Quantitative applications of fluorescence and ultraviolet scanning densitometry for compositional analysis of petroleum products in thin-layer chromatography

Direct application of the fluorescence response enhancement (derived from the interaction of the berberine cation with saturated hydrocarbons) to petrochemical analysis is achieved. Hydrocarbon types are successfully determined in middle (gasoil) and heavy (lubricants, vis-breaking fuel, heavy oil) petroleum distillates with adequate precision and sensitivity. The novelty of this method resides in the fact that a single fluorescence scanning is only needed for the determination of saturates and aromatics in the same chromatogram. In spite of their chemical inertness, saturated hydrocarbons can be quantitatively determined using thin-layer Chromatographic densitometry. The fluorescent response depends on the alkane structure. A reliable analysis depends on the adequate choice of variables that influence fluorescence response, precision, and sensitivity: sample load, application volume, beam size, and impregnation conditions (berberine concentration and impregnation time). Sensitivity of the analysis can be tailored to a certain extent through control of the last parameter. The quantitative results agree with those provided using other well-established techniques in the petrochemical industry.