Salicylate Determination in Human Plasma by ISEs Incorporating Mn(III)‐Porphyrine and Zn(II)‐Dipyrromethene

All-solid-state potentiometric salicylic acid sensor for in-situ measurement of plant

Using PEDOT as the conductive polymer, an innovative small-scale sensor for directly measuring salicylate ions in plants was developed, which avoided the complicated sample pretreatment of traditional analytical methods and realized the rapid detection of salicylic acid. The results demonstrate that this all-solid-state potentiometric salicylic acid sensor is easy to miniaturize, has a longer lifetime (≥1 month), is more robust, and can be directly used for the detection of salicylate ions in real samples without any additional pretreatment. The developed sensor has a good Nernst slope (63.6 ± 0.7 mV/decade), the linear range is 10^-2 ~ 10^-6 M, and the detection limit can reach (2.8 × 10^-7 M). The selectivity, reproducibility, and stability of the sensor were evaluated. The sensor can perform stable, sensitive, and accurate in situ measurement of salicylic acid in plants, and it is an excellent tool for determining salicylic acid ions in plants in vivo.

New insights on microscopic properties of metal-porphyrin complexes attached to quartz crystal sensor

A quartz crystal adsorbent coated with 5,10,15,20-tetrakis(4-methylphenyl) porphyrin was used to examine the complexation phenomenon of three metallic ions [aluminum(III), iron(III) and indium(III)]. The aim is to select the appropriate adsorbate for metalloporphyrin fabrication. The equilibrium adsorption isotherms of tetrakis(4-methylphenyl) porphyrin were performed at four temperatures (from 300 to 330 K) through the quartz crystal microbalance (QCM) method. Subsequently, the experimental data were analyzed in order to develop a thorough explanation of the complexation mechanisms. The experimental results indicated that the aluminum(III) chloride is the adequate material for metalloporphyrin application. Theoretical investigation was established through physics adsorption models in order to analyze the experimental isotherms. The AlCl₃ isotherms were modeled via a single-layer adsorption model which is developed using the ideal gas law. Whereas, the FeCl₃ isotherms were interpreted via a single-layer adsorption which includes the lateral interactions parameters (real gas law), indicating the lowest stability of the formed iron-porphyrin complex. The participation of the chloride ions in the double-layers adsorption of InCl₃ was interpreted via layer by layer formulation. Interestingly, the physicochemical investigation of the three adopted models indicated that the tetrakis(4-methylphenyl) porphyrin adsorption was an endothermic process and that the aluminum(III) chloride can be recommended for an industrial application because it presents the highest adsorption energy (chemical bonds with porphyrins).

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.