UPLC-MS/MS method for quantitative determination of the advanced glycation endproducts Nε-(carboxymethyl)lysine and Nε-(carboxyethyl)lysine

During blood storage, red blood cells (RBCs) undergo physical, chemical, and metabolic changes that may contribute to post-transfusion complications. Due to the hyperglycemic environment of typical solutions used for RBC storage, the formation of advanced glycation endproducts (AGEs) on the stored RBCs has been implicated as a detrimental chemical change during storage. Unfortunately, there are limited studies involving quantitative determination and differentiation of carboxymethyl-lysine (CML) and carboxyethyl-lysine (CEL), two commonly formed AGEs, and no reported studies comparing these AGEs in experimental storage solutions. In this study, CML and CEL were identified and quantified on freshly drawn blood samples in two types of storage solutions, standard additive solution 1 (AS-1) and a normoglycemic version of AS-1 (AS-1N). To facilitate detection of the AGEs, a novel method was developed to reliably extract AGEs from RBCs, provide Food and Drug Administration (FDA) bioanalytical guidance criteria, and enable acceptable selectivity for these analytes. Ultra-performance liquid chromatography with tandem mass spectrometry (UPLC-MS/MS) was utilized to identify and quantify the AGEs. Results show this method is accurate, precise, has minimal interferences or matrix effects, and overcomes the issue of detecting AGE byproducts. Importantly, AGEs can be detected and quantified in both types of blood storage solutions (AS-1 and AS-1N), thereby enabling long-term (6 weeks) blood storage related studies.