Solid-phase extraction for oil and grease analysis

Conventional oil and grease analysis that involves liquid-liquid extraction (LLE) has many disadvantages, which include poor reproducibility, emulsion formation, large solvent usage, and loss of volatile and semivolatile compounds during evaporation of the solvent. Therefore, an alternative method using octadecyl siloxane (C18) solid-phase extraction (SPE) columns was developed to overcome these analytical problems. The amount of the solvent was reduced and more reproducible results were obtained using this C18 SPE method. The time required for analysis is approximately the same for both methods. Higher recovery of semivolatile compounds also was obtained. The proposed C18 SPE method was also found to be comparable to those obtained from commercially available columns.