A new poly(vinyl chloride) membrane based all solid state electrochemical sensor containing synthesized triazole compound namely 4-(5-bromothiophen-2-carboxylidene amino)-3-methyl-5-mercapto-s-triazole (BTMMT) as an electroactive material was prepared and investigated as a chromium(111) selective sensor. The optimum composition of the best performing membrane contained triazole:NaTPB (sodiumtetraphenylborate):NPOE (nitrophenyl octyl ether):PVC in the ratio 10:2:50:38 (w/w). The sensor exhibited near Nernstian slope of 19.8 +/- 0.2 mV/decade of activity in the working concentration range of 2.0 x 10(-7) to 1.0 x 10(-1) M. It displayed a stable potential response in the pH range 2.2-5.0. The sensor exhibited a fast response time of 10-15 s and could be used for at least three months without any considerable divergence in potentials. The proposed sensor showed very good selectivity over most of the common cations including Li+, K+, Na+, Ni2+, Co2+, Cu2+, Sr2+, Ba2+, Cs+, Pb2+, Zn2+, Mg2+, Cd2+, Fe3+, and La3+. Also, it was successfully used for the determination of Cr(III) activity in the waste from electroplating, and lather tanning industry. (C) 2012 Elsevier Ltd. All rights reserved.