METHOD AND TEST KIT FOR THE DETERMINATION OF IRON CONTENT OF IN-USE LUBRICANTS

摘要

Methods for determining the iron content of an in-use lubricant, which may be used on-site are disclosed. Test kits for conducting the methods are also disclosed. In one embodiment, a method according to the invention comprises: adding a predetermined amount of said in-use lubricant to an active solvent comprising predetermined amounts of an apolar organic solvent, a polar organic solvent, an organic acid, water, an iron complexing agent and a reducing agent, said active solvent having a pH between 2 and 4; thoroughly mixing the lubricant and the active solvent until the lubricant is completely dissolved; allowing the mixture to react completely and separate into a top layer and a bottom layer, the bottom layer comprising an iron complex; filtering at least a portion of the bottom layer of the mixture directly into a receptacle suitable for absorbance measurement in the visible range; photometrically measuring the net absorbance of the filtered solution at frequencies in the visible range; and converting the absorbance measurement to ppm iron content of the lubricant.