Detection of Attomolar Concentrations of Alkaline Phosphatase by Capillary Electrophoresis Using Laser-Induced Fluorescence Detection

Abstract

Alkaline phosphatase can be assayed by monitoring the conversion of the fluorogenic substrate AttoPhos into the highly fluorescent product AttoFluor. We have used capillary electrophoresis with laser-induced fluorescence detection to monitor this reaction. The concentration limit of detection (3σ) of alkaline phosphatase is 1.5 × 10-17 M (2.1 fg/mL), which corresponds to a mass limit of detection of nine molecules (1.5 × 10-23 mol) contained within a 1-μL sample volume.