ESTIMATION OF MEASUREMENT UNCERTAINTY FOR THE DETERMINATION OF THE TOTAL SULFUR CONTENT IN PETROLEUM AND PETROLEUM PRODUCTS IN UV-FLUORESCENTANALYSIS

The measurement uncertainty was estimated for the determination of sulfur content in petroleum and petroleum products according to the recommendations of the EURACHEM/CITAC Guide and ―Guide to the expression of uncertainty in measurement (GUM)‖. The major components contributing to their uncertainties were the amount of sulfur in the test sample and the method precision, based on the equation to calculate the measurand from the intermediate values. Consequently, the concen-tration of sulfur in the used CRM ERM – EF 213 (certified value 9.1 0.8 mg kg-1) with it expanded uncertainty was 9.84.0 mg kg-1, which was acceptable to support the successful application of the analytical method. The method precision gave the largest contribution to the overall combined uncertainty of sulfur concentration.