Comparative evaluation of three different ELISA assays and HPLC-ESI-ITMS/MS for the analysis of N-epsilon carboxymethyl lysine in food samples

Abstract

N-epsilon-carboxymethyl-lysine (CML) is measured in food, but there is a controversy concerning the most convenient yet reliable method(s) for this task. This work compares three different ELISA assays and HPLC-ESI-ITMS/MS for the analysis of CML in several food items. The four methods showed the same decreasing order of CML concentration: beef, bacon > chicken > fish > dairy products > grain products > fruits/vegetables. HPLC-ESIITMS/ MS results highly correlated with those obtained by ELISA performed with monoclonal CML-antibody (beta = 0.98, p < 0.0001) whereas My Bio Source (R) kit results were not correlated with those provided by Lamider (R). Small differences of CML concentrations in food items prepared by different culinary treatment were clearly distinguished by HPLC-ESI-ITMS/MS, but could not always be detected by ELISA. This work demonstrates a reasonable relationship between CM determined by ELISA and HPLC-ESI-ITMS/MS and therefore supports the implementation of ELISA in food CML/AGEs screening.