Determination of Nitroimidazoles Drug Residues in Meat Products by HPLC-APCI（+）-MS/MS

An HPLC-APCI（+）MS-MS methodology was developed coupled with solid phase extraction decontamination for the residue determination of nitroimidazoles: metronidazole(MNZ), dimetridazole(DMZ), tindazole(TNZ), ronidazole(RNZ), ternidazole(TerNDZ), ipronidazole(IPZ), hydroxy-metronidazole(MNZOH), hydroxyipronidazole(IPZOH), 2-hydroxymethyl-1-methyl-5-nitro-imidazole(HMMNI). The sample was extracted with the acetonitrile followed by appending deuterium-marker(HMMNI-D³, IPZ-OH-D³)internal standard, and operated for decontamination by OASIS MCX C₁₈ cartridges. The chromatographic column was Superiorex ODS C₁₈, the mobile phase was gradient solvent programming elution, which was consisted of water-acetic acid(0.1%) and acetonitrile-acetic acid(0.1%). Samples were ionized in flowing with a APCI ion source in positive mode， and were detected with MRM mode. The LOQ (S/N＞10) of nitroimidazoles residues in meat sample is 0.5 μg•kg^-1. The response for nitroimidazoles is linear in the range of 0.5-100.0 μg•L^-1, and the correlation coefficient is excellent(r: 0.997 1-0.999 6).