Effects of fluid composition on mist composition.

In a reported study, mists of selected synthetic metalworking fluids were generated in laboratory experiments by two processes, nebulization (atomization) and air sparging (bubbling). Short-chain fatty acid species were determined by in situ trimethylsilyl derivatization. Comparison of relative amounts of the short-chain acids collected from mists generated by nebulization with those generated by sparging showed that the sparged mists had significantly higher amounts of neodecanoic, nonanoic, and dodecanedioic acids. Comparison of the amounts of acids collected by the resin cartridges to amounts found on the filters showed that significant losses of octanoic and isononanoic acids occurred over 8 hours of collection and that only dodecanedioic acid was not lost from the filter over a 22-hour sampling period. In another reported metalworking mist study, contaminants of metalworking fluids, e.g., tramp oils, were shown in laboratory experiments to increase the misting potential of water-based metalworking fluids. Significantly, tramp oil contamination caused less misting in synthetic fluids than soluble and semi-synthetic fluids.