Validated method for determination of eight banned nitroimidazole residues in natural casings by LC/MS/MS with solid-phase extraction.
A sensitive method based on solid-phase extraction-liquid chromatography-tandem mass spectrometry interfaced with electrospray ionization (SPE-LC-MS/MS-ESI) was developed for the simultaneous determination of 8 banned nitroimidazole (NOZ) drugs including metronidazole (MNZ), ronidazole (RNZ), dimetridazole (DMZ), tinidazole, ornidazole, secnidazole, metronidazole-OH (MNZOH, the metabolite of MNZ), and 2-hydroxymethyl-1-methyl-5-nitroimidazole (HMMNI, the metabolite of RNZ and DMZ) in natural casings. After extraction with ethyl acetate and evaporation, the NOZs were reconstituted in ethyl acetate and purified on a strong cation-exchange SPE column, and then LC/MS/MS analysis was performed by positive ESI applying multiple reaction monitoring of 2 transition reactions for each compound. The method was validated according to the European Union requirements (Commission Decision 2002/657/EC). Specificity, linearity, decision limit (CCalpha), detection capability (CCbeta), accuracy, and precision were determined. Average recoveries of the 8 NOZs from natural animal casing fortified at 3 levels (0.1, 0.5, and 1 microg/kg) ranged from 87.3 to 116.5%. The calculated CCalpha for NOZs ranged from 0.029 to 0.049 microg/kg, and CCbeta ranged from 0.049 to 0.083 microg/kg. Repeatability was in the range of 3.35-10.1%, and within-laboratory reproducibility was <10.3%.
Sun
Hanwen
H
Hebei University, College of Chemistry and Environmental Science, Key Laboratory of Analytical Science and Technology of Hebei Province, Baoding, 071002, People's Republic of China. hanwenhbu@yahoo.com.cn
Wang
Fengchi
F
Ai
Lianfeng
L
Guo
Chunhai
C
Chen
Ruichun
R
D000818:Animals; D000981:Antiprotozoal Agents / Q000032:analysis; D002681:China; D002853:Chromatography, Liquid / Q000379:methods* / Q000706:statistics & numerical data; D005506:Food Contamination / Q000032:analysis* / Q000706:statistics & numerical data; D007422:Intestines / Q000737:chemistry; D008461:Meat Products / Q000032:analysis; D009593:Nitroimidazoles / Q000032:analysis*; D052616:Solid Phase Extraction / Q000379:methods* / Q000706:statistics & numerical data; D053719:Tandem Mass Spectrometry / Q000379:methods* / Q000706:statistics & numerical data
D000981:Antiprotozoal Agents; D009593:Nitroimidazoles