ADVANCING VITAMIN DETECTION: BENZIMIDAZOLIUM SALTS AS NEXT-GENERATION SPECTROPHOTOMETRIC MODIFIERS

Abstract

Quantitative determination of vitamins such as vitamin C (ascorbic acid), vitamin B6 (pyridoxine) and vitamin E (α-tocopherol) find widespread use in pharmaceutical quality control, clinical diagnostics and nutritional studies. This purpose is often carried out using UV-Visible spectrophotometry, but much low molar absorptivity leads to poor sensitivity and high detection limits with this technique. The additional complexity of complex sample matrices, including interference and masking of analyte signals magnify these challenges. With regard to this, this paper describes the use of benzimidazolium salts as chemical modifier for improvement of spectrophotometric analysis of vitamins. The synthesized benzimidazolium salts, synthesized by methylation of benzimidazole with methyl iodide, associate with vitamins via formation of hydrogen bonds, π-π stacking and charge transfer, and enhance their optical properties. Structural integrity of the synthesized salts was also confirmed by FTIR and NMR spectroscopy. Substantial absorbance enhancements were observed upon incorporation of benzimidazolium salts into vitamin solutions. The values of increases in vitamins C 35%, B6 23% and E 42% were obtained. By such enhancement molar absorptivity improvements and detection and quantification limits improved by 20–30%, and trace level detection with better precision is allowed. The salts stabilize the excited states of vitamins and reduce matrix interferences to allow for stronger and more accurate analysis in complex matrices; mechanistic studies were performed. The modified spectrophotometric method was proven to be highly efficient and reproducible, and could be useful in pharmaceutical quality assurance and nutraceutical applications. In short, benzimidazolium salts are transformative in spectrophotometric analysis, suggesting a cheap and scalable forward path in increasing sensitivity and specificity parameters. The further application of these salts on a higher plane of bioactive compounds is possible within analytical chemistry and pharmaceutical science.