Determination of insolubles in diesel lubricating oil by FIA-visible spectrometry

Insolubles determination is one of the parameters usually recommended to evaluate the residual life of oil because their presence at elevated levels in diesel lubricating oil changes the viscosity, prematurely clogs filters and is one of the major factors in causing abrasive engine wear. The proposed method employs visible spectrophotometric detection in association with flow injection analysis. The results obtained by this method were compared with the ones obtained by Fourier transform infrared spectrometry (FT-IR) since this is the most employed method for insolubles determination. The proposed method presented a linear response from 0 to 3% (w/w) of insolubles in pentane (ASTM D-893). T…