Systematic investigations in order to quantify cooling lubricant constituents taking into account methodological and preventive, practice-related aspects of work protection

Status:

completed 09/1997

Aims:

Cooling lubricants in principal contain a number of problematic substances. Until now only a few of these are routinely classified. For other substances up to date there are no ideal routine laboratory analysis procedures. Goal: evaluating of capillary electrophoresis as a universal analysis method for cooling lubricants for determination of nitrate/nitrite, amines and carbolic acid components (in total 55 individual substances)

Activities/Methods:

The development of procedures corresponding with practice, field tests in work related use (cooling lubricant concentrates, cooling lubricant emulsions, fresh and after long periods of use, aerosol analysis)

Results:

Capillary electrophoresis enables the following: short analysis times, on-column-detection, efficient separation with a high degree of selectivity, low buffer use, minimal sample volumes, minimum preparation of samples required, few waste products requiring disposal; good reproducibility (relative StD 1.5 to 7.3 %); detection limits in the mg/l-range. All important alkanole amines are quantifiable. For 31 cooling lubricant concentrates the results correspond closely the manufacturers' specifications. The commercial products remain within the TRGS (secondary amines) limit value, several exceed the limit value for diethanole amine. 18 anions from inorganic carbonic acids were quantified by indirect UV-detection. Unacceptable levels of nitrite from 8 to 230 g/ml were detected in four products. Capillary zone electrophoresis enabled 13 corrosion inhibitors and biocides to be determined simultaneously. Phenoxylalcohol contents ranging from 2 to 15 % were detected using micelle electrokinetic chromatography with direct UV-detection, one product contained 60 mg/l phenol.

Last Update: