IDENTIFICATION AND QUANTITATION OF OXYGENATES IN GASOLINE AMPULS USING FOURIER-TRANSFORM NEAR-INFRARED AND FOURIER-TRANSFORM RAMAN-SPECTROSCOPY

Oxygenated fuels are gasolines blended with alcohol or ether additives , The U.S. National Institute of Standards and Technology (NIST) provi des eight oxygenated gasoline standard reference materials (SRMs) each containing one of four oxygenates at both the 2.0% and 2.7% oxygen ma ss fraction levels in 20-mL sealed glass ampules, In this study, ET ne ar-IR and FT Raman spectroscopic methods were investigated to nondestr uctively identify and quantitate the oxygenate concentration in ampule s of SRM gasoline, The samples contained any one of the four SRM oxyge nates, MTBE, ETBE, TAME, or ETOH, In addition, dual-oxygenate mixtures were examined. The multivariate, statistical calibration technique, p artial least-squares, was employed for both near-IR and Raman data to obtain calibration methods to predict the mass fraction of the oxygena te in these gasoline samples, Both spectroscopic techniques were able to unambiguously identify the oxygen additives and quantitate oxygen c oncentration to an accuracy within 0.1% oxygen mass fraction.