Oil & Grease Analysis by Gravimetry

Interferences and Precautions:

Hexane extractable material recovered by the Oil and Grease method may include non-volatile petroleum hydrocarbons, waxes, animal fats, mineral and vegetable oils, soaps, sulfur compounds, organic dyes, chlorophyll, etc.

Mineral Oil and Grease may include any of the above components that are sufficiently nonpolar such that they are not irreversibly adsorbed to activated silica gel.

Caution is advised with the interpretation of results. This method (Organics Revision Date: Nov 6, 2015) is designed to fully recover most organic compounds with boiling points that are equal to or greater than that of nhexadecane (nC16; b.pt. 297ºC). It is not applicable to the measurement of low boiling organics like solvents or gasoline range fuels. The lighter portions of middle distillate petroleum fuels (e.g. diesels, fuel oils) may be partially lost during the solvent removal step of this method. A high bias may be achieved from co-extractives which are not oils or greases. Samples with high solids content, i.e. TSS > 500 mg/L may result in a low bias due to sorption of the material onto the insoluble fraction.

Sources:
1. Organics / Revision Date: Nov 6, 2015