Fuel mixtures : a forensic question

Abstract

Gas chromatography is one of the most frequently used and powerful tools available for separation and analysis, because of its speed, resolving power, and extreme sensitivity. For quantitative work, a calibration curve is invariably required. Intuitively, such curves are expected to be straight lines, but in practice they are usually not. I would like to present a real problem in forensic chemistry that lends itself to a practical exercise in high resolution gas chromatography, involving a nonlinear calibration curve. The reasons for the nonlinearity of the curve are discussed and the experimental curve is modelled on the basis of a simplified treatment of the analytical problem.