Application of polyaniline for potentiometric recognition of salicylate and its analogues

Solid-state ion-selective electrodes for the first potentiometric determination of the anti-COVID 19 drug Remdesivir in human plasma; A comparative study

Establishing sensitive and targeted analytical methodologies for drug identification in biological fluids as well as screening of treatments that can counteract the most severe COVID-19 infection-related side effects are of utmost importance. Here, first attempts have been made for determination of the anti-COVID drug Remdesivir (RDS) in human plasma using four potentiometric sensors. Calixarene-8 (CX8) was used as an ionophore applied to the first electrode (Sensor I). The second had a layer of dispersed graphene nanocomposite coating (Sensor II). (Sensor III) was fabricated using nanoparticles of polyaniline (PANI) as ion-to–electron transducer. A reverse-phase polymerization using polyvinylpyrrolidone (PVP) was employed to create a graphene-polyaniline (G/PANI) nanocomposite electrode (Sensor IV). Surface morphology was confirmed by Scanning Electron Microscope (SEM). UV absorption spectra and Fourier Transform Ion Spectrophotometry (FTIR) also supported their structural characterization. The impact of graphene and polyaniline integration on the functionality and durability of the manufactured sensors was examined using the water layer test and signal drift. In the ranges of concentration of 10⁻⁷ to 10⁻² mol/L and 10⁻⁷ to 10⁻³, sensors II & IV exhibited linear responses; respectively while sensors I & III displayed linearity within 10⁻⁶ to 10⁻² mol/L. The target drug was easily detectable using LOD down to 100 nmol/L. The developed sensors satisfactorily offered sensitive, stable, selective and accurate estimate of Remdesivir (RDS) in its pharmaceutical formulation as well as spiked human plasma with recoveries ranging from 91.02 to 95.76 % with average standard deviations less than 1.85. The suggested procedure was approved in accordance with ICH recommendations.

Pentamethinium Salts Nanocomposite for Electrochemical Detection of Heparin

This study presents a simple route to heparin detection and develops a voltammetric approach using supramolecular principles and nanomaterials. Nanocomposites, including gold nanoparticles (AuNPs) and γ-substituted pentamethinium salts (PMS) deposited on a glass carbon (GC) electrode surface (GC/AuNPs/PMS) and covered by a plasticized poly(vinyl chloride) (PVC) membrane, are proposed for heparin detection. The conductivity of the nonconducting PVC-plasticized membrane is guaranteed by AuNPs, and the selectivity is provided by the interaction between γ-substituted PMS and anionic analytes. In order to extend the linear range, it is necessary to apply a solvent compatible with PVC-plasticized membrane, namely tetrahydrofuran. The proposed voltammetric sensor showed a concentration dependence from 1.72 up to 45.02 IU mL⁻¹ heparin and was used for heparin detection in saline and biological samples with recovery of 95.1–100.9%.

Solid-Contact Potentiometric Sensors and Multisensors Based on Polyaniline and Thiacalixarene Receptors for the Analysis of Some Beverages and Alcoholic Drinks

Electronic tongue is a sensor array that aims to discriminate and analyze complex media like food and beverages on the base of chemometrics approaches for data mining and pattern recognition. In this review, the concept of electronic tongue comprising of solid-contact potentiometric sensors with polyaniline and thacalix[4]arene derivatives is described. The electrochemical reactions of polyaniline as a background of solid-contact sensors and the characteristics of thiacalixarenes and pillararenes as neutral ionophores are briefly considered. The electronic tongue systems described were successfully applied for assessment of fruit juices, green tea, beer, and alcoholic drinks They were classified in accordance with the origination, brands and styles. Variation of the sensor response resulted from the reactions between Fe(III) ions added and sample components, i.e., antioxidants and complexing agents. The use of principal component analysis and discriminant analysis is shown for multisensor signal treatment and visualization. The discrimination conditions can be optimized by variation of the ionophores, Fe(III) concentration, and sample dilution. The results obtained were compared with other electronic tongue systems reported for the same subjects.

Silica-titania xerogel for solid phase spectrophotometric determination of salicylate and its derivatives in biological liquids and pharmaceuticals

BACKGROUND

Salicylic acid and its derivatives are widely used drugs with potential toxicity. The main areas of salicylate derivatives determination are biological liquids and pharmaceuticals analysis.

RESULTS

Silica-titania xerogel has been used for solid phase spectrophotometric determination of various salicylate derivatives (salicylate, salicylamide, methylsalicylate). The reaction conditions influence on the interaction of salicylate derivatives with silica-titania xerogels has been investigated; the characteristics of titanium(IV)-salicylate derivatives complexes in solid phase have been described. The simple solid phase spectrophotometric procedures are based on the formation of xerogel incorporated titanium(IV) colored complexes with salicylate derivatives. A linear response has been observed in the following concentration ranges 0.1-5, 0.5-10 and 0.05-4.7 mM for salicylate, salicylamide, and methylsalicylate, respectively. The proposed procedures have been applied to the analysis of human urine, synthetic serum, and pharmaceuticals.

CONCLUSIONS

The simple solid phase spectrophotometric procedures of salicylate derivatives determination based on the new sensor materials have been proposed for biological liquids and pharmaceuticals analysis. Graphical abstractComplexation of titanium (IV), incorporated in silica-titania xerogels (Si-Ti), with salicylate derivatives (L) resulting in yellow-colored xerogels (Si-Ti/Ln) has been proposed for salicylate derivatives determination in biological liquids and pharmaceuticals.