INFRARED SPECTROGRAPHIC ANALYSIS OF SOME PRESERVATIVE, HYDRAULIC, AND SPECIALTY FLUIDS

An effort was made to ascertain whether infrared spectrographic analysis could detect changes in composition of formulations of preservative, hydraulic and specialty fluids. Limits of detection of additives were estimated using both spectra compensated by base oil in the reference beam of the spectrophotometer and simple, or uncompensated spectra. Petroleum type base oils for VV-L-800 and MIL-H-46004 and a tetra-alkyl silicate base fluid for MIL- L-14107 were used. Additives studied were several corrosion inhibitors, antioxidants, antiwear agent, a hydrolysis inhibitor, a pour point depressant and a dye. It was found that the heavy absorption of the silicate base oil obscured absorption bands of all additives tested in it. In the petroleum base oils the corrosion inhibitors and tricresyl phosphate were easily detected. The remaining additives are used near or below their detection limits. Use of the formulation's base oil in the reference beam improved the limit of detection of additives. It was concluded that the infrared spectrogram cannot accurately detect changes in formulation.