Evaluation of Sample Preparation Methods Based on Alkaline and Acid Solubilization for the Determination of Na and K in Meat Samples by Atomic Spectrometric Techniques

Two different sample preparation methods were evaluated for meat samples employing the solubilization in alkaline or acidic media. The aim of this study was to determine Na and K levels after sample solubilization with tetramethylammonium hydroxide (TMAH) at room temperature, and with formic acid and heating in a digester block at 50 degrees C for ca. 2 h. The alkaline solubilization showed to be a simple and robust method and the better alternative in relation to the mineralization conventional procedures, allowing the complete solubilization of the samples even when small quantities of TMAH were used. The method was validated by using certified reference material as well as by comparing with samples digested with nitric acid. The limits of detection obtained were 0.8 and 2.0 mu g g(-1) for Na and K, respectively, and showed to be adequate for the analysis purposes.