Voltametría de onda cuadrada para determinar cadmio en almendras de cacao (theobroma cacao): nacional e injerto del Cantón Santa Rosa

Abstract

Cocoa cultivation is of great economic, social and environmental importance, establishing itself as a recognized raw material in international markets, for Ecuador it represents one of the most important activities after bananas, as it is essential as a raw material for the production of high quality chocolate, which is why producers and exporters have been concerned with controlling that Cocoa products do not contain degrees of toxicity , with respect to heavy metals such as cadmium that accumulates in almonds, poseing a threat to consumer health, since excessive accumulation of this metal can lead to the formation of kidney stones, acute pneumonitis with pulmonary edema which contributes to the development of lung cancer. Therefore, this study is based on the validation and development of a voltamperometric technique by Square Wave Voltametry (SWV) for the determination and quantification of cadmium in almonds of two cocoa varieties; and graft from two farms located in the Canton Santa Rosa, where metallurgical activities are carried out that generate residues of heavy metals such as cadmium, causing contamination of the water resource, the Santa Rosa river, which is used for irrigation of cocoa crops, causing pollution rates in their content. For the analysis of cocoa almonds, a random sampling of the cocoa cobs was performed, then a quartet to take a representative sample and then moved to the laboratory for the respective drying on a stove at 75oC for one day, the dried samples are removed from the shell and with the help of a mortar the seeds are crushed , it proceeds with calcination in crucibles at 400oC for 8 hours, it was then transferred to a desiccator to cool down and undergo the acid digestion process, finally for voltametric analysis validation parameters were established such as: accuracy, accuracy, linearity, sensitivity, detection limits and quantication, obtaining satisfactory results, with a determination coefficient R2 x 0.9987. A Gold-tipped Teflon electrode was labeled in the electrolytic medium of Tiourea 0.01 mol L-1 + sulphuric acid 0.0035 mol L-1 with a pH 2.4, applying parameters of: f= 60Hz; ΔEp= 60mV; ΔEs= 50mV, considered the most optimal for the SWV technique.