial concentration of boscalid and spinetoram among crop commodities were due to different crop morphology with larger surface areas. This study was suggested that pre-harvest residue limit would be calculated from lower limit of 95% confidence interval for dissipation rate constant and would be useful to protect consumers by controlling the pesticide residues in crop.

• 분석과학
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• 제28권3호
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• pp.175-181
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• 2015

Cyantraniliprole은 DuPont사에서 개발한 anthranilic diamide계 살충제로 나비목 팔랑나비과(Lepidopera), 딱정벌레목(Coleoptera), 파리목(Diptera)과 흰개미목(Isoptera)과 같은 해충에 효과가 뛰어나다. 국내의 경우 고추, 대파, 복숭아, 사과, 피망 등 15 품목에 잔류허용기준(0.2~2.0 mg/kg)이 설정되어 있어, 본 연구에서는 대파 중에 잔류할 수 있는 cyantraniliprole의 잔류분석시험법을 HPLC-VUD를 이용하여 개발하고자 하였다. Allium속에 포함되는 조미채소인 대파는 함유황 유기화합물을 가지고 있는 대표식물로 이를 제거하기 위한 전처리법 개발이 아주 중요하다. 이를 위해 함유황 유기화합물을 생성하는 allinase 효소를 불활성화시키기 위해 pH 10의 염기상태로 만들어서 효소의 활성을 감소시켜 황화합물의 생성을 감소시켰다. 확립된 시험법 검증을 위해 회수율을 측정한 결과 본 시험법의 회수율은 81.9~83.2%로 나타났으며, 분석오차는 10% 미만으로 코덱스가이드라인에 적합하였다. Cyantraniliprole의 정량한계는 0.05 mg/kg이었으며, 추가적으로 LC-MS를 통한 재확인 과정을 확립하였다. 활용될수 있다고 생각된다.

• EDISON SW 활용 경진대회 논문집
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• 제5회(2016년)
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• pp.90-95
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• 2016

Heat Shock 70kDa Protein 1-Like(HSPA1L)는 Heat-shock protein70(HSP70) family에 속하는 chaperone protein으로 polypeptide folding, assembly, protein degradation 등 다양한 biological processes에 관여하고 있다. HSPA1L은 human methyltransferase-like protein 21A(METTL21A)에 의해 lysine residue에 methylation이 일어나게 되는데, 암세포에서 일반적인 HSPA1L은 주로 세포질에서 발견되는 반면 methylated HSPA1L의 경우 주로 핵에서 발견이 됨으로써 HSPA1L methylation이 암 세포 성장에 중요할 역할을 할 것이라 추측되며 anti-cancer drug target으로 주목 받고 있다. 하지만 현재 HSPA1L의 구조가 부분적으로만 밝혀져 있어 HSPA1L와 METTL21A가 어떤 residue들이 interaction 하여 binding을 하는지에 대해서 아직 밝혀 지지 않았다. 이로 인해 anti-cancer drug target으로서의 연구에 제한이 있다. 이번 연구에서는 homology modeling(Galaxy-TBM, Galaxy-refine)을 통해 HSPA1L 전체 구조를 밝혀 낸 후, HSPA1L 와 METTL21A를 protein-protein docking을 통해 binding pose 예측을 하였다. 이러한 binding pose를 protein interaction analysis하여 HSPA1L과 METTL21A binding에 관여하는 중요 residue들을 밝혀 냈다. 이러한 structural information은 methylated HSPA1L와 암 세포 성장간의 연관성, 더 나아가 anti-cancer drug 개발로 까지도 이어 질 수 있을 것이라 생각한다.

• 한국환경농학회지
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• 제30권1호
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• pp.89-97
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• 2011

축산물 중 cypermethrin 잔류를 예로 농약 및 농물용의 약품으로 사용되는 약제와 이성질체를 포함한 약제에 대한 잔류허용기준 설정의 문제점과 개선사항을 실험과 문헌을 통해 검토하였다. 과학적이고 합리적인 잔류허용기준설정을 위해서는 분석 대상 시료 및 적용부위의 명확성과 합의된 정의의 도출 그리고, 분석 대상화합물의 명확한 지정이 있어야 한다. 그리고 이를 바탕으로 규제 검사, 연구목적의 모니터링, 관련 분석법 개발 등이 보다 깊은 연관성을 가질수 있도록 관련 전문가들의 관심과 합의점 도출은 매우 중요하다.

• 한국환경농학회지
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• 제34권2호
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• pp.111-119
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• 2015

BACKGROUND: Ethychlozate (ECZ) is a plant growth regulator of synthetic auxin for agricultural commodities (ACs). Accurate and sensitive method to determine ECZ in diverse ACs on global official purpose is required to legal residue regulation. As the current official method is confined to the limited type of crops with poor validation, this study was conducted to improve and extend the ECZ method using high-performance liquid chromatography (HPLC) in all the registered crops with method verification. METHODS AND RESULTS: ECZ and its acidic metabolite (ECZA) were both extracted from acidified samples with acetone and briefly purified by dichloromethane partition. ECZ was hydrolyzed to form ECZA and the combined ECZA was finally purified by ion-associated partition including hexane-washing. The instrumental quantitation was performed using HPLC/ FLD under ion-suppression of ECZA with no interference by sample co-extractives. The average recoveries of intra- and inter-day experiment ranged from 82.0 to 105.2% and 81.7 to 102.8%, respectively. The repeatability and reproducibility for intra- and inter-day measurements expressed as a relative standard deviation was less than 8.7% and 7.4%, respectively. CONCLUSION: Established analytical method for ECZ residue in ACs was applicable to the nation-wide pesticide residues monitoring program with the acceptable level of sensitivity, repeatability and reproducibility.

• 한국환경농학회:학술대회논문집
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• 한국환경농학회 2011년도 30주년 정기총회 및 국제심포지엄
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• pp.469-470
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• 2011