In this paper, a sensitive graphite/poly(methyl methacrylate) (PMMA) composite electrode was firstly applied to the determination of o-sec-butylphenol (osBP). This polymer carbon paste electrode (CPE) effectively improved the soft surface of traditional CPE, and enhanced the sensitivity and reproducibility. Factors influencing detection processes were optimized and kinetic parameters were calculated. Under the optimal conditions, the amperometric current density was linear with the concentration of osBP in the range from 2.50 x 10(-7) to 3.55 x 10(-5) mol L-1 and the detection limit was 3.48 x 10(-5) mol L-1. The proposed method was successfully used to determine osBP in greengrocery samples and satisfactory results were obtained. (C) 2012 Elsevier Ltd. All rights reserved.