Developing and Validating A New Method in Analysis of Metal Working Fluids

Metal working fluids sprayed in air through lathe in form of oil mist, are considered as hazardous chemical pollutant. Metal working fluids are detrimental to skin and respiratory system and they possibly may produce carcinogenic effects. Due to increasing application of lathe machines in Iranian industries and unavailability of a sensitive analytic method, the objective of this study was to develop and validate a molecular spectroscopy for analysis of metal working fluids in the air. This study was conducted in two phases of method development and examination its validity. In the first phase, 10 ml of fresh mineral undiluted mineral oil were collected in cleaned glass vial and were used to prepare standard solutions. After pre-cleaning of the mineral oil by centrifuging at 5000g, standard solutions of oil were prepared from a spiked mixed cellulose filter using chilled pentane in concentration range of 1 to 200 ppm in series of 10 ml volumetric flax. Air-borne mineral oil were sampled from the breathing zone of workers on the mixed cellulose filter membranes and after extraction by pentane, mineral oil was determined by UV-spectroscopy in the wave length range of 190-380ηm. In the second phase of this study, the new method was validated through examination of coefficient of correlation of concentrations versus their respective absorptions and coefficient of variation and recovery tests. Standard concentrations of all bulk metal working fluids obtained from lathe operations had optimum absorptions in wave length range of 190-202 ηm. Linear concentration ranges of three standard solutions were in range of 5-100 ppm and with Pearson correlation of coefficient (r2) of 0.999, 0.997 and 0.998, respectively. Coefficient of variations of the three sets of standards for inter-day and intra-day variations were in the range of 3.4-6.6 and 5.4-8.6. Recoveries of known quantity of mineral oil added to standard solutions were in the range of 100 ±10. Developed method is capable of analyzing of air-borne mineral oil in the range of 0.09-3.66 mg/m3. The developed method is by far more sensitive than other routine methods and regarding the results of its validity, it can be considered as alternative method to previous ones.