Isotope dilution ESI-LC-MS/MS for quantification of free and total Nε-(1-Carboxymethyl)-l-Lysine and free Nε-(1-Carboxyethyl)-l-Lysine: Comparison of total Nε-(1-Carboxymethyl)-l-Lysine levels measured with new method to ELISA assay in gruel samples.
ESI-LC-MS/MS method with isotope dilution and SPE based on cation-exchange was developed for determination of free and total Nε-(1-Carboxymethyl)-l-Lysine (CML) and free Nε-(1-Carboxyethyl)-l-Lysine (CEL). The use of nonafluoropentanoic acid in mobile phase was omitted, SPE recoveries of 82±3% and 91±10% (n=6) for CML and CEL respectively and, calibration curves (R(2)>0.9985) were attained. The me
