Integration of thin layer chromatography and smartphone-based colorimetric analysis for the detection of barbiturates

Abstract

Barbiturates, a key class of psychoactive drugs, present challenges in accurate detection due to their misuse and involvement in forensic investigations. This study introduces an innovative approach combining Thin Layer Chromatography (TLC) and smartphone-based colorimetric analysis for detecting and quantifying barbiturates extracts. Phenobarbital was extracted using liquid-liquid extraction across acidic, basic, and neutral pH levels, with optimal recovery observed in acidic conditions. TLC plates were fabricated and developed by using a chloroform-acetone solvent system (80:20), and spots were visualized using mercuric chloride diphenyl carbazone. Results showed that barbiturates extraction was highly effective in acidic conditions with hRf value for phenobarbital ranging from 58.4 to 65.0 on plate 1 and 63.2 to 63.7 on plate 2, demonstrating high consistency. RGB analysis revealed that blue color intensity was the most reliable for phenobarbital identification, with average intensities of 208 (standard) and 187.75 (samples) on plate 1 and 208.75 (samples) on plate 2. These findings, supported by validation showing specificity, linearity (R2>0.99), and precision (RSD<5%), demonstrate that integrating TLC with smartphone-based colorimetry offers a cost-effective, portable and reliable method for barbiturate analysis, with significant implications for forensic and clinical applications.