LC-MS/MS for the simultaneous determination of polar endogenous ADMA and CML in plasma and urine from diabetics

Background: Asymmetric dimethylarginine (ADMA) and ε-N-carboxymethyl-l-lysine (CML) are microvascular risk factors and potential biomarkers of diabetic microvascular complication. Results: Sample preparation was achieved using acetonitrile for protein precipitation step. ADMA, CML and IS CML-d2 were separated with gradient on a Welch Ultimate® XB- NH2 column. The assays were validated according to current bioanalytical guidelines with respect to specificity, linearity (20–1000 ng/ml for ADMA in human plasma, 50–2000 ng/ml in urine, 10–500 ng/ml for CML in human plasma and urine), accuracy and precision, extraction recovery, matrix effect and stability. Conclusion: The LC–MS/MS method was successfully applied to quantification of ADMA and...