A novel procedure that uses FTIR-ATR C=O signal area (1690-1800 cm(-1)) and a standard test method that is used for determination of fatty acid methyl ester in diesel were applied for the quantification of ethyl, propyl, butyl, isobutyl, pentyl, isopenyl, hexyl, heptyl, octyl, decyl, and dodecyl fatty acid esters in diesel. These methods were examined in the range from 0.0 to 30.0 vol% of biodiesel in diesel. The obtained correlation between concentration and FTIR absorption was highly linear (R-2 above 0.993, in most cases 0.999). Considering that diesel blends with butanol or higher alcohols with their corresponding fatty acid alkyl ester can satisfy the requirements for use in diesel engines, we tested if such blending would influence the results of those two methods. The results indicate that biodiesel can be quantified for blends with alcohol content up to 9 vol% of the total volume when signal area calibration is used. (C) 2018 Elsevier Ltd. All rights reserved.