Flow injection analysis of picric acid explosive using a copper electrode as electrochemical detector

A simple and fast electrochemical method for quantitative analysis of picric acid explosive (nitro-explosive) based on its electrochemical reduction at copper surfaces is reported. To achieve a higher sample throughput, the electrochemical sensor was adapted in a flow injection system. Under optimal experimental conditions, the peak current response increases linearly with picric acid concentration over the range of 20–300μmolL−1. The repeatability of the electrode response in the flow injection analysis (FIA) configuration was evaluated as 3% (n=10), and the detection limit of the method was estimated to be 6.0μmolL−1 (S/N=3). The sample throughput under optimised conditions was estimated to be 550 samplesh−1. Peroxide explosives like triacetone triperoxide (TATP) and hexamethylene triperoxide diamine (HMTD) were tested as potential interfering substances for the proposed method, and no significant interference by these explosives was noticed. The proposed method has interesting analytical parameters, environmental applications, and low cost compared with other electroanalytical methods that have been reported for the quantification of picric acid. Additionally, the possibility to develop an in situ device for the detection of picric acid using a disposable sensor was evaluated. [Display omitted] ► A fast and low-cost electrochemical method for analysis of picric acid is reported. ► The electrochemical sensor was adapted in a flow injection system. ► High sample throughput, good detection limit and repeatability were obtained. ► Possibility to use a disposable sensor for the detection of explosive in situ. ► Interference by other nitrocompounds could be solved by a chemometric tool.