Ultrasensitive determination of selenium in foodstuffs and beverages using an electroanalytical approach

Abstract

This work describes the development of an electroanalytical methodology to the determination of nanomolar levels of selenium, which is sensitivity, selectivity, simple, low cost, quickness, and robustness. Therefore, it was employed a silver solid amalgam electrode modified by a thin and stable mercury film (f-AgSAE) allied to square-wave cathodic adsorptive stripping voltammetry (SWCASV). Besides this, the adsorptive and square-wave voltammetry parameters were previously optimized following the built of analytical curves in the linear range from 1.00 × 10−7 to 8.00 × 10−6 mol L−1, that resulted in a correlation coefficient of 0.9989, repeatability of 1.64%, reproducibility of 4.90%, detection limit of 1.01 × 10−9 mol L−1 and quantification of 3.36 × 10−9 mol L−1. This methodology proposed can be compared with similar data obtained by sophisticated spectroscopic techniques and other electroanalytical techniques. The procedure proposed was applied to selenium determination in in natura food (apple, orange, potato, spinach and tomato) and beverage (coconut water, soy juice and soy milk) samples. These samples were digested using a simple procedure that resulted in very satisfactory recovery percentages, confirming suitable robustness of the proposed methodology.