CONTAINED IN VOL. 05.05, 2018 Defines a rapid screening method using flow analysis by Fourier Transform Infrared (FA-FTIR) spectroscopy with partial least squares (PLS) processing for the quantitative determination of the fatty acid methyl ester (FAME) contamination of middle distillates, in the range of 20 mg/kg to 1000 mg/kg, and of middle distillates and residual fuels, following dilution, for levels above 0.1%.