Determinación de cadmio en leches crudas usando un biosensor amperométrico

Abstract

Introduction. Cadmium is a metal that has been found in milks and, therefore, represents a big risk for human health. Biosensors have been used as tools for the rapid determination of this kind of compounds in several matrices. Materials and methods. An amperometric biosensor and screen printed electrodes were used to immobilize the urease enzyme, by the use of the cross linking method. The subtract used for the determination was urea. Before determining the cadmium concentration in the milk, the method used was validated by making calibration curves and evaluating the repeatability of both the method and the instrument. Results and discussion. The linear rank for the method was 5 mM to 60 mM with a high correlation between variables. The quantification limit of the method was 0.05 mg/L. The variation coefficient was 7.55 % for the method´s repeatability tests, which indicates a high precision of the results. From the milk samples analyzed, recovery percentages above 80% were obtained. This means a low matrix effect, keeping in mind that milk has a high degree of interfering elements for this kind of methods. Conclusion. The amperometric biosensor demonstrated to be an efficient and fast tool to determine cadmium in milks, and this can be helpful to improve the milk´s quality in swine farms.