Determination of Methanol and Methyl tert-Butyl Ether in Gasoline by Infrared Spectroscopy Using the CIRCLE® Cell and Multivariate Calibration

Abstract

The feasibility of predicting concentrations of methanol and methyl tert-butyl ether (MTBE) in gasolines from the mid-infrared absorption spectra was investigated. The C-O bond stretching band region was related to these oxygenated compounds' levels with the aid of multivariate statistics. The sample spectra were taken with the use of a circular internal reflectance (CIRCLE®) cell. With the use of partial least-squares (PLS) regression a model with 18 samples was built and used to predict a set of 10 gasolines with good agreement. Two additional samples prepared with other brands of gasoline were analyzed with the same model and no matrix effects were found.

Optimization of an automated FI-FT-IR procedure for the determination of o-xylene, toluene and ethyl benzene in n-hexane

“…Examples of partial least squares ( PLS) regression techniques applied to FT-IR data include: monitoring the epoxidation of indene to indene oxide [22], and the hydrolysis of penicillin V to 6-animopenicillanic acid [23]; the determination of methanol and methyl tertiary butyl ether in gasolines [24]; chlorinated hydrocarbons in water [25], and glucose, maltose and fructose in sugar syrups [26]; and comparison of PLS with multiple linear regression ( MLS) and principal components regression ( PCR) for quantifying latex in paper coatings [27].…”

17O Quantitative Nuclear Magnetic Resonance Spectroscopy of Gasoline and Oxygenated Additives

“…A number of methods have been reported for oxygenate analysis in gasoline, most of which are based on gas chromatography (GC) , or on spectroscopic techniques such as IR, − near-IR, Raman, microwave, ,, ultraviolet visible, and mass spectrometry. , Methods that rely on GC have the limitation that oxygenates tend to coelute with the hydrocarbon constituents of gasoline, although several ways of overcoming this problem have been developed such as solvent extraction, multidimensional capillary column GC, , and the use of selective detectors such as microwave-induced plasma atomic absorption, oxygen flame ionization detector, FT-IR, and oxygen-specific mass spectrometry . Generally these methods are accurate and reliable; however, they are often tedious and time-consuming, and while many of the spectroscopic methods are nondestructive, they are often hampered by the problem of signal overlap; for instance, methanol and ethanol give overlapping IR signals .…”

“…Generally these methods are accurate and reliable; however, they are often tedious and time-consuming, and while many of the spectroscopic methods are nondestructive, they are often hampered by the problem of signal overlap; for instance, methanol and ethanol give overlapping IR signals . Many spectroscopic methods also require extensive calibration to be carried out by the use of multivariate, statistical calibration techniques …”

Enhanced Chemical Analysis Using Parallel Column Gas Chromatography with Single-Detector Time-of-Flight Mass Spectrometry and Chemometric Analysis

“…The addition of MTBE to gasoline increases octane values while reducing exhaust emissions. Several spectrometric , and gas chromatographic , techniques for the analysis of oxygenated compounds in gasoline blends have been reported. Most gas chromatographic analyses rely on relatively complex, multicolumn systems such as that described in ASTM method D4815 .…”