A Crystal Microbalance for Determination of Oil in Water
ARMY MOBILITY EQUIPMENT RESEARCH AND DEVELOPMENT COMMAND FORT BELVOIR VA
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Evaluation tests were performed on the Esso crystal microbalance to determine its suitability as a means of determining trace amounts of oil in water. Aliquots of methylene chloride used to extract the oil from the water were allowed to evaporate on one of the two balance crystals, causing a change in the beat frequency proportional to the mass of the oil. The constant relating mass and beat frequency was found to be approximately 4.3 x 10 to the - 10th power gramHz. The standard deviation of replicate aliquots of the same sample did not exceed 2 percent of the mean in the 3000- to 7000-Hz range. Standardization curves were prepared for the determination of No. 2 diesel fuel and Navy Distillate in tap water at concentrations up to 200 ppm by volume, and for the determination of mixed No. 2 diesel fueltype 9250 lubricating oil 51 by volume in tap water and in saltwater up to 100 ppm by volume.
- Civil Engineering