Fast economic electrochemical assay for vitamins and heavy mineral components in honey samples of different botanical origin

Abstract

Determination of heavy metals in honey samples is important as their presence indicates environmental contamination of the honey samples. The difficulty of such analysis is due to the complexity of the honey matrix because of the presence of natural honey nutrients as vitamins which can interfere in the analysis. A chemometric-based voltammetric method is used for the simultaneous estimation of some heavy metals and vitamins in different honey samples. The metals under investigation include: zinc, cadmium and lead, while the selected vitamins include: riboflavin (B2) and nicotininc acid (B3). The voltammetric analysis is fast and economic using simple inexpensive solvents and without any sophisticated sample pretreatment required. The chemometric handling is simply automated using Excel software®. The analysis is done in 0.1 M Potassium Chloride, KCl using hanging mercury drop electrode (HMDE), followed by chemometric handling of the obtained voltammetric data using first and second derivative. Then the derivative data are convoluted using 8-points sin xi polynomials (discrete Fourier functions). The proposed chemometric method facilitates the simultaneous determination of the selected metals and vitamins despite their variable responses, sensitivities and strong overlapping of their voltammetric peaks. Upon taking Zn, Pb and B3 as representative examples, their limit of quantitation (LOQ) and detection (LOD) values were greatly decreased after the chemometric treatment. The percentage decrease in their LOQ values compared to the direct method was 75%, 86% and 62% for Zn, Pb and B3, respectively. This method was successfully applied to analyze a complex mixture of some selected metals and vitamins in 12 honey samples of 6 different botanical origins without any matrix interference.