LAUSR

A new electrochemical device based on a combination of nanomaterials such as Printex 6L Carbon and cadmium telluride quantum dots within a poly(3,4-ethylenedioxythiophene) polystyrene sulfonate film was developed for sensitive determination of amoxicillin. The morphological, structural and electrochemical characteristics of the nanostructured material were evaluated using X-ray diffraction, confocal microscopy, transmission electron microscopy and voltammetric techniques. The synergy between these materials increased the electrochemical activity, the electron transfer rate and the electrode surface area, leading to a high magnitude of the anodic peak current for the determination of amoxicillin. The electrochemical determination of the antibiotic was carried out using square-wave voltammetry. Under the optimised experimental conditions, the proposed sensor showed high sensitivity, repeatability and stability to amoxicillin determination, with an analytical curve in the amoxicillin concentration range from 0.90 to 69 μmol L-1, and a low detection limit of 50 nmol L-1. No significant interference in the electrochemical signal of amoxicillin was observed from potential biological interferences and drugs widely used, such as uric acid, paracetamol, urea, ascorbic acid and caffeine. It was demonstrated that without any sample pre-treatment and using a simple measurement device, the sensor could be an alternative method for not only the analysis of pharmaceutical products (commercial tablets) and clinical samples (urine), but also to examine food quality (milk samples).