[Study on the Detection of Trace Sulphur in Diesel with Inductively Coupled Plasma Optical Emission Spectroscopy]

The method to detect trace sulphur content in diesel with inductively coupled plasma optical emission spectrometry (ICP-OES) was established. Kerosene sample was directly diluted, and then trace sulphur content in the solution was analyzed directly with ICP-OES. High concentrations of organic solvents with high saturation vapor pressure can cause the increasing of the loading of plasma, which would interfere the determination. In order to keep the working stability of equipment, operating parameters, such as RF power, loading gas velocity, were being optimized. First, the axially-viewed technology was adopted to increase the sensitivity of determination. Second, the analysis spectral lines of sulfur are located in ultraviolet area; therefore the Ar was adopted as protective air, and increase Ar clean time to keep the pure of sight source. Third, the condensation and deposition of high concentrations of carbon could be avoided effectively by introducing O2 to plasma. Some detailed processes were used to further keep the stability of determinate signals such as: using element Y as internal standard to correct matrix effectives and compensate the errors caused by the spectral line shift, some automatic software were used to correct signal background. The results showed that the detection limits was 0.2 μg·L-1, the relative standard deviation (RSD) was in range of 1.6%~2.1%, and the recovery of the methods was in range of 97.4%~101.8%. The method has the following advantages: simple sample pretreatment, fast analyzing speed, low detection limitation, high precision and accuracy, as well as wide linear dynamic range. It can be used for rapid analysis of trace sulfur in diesel.