THE DETERMINATION OF SULFUR AND CHLORINE IN USED OIL BY X-RAY-FLUORESCENCE, ICP AND ION CHROMATOGRAPHY

Methods for the determination of total sulfur and chlorine in used oil were evaluated and compared using actual waste oil samples. Oxygen bo mb combustion was followed by either ion chromatographic determination of sulfate and chloride or determination of sulfur by inductively cou pled plasma (ICP) optical emission spectroscopy. Total sulfur and chlo rine were determined by X-ray fluorescence (XRF) spectroscopy in sampl es prepared by fivefold dilution in mineral spirits. Oxygen bomb combu stion and XRF gave results with good precision, and, by comparison wit h each other, very little bias. Problems with the settling of particul ates in the XRF analyses were largely overcome by using a thin layer m ethod for sample presentation to the spectrometer. Due to the presence of particulates and emulsified water, the determination of sulfur and chlorine in used oil is more difficult than in pristine oil. Bomb com bustion, when followed by IC or ICP, and XRF have been shown to be sat isfactory analytical methods for determining total sulfur and chlorine in used or waste oil.