Determination of Dialkyldimethylammonium Salt in Rolling Oil

DuPont ZorbaxTM C8 and NucleosilTM CN columns were used to quantitatively and qualitatively determine ArquadTM 2C-75 additive(1) in the rolling oils and the residual oils extracted from rolled aluminum products using an Indirect Photometric Chromatography (IPC) method. Two negative peaks were shown in the IPC chromatograms for most of the standard samples. The most important thing is that the first negative peak is believed to be an indication of the presence of quaternary ammonium salts. The results obtained from the analyses of several commercial quaternary ammonium salts, amines and a normal paraffin oil in different solvent systems confirm this observation. These standard compounds include dioctadecyldimethylammonium bromide, octadecyltrimethylammonium bromide, cocoamine and dimethylcocoamine. However, the chromatographic condition can only separate quaternary ammonium salts (negative peak #1) from hydrocarbons and amines (negative peak #2). That means the chromatographic condition is unable ...