本研究旨在開發簡單、快速、靈敏度高之檢測方法,以監測水牛肉中羥四環黴素(OTC)、四環黴素(TC)及氯四環黴素(CTC)之殘留量。此方法主要包括McIIvaine緩衝溶液(pH 3.85)萃取及固相淨化等步驟。HPLC部分,使用逆向C8(RP-C8)管柱,移動相為0.01 M草酸緩衝溶液(pH 1.6)/乙腈/甲醇(77:18:5,v/v/v),流速為0.6 mL/min,溫度為35°C。光二極體列陣檢出器之波長設定為355 nm。本方法的檢測極限為0.031 μg/g,最低定量極限為0.062 μg/g。外添加三種濃度之OTC、TC及CTC回收率,經統計評估後均高於78%。添加0.062 μg/g時,同日內及異日間之變異係數分別不超過11.4%及14.5%,顯示此方法有良好的重覆性及再現性。本方法亦同時應用於印度不同地區122件出口水牛肉之監測,其中僅5件驗出OTC殘留,但均低於聯合國食品標準委員會(CAC)、歐盟(EU)及美國食品暨藥物管理局(FDA)所訂之最高殘餘限量(MRLs);TC及CTC則均未檢出。
The development of a simple, rapid and sensitive method for residue monitoring of oxytetracycline (OTC), tetracycline (TC) and chlortetracycline (CTC) in buffalo meat samples is described. The principal steps involved extraction in McIIvaine buffer (pH 3.85) followed by a solid phase clean up step. In HPLC, a reversed phase C8 (RP-C8) column was used and compounds were separated at 35℃ using a mobile phase of 0.01 M oxalic acid buffer (pH 1.6)/acetonitrile/methanol (77:18:5, v/v/v) at a flow rate of 0.6 mL/min. A wavelength of PDA detector was set at 355 nm. The detection limit of the method was calculated to be 0.031 μg/g and the minimum detectable quantity was found to be 0.062 μg/g. The statistical evaluation demonstrated high absolute recoveries of OTC, TC and CTC from spiked samples at three fortification levels, which were higher than 78% for all drugs. Excellent method repeatability and reproducibility was found by intra- and inter-day assay precision, yielding the coefficients of variation not more than 11.4 and 14.5% at 0.062 μg/g spike concentrations, respectively. The method was also employed for monitoring of 122 export buffalo meat samples collected from different parts of India, in which only 5 samples showed detectable concentration of OTC residues but were lower than the maximum residue limits (MRLs) set by Codex Alimentarius Commission (CAC), European Union (EU), and United States Food and Drug Administration (US-FDA). TC and CTC were absent in all samples.