Anew alternative method for quantitative analysis by thin layer chromatography using a lab-made multi-track device and image-based chromatograms

摘要

This work describes a simple, low-cost, and innovative approach to perform quantitative analyses by thin layer chromatography (TLC) combined with image-based detection with UV revelation, which enables the acquisition of chromatograms. Lab-made aluminium TLC devices containing eight individual tracks with thin fluorescent silica layers were developed, evaluated, and used to perform the separation and quantification of acetaminophen (ACM), caffeine (CAF), and acetylsalicylic acid (ASA) in medicine tablets by using image-based detection performed with a webcam and software written in VisualStudio. The proposed device enables vertical development of the separation with proper reproducibility of retention factors (< 2%) and of the peak heights (< 8%), without occurrence of silica damage, demonstrating the applicability of the new approach. By using a mixture of ethyl acetate/acetic acid (80:2 v/v) as eluent, analytical curves were obtained for the analytes based on the chromatographic peak heights, providing linear relationships (R > 0.996) for the studied concentration ranges ACM (0.18-0.54 mg mL(-1)), CAF (0.50-3.00 mg mL(-1)) and ASA (0.70-4.50 mg mL(-1)) with estimated limits of detection (LOD) of 0.14 mg mL(-1), 0.40 mg mL(-1) and 0.56 mg mL(-1), for ACM, CAF and ASA, respectively. In addition, no significant differences (95% confidence level) were observed by comparing the average concentration of the analytes determined by the proposed method and those obtained by a reference HPLC based method, indicating an adequate accuracy of the procedures.