Electrochemical quantification of pyridoxine (VB6) in human blood from other water-soluble vitamins

The Effect of Rare-Earth Elements on the Morphological Aspect of Borate and Electrocatalytic Sensing of Biological Compounds

Adjusting the morphological characteristics of a material can result in improved electrocatalytic capabilities of the material itself. An example of this is the introduction of rare-earth elements into the borate structure, which gives a new perspective on the possibilities of this type of material in the field of (bio)sensing. In this paper, we present the preparation of borates including La, Nd and Dy and their application for the modification of a glassy carbon electrode, which is used for the non-enzymatic detection of a biologically relevant molecule, vitamin B6 (pyridoxine). Compared with the others, dysprosium borate has the best electrocatalytic performance, showing the highest current and the lowest impedance, respectively, as determined using cyclic voltammetry and impedance tests. Quantitative testing of B6 was performed in DPV mode in a Britton-Robinson buffer solution with a pH of 6 and an oxidation potential of about +0.8 V. The calibration graph for the evaluation of B6 has a linear range from 1 to 100 μM, with a correlation coefficient of 0.9985 and a detection limit of 0.051 μM. The DyBO3-modified electrode can be used repeatedly, retaining more than 90% of the initial signal level after six cycles. The satisfactory selectivity offered a potential practical application of the chosen method for the monitoring of pyridoxine in artificially prepared biological fluids with acceptable recovery. In light of all the obtained results, this paper shows an important approach for the successful design of electrocatalysts with tuned architecture and opens new strategies for the development of materials for the needs of electrochemical (bio)sensing.

Electrochemical preparation and the characterizations of poly(3,5-diamino 1,2,4-triazole) film for the selective determination of pyridoxine in pharmaceutical formulations

This work describes the synthesis and characterization of a polymeric film of 3,5-diamino 1,2,4-triazole on a pencil graphite electrode for the selective sensing of pyridoxine (PY). The PGE was modified using the electropolymerization process by the potentiodynamic method. The polymerized electrode (PDAT/PGE) was characterized by IR, SEM, AFM, cyclic voltammetry, and electrochemical impedance spectroscopy. PY undergoes irreversible oxidation at 0.79 V on PDAT/PGE in phosphate buffer of pH 5. Using the differential pulse voltammetric technique (DPV), PY showed a linear range from 5 to 950 μM with a lower detection limit of 2.96 μM. The PDAT/PGE was applied for the analytical determination of PY in pharmaceutical tablets with good recovery.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s11696-023-02777-5.

Rapid determination of folic acid and riboflavin in urine by polypyrrole magnetic solid-phase extractant combined ultra-performance liquid chromatography

Determination of folic acid and riboflavin in biological samples is difficult due to their high polarity, low concentration, chemical instability, and complex matrix. In this study, the polypyrrole-coated magnetic nanocomposite (Fe₃O₄@PPy) was synthesized innovatively with the assistance of hexadecyltrimethylammonium bromide. To evaluate the adsorption mechanism and the feasibility of synthesized Fe₃O₄@PPy as an adsorbent, the adsorption capacities, kinetics and thermodynamics of folic acid and riboflavin were investigated systemically. Furthermore, in light of the chemical instability of folic acid and riboflavin a method for rapid extraction and detection of them from human urine within 10 min was developed successfully by combining magnetic solid phase extraction with ultra-performance liquid chromatography (MSPE/UPLC). The adsorption parameters including sorbent amount, pH value, extraction time, desorption solvent and desorption time were studied. Under optimum conditions, the performance of the established determination method was validated with the linearly dependent coefficients (>0.9995), the limits of detection (0.02-0.05 µg/mL), the limits of quantification (0.07-0.18 µg/mL), and the recoveries (92.2-105.1%, with relative standard deviation < 3.3%). The rapid extraction and detection of folic acid and riboflavin from real urine samples were achieved subsequently. The present study suggests that the developed method exhibits a promising application in the analysis of free folic acid and riboflavin in human urine samples, which can provide a reference for the clinical drug monitoring and treatment.