Determination of polyphosphates in fish and shrimp muscles by capillary electrophoresis with indirect UV detection after phosphatase inhibition using high pressure pretreatment

A method was proposed for the determination of polyphosphates (P2O74−, P3O105− and (PO3)33−) in fish and shrimp muscles by capillary electrophoresis with indirect UV detection after phosphatase inhibition using high pressure pretreatment (HPP). Separation parameters were optimized and the effects of HPP on deactivation of enzyme were investigated. Well resolution was obtained with 10 mM adenosine 5′-phosphate (ATP) in 16 mM disodium hydrogen phosphate combining with 32 mM citric acid buffer (pH = 6.4) containing 0.1 mM cetyltrimethyl ammonium bromide, and phosphatase was effectively inhibited by HPP at 400 MPa for 10 min. Method was validated with LOD (0.23-0.33 mg g−1) and LOQ (0.77-1.0 mg g−1). Recovery of P2O74−, P3O105− and (PO3)33− in the fortified samples were in the range of 91.6-100.1%, 97.6-104.6% and 79.1-88.1%, respectively, and the corresponding RSD ranged from 1.1% to 6.8%. Finally, the method was applied in the determination of polyphosphates in food samples collected from local markets.