Spectrophotometric Flow Injection Analysis of Protein in Urine Using Tetrabromophenolphthalein Ethyl Ester and Triton X-100

Original Paper

Abstract

A sensitive, rapid and accurate determination of protein in patient urine was carried out by flow injection analysis (FIA) using tetrabromophenolphthalein ethyl ester (TBPE·H) and Triton X-100 at pH 3.0. The detection system was based on the ion association formation between human serum albumin (HSA) and TBPE·H in the micelle formed by Triton X-100. The calibration graph was linear in the range of 0.15 – 12 mg/dL HSA with R² = 0.998. The 3σ limit of detection of the proposed FIA method was 0.05 mg/dL at 610 nm. The relative standard deviation (n = 10) of 3.0 mg/dL HSA was 1.2% and the sample throughput was 30 h^-1.