Evaluation of the selectivity of molecularly imprinted polymer cartridges for nitroimidazoles. Application to the simultaneous extraction of nitroimidazoles and benzimidazoles from samples of animal origin

In this work the selectivity of commercial molecularly imprinted polymer (MIP) cartridges for nitroimidazoles has been evaluated. For this, a sample treatment based on molecularly imprinted solid phase extraction (MISPE) has been developed and applied to the simultaneous extraction of nitroimidazoles and benzimidazoles. These cartridges were compared with other sorbents commonly used for the solid phase extraction (SPE) of veterinary drugs such as C18, hydrophilic/lipophilic balanced (HLB), and strong cation exchange (SCX). Analysis of the extracts was carried out by HPLC-MS/MS. The use of MIP cartridges provided good results for all nitroimidazoles and for most of the benzimidazoles studied (except for the most apolar analytes), both in terms of recovery and precision and in the cleaning of the extracts. Thus, although MIPs have been designed to specifically bind to a target molecule, i.e., nitroimidazoles, they are able to extract other analytes, such as benzimidazoles, with high efficiency. The developed method was applied to the determination of four nitroimidazoles and ten benzimidazoles in samples of animal origin. All nitroimidazoles and eight of the benzimidazoles were successfully determined. Validation of the method afforded values in the range of 91–111% for the recovery studies. The analysis of intra-day and inter-day precision showed relative standard deviation values lower than 9.5 % and 12 % respectively. These results indicate that the proposed method is suitable for the determination of nitroimidazoles and benzimidazoles in samples of animal origin.