Analysis of biodiesel and biodiesel-petrodiesel blends by high performance thin layer chromatography combined with easy ambient sonic-spray ionization mass spectrometry.

High performance thin layer chromatography (HPTLC) combined with on-spot detection and characterization via easy ambient sonic-spray ionization mass spectrometry (EASI-MS) is applied to the analysis of biodiesel (B100) and biodiesel-petrodiesel blends (BX). HPTLC provides chromatographic resolution of major components whereas EASI-MS allows on-spot characterization performed directly on the HPTLC surface at ambient conditions. Constituents (M) are detected by EASI-MS in a one component-one ion fashion as either M + Na or M + H. For both B100 and BX samples, typical profiles of fatty acid methyl esters (FAME) detected as FAME + Na ions allow biodiesel typification. The spectrum of the petrodiesel spot displays a homologous series of protonated alkyl pyridines which are characteristic for petrofuels (natural markers). The spectrum for residual or admixture oil spots is characterized by sodiated triglycerides TAG + Na. The application of HPTLC to analyze B100 and BX samples and its combination with EASI-MS for on-spot characterization and quality control is demonstrated.