Metodologia para quantificação de potássio em folhas de arroz, soja, bananeira, parreira e limão utilizando sensor portátil

Abstract

Analytical methodology was developed for the extraction and quantification of potassium (K) in leaves and determination by a portable potassium ion-selective electrode. To ensure the portability of the analysis, a coffee grinder was used to ground the samples and the samples were weighed using a “poked” balance. Results were compared with those obtained after sample decomposition with HNO3 by heating in a conventional microwave oven and K quantification by microwave induced plasma optical emission spectrometry. A certified reference material of peach leaves was used to evaluate the accuracy of the method for K determination due to its similarity with the sample matrix. For the extraction of K, all parameters were optimized in a univariate way. The extracting solution, extracting solution temperature, total extraction time, sample mass and manual stirring time were the optimized parameters. The main advantages of the method are the portability of the analysis, low cost, use of few reagents and any trained person can perform the analysis. In addition, the method is environmentally friendly. The extraction methodology developed was applied for K determination in leaves of rice, soybean, vine, banana and lemon trees. The proposed method has good precision and accuracy. In short, it can be stated that the method can be used for routine analysis and it is portable, where the results can be achieved almost at real time.