Determination of oil and grease by solid phase extraction and infrared spectroscopy

Abstract

An alternative procedure using solid phase extraction for the analysis of oil and grease in waters was developed. The use of a PTFE filter as a solid phase allows retention of oil and grease and further analysis of carbon–hydrogen bonds can be run over the filter. This method avoids the use of any kind of solvent. Experiments used n-hexadecane as a standard oil in different water matrices. The detection limit was 0.034 mg/l. Recoveries of diesel oil, pump vacuum oil, olive oil, sunflower oil and mixture of oils, depend strongly on the oil used for the calibration line, but in general satisfactory results were obtained. Recoveries of isooctane and benzene, used in the standard methods procedure, gave poor results. The method is fast, clean and sensitive, and represents a way of measuring oil and grease in water with high reproducibility. The method was compared with standard methodologies in tests involving real samples.