Direct quantitative analysis of cocaine by thin layer chromatography plus a mobile phone and multivariate calibration: a cost-effective and rapid method. Issue 42 (12th October 2016)

• Record Type: Journal Article
• Authors: Tosato, Flávia; Rosa, Thalles R.; Morais, Camilo L. M.; Maldaner, Adriano O.; Ortiz, Rafael S.; Filgueiras, Paulo R.; Gomes Lima, Kássio M.; Romão, Wanderson
• Is Part Of: Analytical methods. Volume 8:Issue 42(2016)
• Page Start: 7632
• Page End: 7637
• Publication Date: 2016-10-12
• Subjects: Chemistry, Analytic -- Periodicals; Analytical biochemistry -- Periodicals; Chemical laboratories -- Standards -- Periodicals; 543.1905
• DOI: 10.1039/c6ay02126c
• Languages: English
• ISSNs: 1759-9660

Abstract

Abstract : The detection and quantification of trace amounts of illicit substances such as crack-cocaine continues to be important for law enforcement and clinical medicine. Abstract : The detection and quantification of trace amounts of illicit substances such as crack-cocaine continues to be important for law enforcement and clinical medicine. Conventional methods available for crack-cocaine and adulterant detection include chromatography and presumptive testing. Here, we report a simple and inexpensive approach that employs a cell phone which images of thin-layer chromatography (TLC) plates were acquired to directly quantify cocaine and phenacetin in illicit samples seized in Brazil from 2012. Integration of a mobile application with a cell phone enabled immediate processing of TLC results, which eliminated the need for a bulky and expensive spectrometer. Partial least squares (PLS) regression was built using the RGB image system from the TLC plates containing cocaine (0.50 to 16.00 mg mL −1 ) and phenacetin (0.00 to 14.00 mg mL −1 ) as adulterants, acquired from a cell phone camera. The RMSEP values obtained for cocaine and phenacetin models were, respectively, equal to 1.60 and 1.36 mg mL −1, and their precision was respectively equal to 6.22 and 7.14%. No statistical difference was observed at a confidence level of 95% for both analytes calculated by the proposed method and those found by the reference method using gas chromatography with flame ionization detection (GC-FID), proving the reliability of the imaging method as an alternative approach for these assays.