Due to the concern about the health damage caused by the consumption of food and water contaminated by highly toxic heavy metals, the quantification of these chemical species has led research fields, such as material science and electrochemistry, to develop new analytical methodologies for the determination of these contaminants even at trace levels. In this sense, the use of ion-imprinted polymers for the surface modification of electrodes has improved the sensitivity and selectivity of methodologies for the electrochemical detection of metals due to the specific molecular recognition capability of the polymer. This strategy allows the design of low-cost, sensitive, precise, and accurate electroanalytical methodologies with excellent selectivity when used in the analysis of complex samples. This review discusses recent advances in the development of electroanalytical methodologies based on ion-imprinted polymers for their application in the determination of heavy metals in food and drinking water samples. Topics about the monomers used for the synthesis of the ion-imprinted polymers, their influence on the polymer characteristics, the electrode modification procedure, the electrode composition, and the electrochemical analysis conditions used are addressed.

It is well known that Pb(II) is considered a highly toxic metal. The slight difference between toxic and permissible levels in drinking water is a matter of concern; therefore, highly sensitive and selective techniques have been proposed for quantification, such as the electrochemical ones. In this work, an easy, simple, low-cost, and high selective sensor based on carbon paste electrodes (CPE) and ion-imprinted polymers (IIP) is proposed for Pb(II) analysis in real water samples. Recognition cavities, selective to Pb(II), were synthesized based on a cross-linked polymer using vinyl pyridine. A modified CPE was constructed by a mixture of graphite powder, IIP, and paraffin oil. By voltammetry studies, a notable difference was observed in the electrochemical response of the electrodes modified with IIP and those with non-imprinted polymer (NIP), confirming the existence of the recognition cavities in the IIP. The construction and analysis parameters related to the analytical response of Pb(II) (anodic current intensity of stripping voltammetry), were optimized; the selectivity was also studied considering potential interference ions. A linear concentration range from 3.3 mg l⁻¹ to 33 mg l⁻¹ and a limit of detection of 0.99 mg l⁻¹ were achieved. Pb(II) was successfully quantified in real complex samples without previous treatment.

Glucose is the principal source of energy for humans and its quantification in physiological samples can diagnose or prevent diseases. Commonly, glucose determination is based on spectrophotometric-enzymatic techniques, but since at least a decade ago, electroanalytical strategies have emerged as promising alternatives providing accuracy and precision in the determination of biomolecules. This review focuses on the development of non-enzymatic methodologies based on modified electrochemical sensors with molecularly imprinted polymers (MIPs) for glucose detection sensors in physiological samples (blood, saliva, and urine). The trends in the construction of non-enzymatic sensors base on MIP combine with materials such as carbonaceous materials, metal nanoparticles, and polymers improving their electrocatalytic properties and analytical parameters of the electro-analytical methodologies developed. Glassy carbon electrodes, carbon paste electrodes, and screen-printed electrodes are the main transductors modified with MIP for the electrochemical oxidation of glucose, and the maximum anodic peak current is taken to the analytical signal. In all reported non-enzymatic sensors, the presence of the MIP improved glucose determination compared to the bare working electrode. The reported results demonstrated that this electroanalytical approach represents a viable alternative for fast and confident analysis of the glucose molecule overcoming the drawbacks presented by enzymatic sensors.

Glucose is the principal source of energy for humans and its quantification in physiological samples can diagnose or prevent diseases. Commonly, glucose determination is based on spectrophotometric-enzymatic techniques, but at least since a decade ago, electroanalytical strategies have emerged as promising alternatives providing accuracy and precision in the determination of biomolecules. This review focuses on the development of non-enzymatic methodologies based on modified electrochemical sensors with Metal-Organic Frameworks (MOF) for glucose detection sensors in physiological samples (blood and urine). Glassy carbon electrodes (GCE), carbon paste electrodes (CPE), and screen-printed electrodes (SPE) are the main transductors modified with MOF for the electrochemical oxidation of glucose, and the maximum anodic peak current is taken to the analytical signal. The reported results demonstrated that this electroanalytical approach represents a viable alternative for fast and confident analysis of the glucose molecule.

In this work, a carbon paste electrode was modified using Bi2O3 nanoparticles (NPs) for the determination of Acetaminophen (ACP) in human urine samples using differential pulse voltammetry as the quantitative analytical method, which was optimized using a Box-Behnken design. The Bi2O3-NPs/CPE sensor demonstrated excellent ACP oxidation performance with two linear ranges of 50 µM - 1000 µM a 1000 µM -10000 µM. The statistical analysis, low interference when other chemical species are present, and high reproducibility and repeatability shown that the recommended method for measuring ACP in human urine samples is exactly as effective as the spectrophotometric method. Bi2O3 nanostructures provided an important modifier for the development of an efficient electrochemical method to determine ACP in physiological samples.