Determination of plant available boron in agricultural soil by using voltammetric method

In this study, a novel voltammetric method has been developed to determine the amount of boron in soil. 50 soil samples were collected from 5 typical sites of agricultural area. After hot water extraction of available boron in the soil samples, all boron is complexed by addition of Alizarin Red S (ARS) to the extraction solutions.Differential pulse anodic stripping voltammetry was used to determine the amount of the boron complexes. The electrochemical parameters have been optimized according to the experimental results. The optimum scan rate, stirring rate, deposition potential, deposition time and pH values were determined as 5 mVs -1 , 200 rpm, -0.5 V (vs. Ag/AgCl, sat.), 15sec. and 7.5, respectively. An oxidation peak was occurred at the peak potential of -0.45 V for Boron-Alizarin complex. The limit of detection, limit of quantification and linear working range were determined for the voltammetric soil-boron analysis. In addition, the interference effects of coexisting ions were successfully investigated. Comparison of the analytical data for analyzing real samples was carried out between the differential pulse anodic stripping voltammetric method and the Azometine H spectrophotometric method have shown good agreement. A great advantage of voltammetry over the spectrophotometric method is found to be simplicity, selectivity and shortening of the analysis time.