Determination of total fatty acids (C 8–C 22) in sludges by gas chromatography–mass spectrometry

Abstract

A simple method for determination of total fatty acids (C 8–C 22) in sludges down to detection limits as low as 3–5 μg/g is reported. They are extracted with dichloromethane and esterified using BF 3 methanolic solution followed by an 11 min run using gas chromatography–mass spectrometry with selected ion monitoring (GC–MS-SIM). Tridecanoic acid was used as a surrogate standard. The applicable concentration range was 8 to 3000 μg/g. The method was validated by standard addition methodology. The method was applied satisfactorily to the determination of these compounds in sludges from a waste water treatment plant in Granada (Spain).