Pfenning A P, Roybal J E, Rupp H S, Turnipseed S B, Gonzales S A, Hurlbut J A
U.S. Food and Drug Administration, Denver Federal Center, CO 80225-0087, USA.
J AOAC Int. 2000 Jan-Feb;83(1):26-30.
A gas chromatographic (GC) method is presented for determining residues of chloramphenicol (CAP), florfenicol (FF), florfenicol amine (FFa), and thiamphenicol (TAP) in shrimp tissues, with meta-nitrochloramphenicol (mCAP) as the internal standard. The composited shrimp is extracted with basic ethyl acetate, followed by an acetonitrile-basic ethyl acetate mixture. This extract is centrifuged, filtered, evaporated, and reconstituted in water; the reconstituted extract is acidified, defatted with hexane, and passed through a propylsulfonic acid (PRS) and C18 solid-phase extraction (SPE) system. The C18 SPE column is eluted with methanol, and the PRS SPE column is eluted with basic MeOH plus counter ion. The combined eluates are evaporated, reconstituted in acetonitrile, and derivatized with Sylon BFT. After derivatization, the addition of toluene directly to the sample, followed by the addition of basic water, quenches the derivatization process. After centrifugation, the organic layer is carefully removed, and the analytes are determined by GC with electron capture detection. Shrimp tissues were fortified with fenicols (i.e., CAP, FF, FFa, and TAP) at 5, 10, 20, 40, and 80 ng/mL. Overall recoveries were 88, 101, 91, and 84% with overall interassay (between-day) variabilities (i.e., relative standard deviations) of 5.3, 9.4, 12.8, and 7.4% for CAP, FF, FFa, and TAP, respectively. The method detection limits were calculated as 0.7, 1.4, 2.4, and 1.3 ng/g (ppb) for CAP, FF, FFa, and TAP, respectively, based on a 10 g sample. The quantitation limit as determined empirically by this method is the lower limit of the standard curve, which is about 5 ng/g (ppb) for each analyte.
本文介绍了一种气相色谱（GC）法，用于测定虾组织中氯霉素（CAP）、氟苯尼考（FF）、氟苯尼考胺（FFa）和甲砜霉素（TAP）的残留量，以内标间硝基氯霉素（mCAP）进行测定。将混合虾样先用碱性乙酸乙酯提取，然后用乙腈 - 碱性乙酸乙酯混合物提取。该提取物经离心、过滤、蒸发，再用水复溶；复溶后的提取物酸化后用己烷脱脂，然后通过丙磺酸（PRS）和C18固相萃取（SPE）系统。C18 SPE柱用甲醇洗脱，PRS SPE柱用碱性甲醇加抗衡离子洗脱。合并洗脱液蒸发后，用乙腈复溶，并用Sylon BFT衍生化。衍生化后，直接向样品中加入甲苯，然后加入碱性水，终止衍生化过程。离心后，小心去除有机层，通过带有电子捕获检测的气相色谱法测定分析物。在虾组织中添加浓度为5、10、20、40和80 ng/mL的氟苯尼考类药物（即CAP、FF、FFa和TAP）。CAP、FF、FFa和TAP的总回收率分别为88%、101%、91%和84%，批间（日间）总变异系数（即相对标准偏差）分别为5.3%、9.4%、12.8%和7.4%。基于10 g样品，该方法对CAP、FF、FFa和TAP的检测限分别计算为0.7、1.4、2.4和1.3 ng/g（ppb）。通过该方法经验性确定的定量限是标准曲线的下限，每种分析物约为5 ng/g（ppb）。
