Determination of a major allergen in fish samples by simple and effective label-free capillary electrophoretic analysis after background suppression in ion-exchange chromatography

A simple analytical method using ion-exchange chromatography (IEC) coupled with capillary zone electrophoresis (CZE) was newly developed for detection and quantification of parvalbumin (PV), a major allergen, in fish. The procedure of IEC for simple enrichment of PV crude extract was optimized. By using 25 mmol/L borate-borax buffer with 15 kV separation voltage at pH 9.2 for CZE separation, the migration time, separation efficiency and electrophoretic resolution greatly improved. Under the optimal conditions, PV was determined in 2.8 min, with the limit of detection (LOD) at 0.71 μg/mL (S/N = 3) and the recoveries at 89.6%-104.7%. We also found that only when the concentration of PV was above LOD reported here was the protein capable of stimulating human mast cell degranulation, indicating the biological significance of the LOD. Finally, the use of this method to analyze fish samples with simple sample preparation highlights the applicability for detection of allergens in seafood matrices.