虾中CAP检测方法.doc

FDA/ORA/DFS No. 4290 Page 1 of 18 LC/MS/MS Analysis of Chloramphenicol in Shrimp Barbara K. Neuhaus,* Jeffrey A. Hurlbut* and Walter Hammack**, * Food Drug Administration, Pacific Regional Lab - NW, 22201 23RD Drive SE, Bothell, WA 98021 ** Chemical Residue Lab, FL Dept. of Agriculture Consumer Services, 3125 Conner Blvd., Tallahassee, FL 32399 Abstract Recently our laboratory (FDA, PRL-NW) was given the task of testing the performance of a method developed at the Chemical Residue Lab of the Florida Dept. of Agriculture. This is a liquid chromatographic mass spectrometric (LC/MS/MS) method for qualitative and quantitative detection of chloramphenicol (CAP) in shrimp at the sub parts per billion (ppb) level. Shrimp is pulverized with dry ice, is extracted with ethyl acetate, evaporated with N2, treated with hexane/aqueous NaCl, extracted back into ethyl acetate, dissolved into methanol-water after evaporation, and injected into an LC/MS. CAP eluted from the C18 LC column at about 12.2 min using an acetic acid – ammonium acetate – acetonitrile - water mobile phase. The mass spectrometer was operated in the negative ion mode using selected reaction monitoring, and the precursor ion at m/z = 321 yielded four main product ions of m/z = 257, 194, 176 and 152. The peak area of the m/z 152 peak was used for quantitation. Linear plots were obtained between 0.50 and 10.0 ng/mL CAP. Shrimp tissues were fortified with CAP at 0.10, 0.25, 0.50 and 1.0 ng/mL. Overall recoveries were 85, 92, 85 and 102 % with % RSD values of 9.4, 1.6, 3.1 and 2.5% respectively. The limit of quantitation (LOQ) was 0.3 ng CAP per g of shrimp (0.3 ppb), and the limit of detection (LOD) was estimated to be 0.08 ppb. Note: This Laboratory Information Bulletin (LIB) is a tool for the rapid dissemination of laboratory methods which appear to work. It does not necessarily report completed scientific work. Users must assure themselves by appropriate validation procedure