Portal de Periódicos da CAPES

Artigo Produção Nacional Revisado por pares

BIBTEX RIS

A Conductimetric System Based on Polyaniline for Determination of Ammonia in Fertilizers

1997; Taylor & Francis; Volume: 30; Issue: 12 Linguagem: Inglês

10.1080/00032719708001732

1532-236X

Jane Maria Gonçalves Laranjeira, W.M. de Azevêdo, Mário César Ugulino de Araújo,

Electrochemical sensors and biosensors

Abstract A simple conductimetric system to determine ammonia concentration using a sensor based on a conductor polymer was developed. The sensitive element to ammonia is a thin polyaniline film deposited by chemical synthesis in an acrylic substrate prepared before hand with two graphite electrodes. The conductance of the polyaniline film decreases when exposed to the ammonia gas and this variation can be related to the ammonia concentration. To determine ammonia in fertilizer samples a system consisting of a measurement cell, a conductivity meter and a strip chart recorder was used. The results were compared with those obtained by three different laboratories employing a Kjeldahl method and are in good agreement. The detection range of the system was 0.6 to 3.7 μg.mL−1 with a response time of 4 minutes. The relative standard deviation of the proposed method was about 5%.