Spectrophotometric determination of histamine in mast cells, muscle and urine by solvent extraction with copper(II) and tetrabromophenolphthalein ethyl ester.

Abstract

A simple and sensitive method for the determination of histamine in mast cells, rat muscle and urine using solvent extraction and spectrophotometry is described. The method is based on the formation of a Cu(II) histamine chelate cation, followed by extraction of the ion associate with tetrabromophenolphthalein ethyl ester into 1,2-dichloroethane and measurement of the absorbance of the complex to determine histamine. Low levels (0.2 µg ml–1) of histamine in rat mast cells, rat muscle and urine can be directly determined without purification from other derivatives and biogenic amines. A linear calibration graph is obtained in the concentration range 1 × 10–6–5 × 10–6M(0.2–1 µg ml–1) of histamine in aqueous solution. The molar absorptivity is 3.4 × 104 l mol–1 cm–1 at 515 nm. The precision of the method is ±2.5%.