High performance thin layer chromatography with eluents containing SDS aided by UV- and Raman spectroscopy.

The modification of non-polar silica gel plates by aqueous-organic solvent containing sodium dodecyl sulphate was investigated. The changes that occurred in the sorbent were examined using the Raman spectroscopy technique. The abovementioned technique was also involved in the investigation of carbamazepine-SDS complexes. The approach of applying the Raman spectroscopy into the investigation of the chromatographic behavior of SDS, carbamazepine and RP-18 W sorbent was presented for the first time. The effect of sodium dodecyl sulphate, SDS, concentration on the chosen drug used in neurodegenerative disorder (sulpiride, olanzapine, carbamazepine, trazodone, clomipramine, and pridinol) retention has been investigated. Such examination for these medicines has been presented for the first time for thin-layer chromatography system. Modified the mobile phase composition has resulted in the separation of the mixture containing all compounds. To confirm micellar forming, critical micelle concentration for SDS in the applied mobile phase was determined using two techniques, i.e., conductometric and spectrophotometric with azorubine as the indicator. The effect of surfactant on the solute zone shape by means of tailing and asymmetry factors has been determined. For four of the six investigated compounds, these factors have been close to 1.0. The separation efficiency measured by the height of the theoretical plate varies from 39 to 73 μm depending on the solute investigated. The method has been optimised regarding the quantitative analysis of investigated compounds, opening up new possibilities for drug analysis. In terms of the LOD values are in the range of 0.22 µg/spot to 1.67 µg/spot, whereas LOQ values are in the range of 0.66 µg/spot to 5.07 µg/spot for olanzapine and trazodone, respectively. Furthermore, the method was also applied for the quantitative analysis of the investigated compounds in pharmaceutical preparations. Such proceedings for RP-18 W TLC system containing SDS was shown for the first time. The new method has better or comparable concentration ranges regarding some of investigated compounds to those presented previously. Additionally, for the first time, a strategy involving various techniques (TLC chromatography supported by UV- and Raman spectroscopy and conductometry) for complex analysis of the separation system was presented, inspiring potential future research directions.