Derivatization strategies for CE-LIF analysis of biomarkers: Toward a clinical diagnostic of familial transthyretin amyloidosis

International audienceWe report three derivatization strategies for CE analysis with LIF detection (CE‐LIF) of two synthetic peptides mimicking the wild and mutated fragments of interest for the diagnosis of familial transthyretin amyloidosis. The precapillary derivatization of the peptides with three optical tags, 5‐carboxytetramethylrhodamin succinimidyl ester (TAMRA‐SE), naphtalene‐2,3‐dicarboxyaldehyde (NDA), and 3‐(2‐furoyl)quinoline‐2‐carboxyaldehyde (FQ) has been investigated by CE‐LIF detection and MS. Results provide evidence that high reaction yields have been reached whereas the multitagging phenomenon has occurred for both NDA and TAMRA‐SE labeling procedures. The derivatization and electrokinetic separation of a mixture of the two peptides of interest for the pathology diagnosis (22‐aa peptides that differ only from one amino acid) were achieved using both approaches. The highest resolution with a value of 2.5 was obtained with TAMRA‐SE labeled derivatives whereas NDA gave the best detection sensitivity (LOD of 2.5 μM). The validation of the developed methods showed a good linearity (R ≥ 0.997) between the peak area of the labeled derivatives and the peptide concentration for both NDA and FQ labeling procedures. The intraday RSDs of A and the migration times were less than 3.8 and 2.2%, respectively