A New Approach to The Determination of Oil Andgrease in Water and Wastes

Performance of oil and grease (OG) determination using IR was evaluated using figures of merit as required by the new ASTM method and ISO 17025. The evaluation included LOQs, long-time stability of standard, spiking and sample extracts, and recoveries from laboratory samples. Fitness of purpose was established by participation in a NELAC proficiency test, the value obtained being well within the statistically defined range of acceptance. The direct S-3l6 extraction-infrared (IR) method also enabled analysis of the same waste samples with silica gel. Emphasis was placed on overcoming emulsions using ultrasonic and solid phase extraction (SPE). It can be concluded that this new ASTM procedure using S-316 extraction provides a convenient and reliable means for compliant OG determination using the cost-effective IR technique. A disadvantage is the high cost of the S-316 solvent. However time saved and high sample throughput justifies the cost of operation.