In this article, our research group evaluates differences between standard thin-layer chromatography (TLC) and modern quantitative thin-layer chromatography (QTLC). Several most important reasons which transformed a simple powerful analytical technique, suitable for inorganic, organic, and biological samples, into reliable and regulatory acceptable technique in our laboratory are described. TLC has been accepted as good semi-qualitative technique, but a long and intensive developing period was necessary before QTLC became a respectable quantitative analytical technique. This breakthrough has been obtained with automation of main analytical task, standardization of analytical procedures, and application of operational qualification and performance qualification (OQ/PQ). Development of digital technology with capable microcomputers, image processing devices, big memory, new communication option, and new software enable in-line introduction of quality assurance (QA) principles in our laboratory. Agroup of new instruments, in some details, also a result of our research, enable simple and reliable analytical work. Results obtained with Automatic Developing Chamber 2 (ADC2) in very sensitive quantification of lutein and β-carotene demonstrated how controlled separation parameters significantly improved chromatographic parameters. In our experiment, relative standard deviation (RSD) of retardation factor (RF) for lutein and β-carotene spots were 3.70% and 1.65% in classic TLC chamber and only 2.48% and 0.94% in ADC2 chamber. Instruments may be qualified, and final results are then reported with reliable realistic error based on standardized analytical procedures. Implementation of QA system, analytical management, educated and trained staff, qualified instruments, and standard operating procedures ensure requisite reliability of our TLC analysis.
International Organisation for Standardisation, Guide to the Expression of Uncertainty in Measurements, ISO, Geneva, 1995.