Evaluation of the newly developed test method for the lubricant biodegradability

The conventional biodegradability test for lubricants relies on CEC L-33-A-93 worldwide, which, however, has several defects since the method determines biodegradability by C-H absorption intensity of infrared spectra. Nevertheless, the need for biodegradability tests for lubricants in various applications will continue to increase. In a previous paper the authors reported the development of a new test method by applying gas chromatography to overcome the defects of the CEC method. In this paper we examined the applicability of the new test method with various lubricant base materials and obtained good agreement with the results reported by Randles using the CEC method. Our new test method is applicable to a wider range of such lube base materials as mineral, natural, synthetic, and formulated products. Supplemental test proved that sterilization potential of biocide lasted longer than a test period of 4 weeks. Detailed gas chromatographic peak analyses on esters revealed that hydrolytic degradation did not take place under the proposed test conditions.