Potentiometric Sensor Arrays Based on Hybrid PFSA/CNTs Membranes for the Analysis of UV-Degraded Drugs

Protein-Aided Synthesis of Copper-Integrated Polyaniline Nanocomposite Encapsulated with Reduced Graphene Oxide for Highly Sensitive Electrochemical Detection of Dimetridazole in Real Samples

Dimetridazole (DMZ) is a derivative of nitroimidazole and is a veterinary drug used as an antibiotic to treat bacterial or protozoal infections in poultry. The residues of DMZ cause harmful side effects in human beings. Thus, we have constructed a superior electrocatalyst for DMZ detection. A copper (Cu)-integrated poly(aniline) (PANI) electrocatalyst (PANI-Cu@BSA) was prepared by using a one-step method of biomimetic mineralization and polymerization using bovine serum albumin (BSA) as a stabilizer. Then, the synthesized PANI-Cu@BSA was encapsulated with reduced graphene oxide (rGO) using an ultrasonication method. The PANI-Cu@BSA/rGO nanocomposite had superior water dispersibility, high electrical conductivity, and nanoscale particles. Moreover, a PANI-Cu@BSA/rGO nanocomposite-modified, screen-printed carbon electrode was used for the sensitive electrochemical detection of DMZ. In phosphate buffer solution, the PANI-Cu@BSA/rGO/SPCE displayed a current intensity greater than PANI-Cu@BSA/SPCE, rGO/SPCE, and bare SPCE. This is because PANI-Cu@BSA combined with rGO increases fast electron transfer between the electrode and analyte, and this synergy results in analyte-electrode junctions with extraordinary conductivity and active surface areas. PANI-Cu@BSA/rGO/SPCE had a low detection limit, a high sensitivity, and a linear range of 1.78 nM, 5.96 μA μM-1 cm-2, and 0.79 to 2057 μM, respectively. The selective examination of DMZ was achieved with interfering molecules, and the PANI-Cu@BSA/rGO/SPCE showed excellent selectivity, stability, repeatability, and practicability.

Perfluorosulfonic Acid Membranes with Short and Long Side Chains and Their Use in Sensors for the Determination of Markers of Viral Diseases in Saliva

The development of accessible express methods to determine markers of viral diseases in saliva is currently an actual problem. Novel cross-sensitive sensors based on Donnan potential with bio-comparable perfluorosulfonic acid membranes for the determination of salivary viral markers (N-acetyl-L-methionine, L-carnitine, and L-lysine) were proposed. Membranes were formed by casting from dispersions of Nafion or Aquivion in N-methyl-2-pyrollidone or in a mixture of isopropyl alcohol and water. The influence of the polymer equivalent weight and the nature of dispersing liquid on water uptake, ion conductivity, and slope of Donnan potential for the membranes in H+ and Na+ form was investigated. The varying of the sorption and transport properties of perfluorosulfonic acid membranes provided a change in the distribution of the sensor sensitivity to N-acetyl-L-methionine, L-carnitine, and L-lysine ions, which was necessary for multisensory system development. The simultaneous determination of three analytes, and the group analysis of them in artificial saliva solutions, was performed. The errors of N-acetyl-L-methionine and L-carnitine determination were 4-12 and 3-11%, respectively. The determination of L-lysine was complicated by its interaction with Ca2+ ions. The error of the group analysis was no greater than 9%. The reverse character of the viral markers' sorption by the membranes provided long-term sensor operation.