Value Assignment to Six Selected Nitroimidazoles in a Candidate Reference Material

5-Nitroimidazoles were used in the past as efficient veterinary drugs for the treatment of bacterial infections (coccidiosis, haemorrhagic enteritis) in pigs and poultry, but are meanwhile banned in the EU due to possible adverse health effects. To ensure effective consumer protection, reliable analytical methods need to be developed and validated. Certified Reference Materials (CRMs) are a key element towards reliable measurement results and are typically used for method validation (e.g. trueness control) and method performance verification. IRMM currently established a CRM for 6 selected nitroimidazole compounds in an incurred pork meat matrix. One key part in a certification project is the laboratory inter-comparison aiming at assigning values to the analytical entities in the material. 12 European Laboratories participated in this exercise, all provided with a lyophilised blank material, some units of the candidate CRM, and a common calibrant prepared at IRMM. They were requested to identify and quantify dimetridazole (DMZ), metronidazole (MNZ), ronidazole (RNZ), hydroxy ipronidazole (IPZOH), hydroxy metronidazole (MNZOH), and the commn hydroxy metabolite of RNZ and DMZ, 2-hydroxymethyl-1-methyl-5-nitroimidazole (HMMNI) in the incurred candidate reference material by using their validated methods, and complying with the protocol dispatched with the samples (instruction of handling of samples and calibrants, use of QC samples in the measurement series, reporting instructions). Each lab was requested to submit results from 8 independent measurements spread over 2 days (within-laboratory reproducibility conditions). Five analytes could be quantified, and concentrations in the low µg/kg range were reported. In addition, the concentration for one analyte fell below LOD (CCa) in all laboratories. Standard deviations of the mean values were between 5 and 16 RSD %. Within-laboratory results variation typically ranged from 3 to 15 RSD %. Seen the different sample extraction and clean-up procedures and the variation in the measurement methods (HPLC conditions, ionisation techniques, MS settings), comparability of results at an acceptable level was obtained for these analytically demanding compounds present in a complex food matrix at low (sub) ppb levels.

ZELENY Reinhard;  HARBECK Stefan;  SCHIMMEL Heinz; 

2010-09-07

Euroresidue

JRC43538

https://publications.jrc.ec.europa.eu/repository/handle/JRC43538,