Electrospray Ionization Mass Spectrometry and Multivariate Calibration Analysis: A Combined Protocol To Quantify Biodiesel in Blends with Petrodiesel

Direct infusion electrospray ionization mass spectrometry (ESI-MS) and multivariate calibration were jointly used to quantify the content of biodiesel (a sample derived from a mixture of soybean oil and tallow was used as a prototype) in blends with petrodiesel. ESI mass spectra in the positive- and negative-ion modes of the aqueous/methanolic extracts of the blends in a concentration range from 0 (B0) to 20% (B20) (v/v) were acquired. The MS data were first handled with assorted pre-processing methodologies to generate the related partial least-squares (PLS) regression models. A comparative study on the performance of these models was conducted, and the very promising results obtained indicated that this methodology can be suitably applied in the determination of the content of biodiesel in blends with petrodiesel.