• Analytical Science and Technology
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• v.23 no.5
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• pp.437-445
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• 2010

The aim of this study was to develop an analytical method for sulfonamide antibiotics (sulfadiazine, sulfamerazine, sulfamethazine, sulfamethoxazole, sulfathiazole) and their metabolites ($N^4$-acetylsulfadiazine, $N^4$-acetylsulfamerazine, $N^4$-acetylsulfamethazine, $N^4$-acetylsulfamethoxazole, sulfamethoxazole-$N^1$-glucuronide) in environmental samples. The solid phase extraction (SPE) with LC/ESI-MS/MS have been used for the analysis of target compounds, and the recoveries of SPE clean-up were at the range of 12-94% for C18 cartridge, 60-95% for HLB cartridge, 25-123% for MCX cartridge, and 70-90% for tandem HLB/MCX. By established method, detection limit, recovery, and relative standard deviation were 0.001~0.187 ng/mL, 66~115%, and 5~17%, respectively. This method was effective and sensitive to use for the simultaneous determination of sulfonamide antibiotics and their metabolites in environmental samples. Four sulfonamide antibiotics were detected at the range of 0.008~2.153 ng/mL. For metabolites, only $N^4$-acetylsulfamethoxazole was detected, but the concentration was under the MDL level.

• Korean Journal of Food Science and Technology
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• v.42 no.5
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• pp.515-520
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• 2010

This research investigated benzimidazole residues (albendazole, fenbendazole, flubendazole, thiabendazole, oxibendazole) in livestock products. A total of 270 samples of livestock products (beef, pork and chicken) were purchased from local markets in Korea. Ethyl acetate was used to extract analytes from the sample, after which ethyl acetate extracts were purified using a MCX cartridge. Analytes were detected using liquid chromatography-tandem mass spectrometry. The limit of detection was 0.01-0.04 ppb, the limit of quantification was 0.03-0.13 ppb, the linearity ($r^2$) was 0.9992-1.0000, and the recovery was 70-85%. Residues of benzimidazoles, except for fenbendazole in pork, were not found in any of the 270 livestock samples. Fenbendazole was detected in the range of 1.2 to 3.1 ppb in 12 samples of pork.

• Bulletin of the Korean Chemical Society
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• v.28 no.5
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• pp.737-744
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• 2007

An isotope dilution-liquid chromatography/tandem mass spectrometric method was developed as a candidate reference method for the accurate determination of acrylamide in potato chips, starch-rich foodstuff cooked at high temperature. Sample was spiked with 13C3-acrylamide and then extracted with water. The extract was further cleaned up with an Oasis HLB solid-phase extraction (SPE) cartridge and an Oasis mixed-phase cation exchange (MCX) SPE cartridge. The extract was analyzed by using LC/ESI/Tandem MS in positive ion mode. LC with a medium reversed-phase (C4) column was optimized to obtain adequate chromatographic retention and separation of acrylamide. MS was operated to selectively monitor [M+H]+ ions of the analyte and its isotope analogue at m/z 72 and m/z 75, respectively. Sample was also analyzed by the LC/MS with selectively monitoring the collisionally induced dissociation channels of m/z 72 → m/z 55 and m/z 75 → 58. Compared to the LC/MS chromatograms, the LC/MS/MS chromatograms showed substantially reduced background chemical noises coming from solvent clusters formed during ESI spray processes and interferences from sample matrix. Repeatability and reproducibility studies showed that the LC/MS/MS method is a reliable and reproducible method which can provide a typical method precision of 1.0% while the LC/MS results are influenced by chemical interferences.

• Journal of Korean Society on Water Environment
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• v.32 no.6
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• pp.628-648
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• 2016

Increased attention has been paid to the presence of veterinary antibiotics in various environmental matrices due to their toxicological behavior in the ecosystem and development of antibiotic-resistant strains of pathogenic bacteria. In the this review, 37 target antimicrobials were selected based on annual sales of antibiotics for livestock in South Korea 2014. Also, extraction and clean-up methods for the determination of the antibiotic residues in liquid samples including water, milk, and honey were comprehensively reviewed in the literature. Solid-phase extraction (SPE) was commonly used as a pre-treatment method for the samples. Most of the analytes were extracted in acidic conditions (2.5~4.0) except for aminoglycosides, which were extracted in neutral conditions (7.0~8.0). ${\beta}-Lactams$ showed the highest recoveries in neutral pH due to their degradation characteristics in acidic media. Starta-X, Oasis HLB, and Oasis MCX were frequently applied as an SPE cartridge and Oasis HLB showed the highest recoveries for the majority of antibiotic classes. The homogenized honey and milk were extracted by mixing with acids for deproteinization. Solids and other interfering substances in the extract were eliminated by centrifugation followed by membrane filtration or SPE before injection into HPLC.

• Korean Journal of Environmental Agriculture
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• v.32 no.1
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• pp.70-77
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• 2013

BACKGROUND: Nitroxoline is an antibiotic agent. It is used for the treatment of the second bacterial infection by the colibacillosis, salmonellosis and viral disease of the poultry. When the nitroxoline is indiscreetly used, the problem about the abuse of the antibiotics can occur. Therefore, this study presented the residue analytical method of nitroxoline in food for the safety management of animal farming products. METHODS AND RESULTS: A simple, sensitive and specific method for nitroxoline in chicken muscle by high performance liquid chromatograph with PDA was developed. Sample extraction with acetonitrile, purification with SPE cartridge (MCX) were applied, then quantitation by HPLC with C18 column under the gradient condition with 0.1 % tetrabutylammonium hydroxide-phosphoric acid and methanol was performed. Standard calibration curve presented linearity with the correlation coefficient ($r^2$) > 0.999, analysed from 0.02 to 0.5 mg/L concentration. Limit of quantitation in chicken muscle showed 0.02 mg/kg, and average recoveries ranged from 72.9 to 88.1 % in chicken muscle. The repeatability of measurements expressed as coefficient of variation (CV %) was less than 12 % in 0.02 and 0.04 mg/kg. CONCLUSION(S): Newly developed method for nitroxoline in chicken muscle was applicable to food inspection with the acceptable level of sensitivity, repeatability and reproducibility.