SPECTROPHOTOMETRIC DETERMINATION OF TOTAL PROTEINS BY DERIVATIZATION WITH p-BENZOQUINONE IN A FLOW SYSTEM

Abstract

The determination of total proteins in plasma is largely needed in clinical and biochemical areas because it is important for the diagnosis of several diseases. This paper describes a flow method for determination of total protein in human serum albumin samples using p-benzoquinone (PBQ) dissolved in dimethyl-sulphoxide (DMSO) as reagent. The reactional mixture at pH 8.0 or 9.0 was pumped through a coiled stainless steel capillary tube reactor, heated at 90°C, to a spectrophotometric flow cell where the absorbance was monitored at 361 nm. A linear dynamic range was observed for protein concentrations from 50 to 500 μg mL⁻¹. Results were in good agreement with those obtained by the Kjeldahl's method.

Keywords:

• p-Benzoquinone
• Total proteins
• Derivatization
• Flow system
• Reactor
• Spectrophotometric assay

Acknowledgments