Voltammetric Sensor Based on Molybdenum-Vanadium-Lithium-Borate Glassy Matrix and Its Application for the Determination of Iron in Fortified Milk Powder

Abstract

A new modified electrode was developed employing an environmentally friendly method to be used in a square-wave voltammetry technique, with advantages such as low cost, rapid response, and high sensitivity, to determine iron in milk powder samples. For this purpose, a novel lab-made electrode based on a borate glassy matrix, doped with molybdenum, lithium, and vanadium oxides, and surface modified with carbon nanoparticles was synthesized. The glassy matrix was obtained by the quenching methodology and the carbon nanoparticles were synthesized using microwave-assisted method and honey as a precursor. The voltammetric behavior of the proposed electrode was evaluated with a potassium hexacyanoferrate(II) solution. Moreover, since iron plays an important role in human nutrition, its quantification in fortified powder milk analysis employing the proposed electrode and square-wave voltammetry was studied. The linear response of iron concentration was in the range of 0.3 to 5.9 mg/L with a limit of detection of 0.18 mg/L. The iron content in the proposed method is in accordance with the inductively coupled plasma atomic emission spectroscopy values and those declared on the label. This electrochemical sensor shows great potential for the determination of iron in food samples and it can be incorporated into a portable device for in situ detection of this analyte.