Pervaporation-flow injection determination of ammonia in the presence of surfactants

Abstract

A pervaporation flow-injection method is described for the analysis of ammonia in complex matrices (e.g. in the presence of surfactants, solid particles). The donor solution is 1.0moll-1 NaOH while the acceptor solution contains mixed acid-base indicators cresol red and thymol blue. The color change resulting from the ammonia entering the acceptor stream in the pervaporation unit is monitored photometrically at 590nm. The method is characterized by a linear calibration range between 0.2 and 20mgl-1, sampling frequency of 11h-1 and detection limit of 0.1mgl-1. The presence of surfactants in high concentrations (1000mgl-1) does not affect the analytical determination. The method was applied su..