Application of molecularly imprinted electrochemical sensor for trace analysis of Metribuzin herbicide in food samples.

Metribuzin (MTZ) is an important herbicide widely used in fields and represents a big threat to the environment and health. Herein, an electrochemical sensor was designed for its detection in commercial product (Egyscor® 70%), spiked tomatoes and potatoes samples with recovery values ranging from 97.12 to 103.41%. Bulk-polymerized MTZ molecularly imprinted polymer (MIP) was developed, using itaconic acid (functional monomer), ethylene glycol dimethacrylate (cross-linker) at an optimum molar ratio 1:5:30, respectively. Differential pulse voltammetry was used to examine the optimization variables of the MIP based sensor such as the variation of (template: monomer: cross-linker) ratio, accumulation time, multi walled carbon nanotubes amount, pH and scan rate, while cyclic voltammetry and electrochemical impedance spectroscopy were used to characterize the sensor. The sensor showed selective adsorption ability and a good linearity over the concentration range of 0.2 ng/mL to 21.429 µg/mL, with LOD and LOQ of 0.1 pg/mL and 0.3 pg/mL, respectively.

SARS-CoV-2-Impedimetric Biosensor: Virus-Imprinted Chips for Early and Rapid Diagnosis.

Due to the current global SARS-CoV-2 pandemic, rapid and accurate diagnostic tools are needed to prevent the spread of COVID-19 across the globe. An electrochemical sensing platform was constructed using CNTs/WO3-screen printed electrodes for imprinting the complete virus particles (SARS-CoV-2 particles) within the polymeric matrix to create viral complementary binding sites. The sensor provided high selectivity toward the target virus over other tested human corona and influenza respiratory interference viruses. The sensitivity performance of the sensor chips was evaluated using different viral concentrations, while the limits of detection and quantification were 57 and 175 pg/mL, respectively. Reaching this satisfied low detection limit (almost 27-fold more sensitive than the RT-PCR), the sensor was applied in clinical specimens obtained from SARS-CoV-2 suspected cases. Thus, dealing directly with clinical samples on the chip could be provided as a portable device for instantaneous and simple point of care in hospitals, airports, and hotspots.

Molecularly imprinted polymers for selective extraction of rosmarinic acid from Rosmarinus officinalis L.

This study provides a robust and reproducible approach for selective extraction of rosmarinic acid (RA) using molecularly imprinted polymers (MIPs). Computational modeling and UV spectroscopic analysis were performed to optimize MIP synthesis. Consequently, six different bulk and surface imprinted polymers were generated using RA as the template. Binding performance of the imprinted polymers was evaluated using static equilibrium and complementary dynamic rebinding experiments. Despite the high selectivity of thus generated surface imprinted polymers, the corresponding bulk polymers exhibited better binding performance when serving as sorbents during solid phase extraction (SPE). An optimized molecularly imprinted solid phase extraction (MISPE) protocol was developed in respect to loaded amount of RA, composition of the loading solution, washing solvent, and elution volume. Thereby, a remarkably selective extraction of RA from real-world Rosmarinus officinalis L. extract with a recovery rate and purity of 81.96 ± 6.33% and 80.59 ± 0.30%, respectively, was achieved.