Volume 2, Issue 10 (November 2005)
Improvements in the Determination of Fluorine in Fuel and Lubricants by Oxidative Combustion and Ion-Selective Electrode Detection
Oxidative combustion combined with ion-selective electrode detection is one of several techniques available for the analysis of fluorine in fuels and lubricants to the petroleum and petrochemical industry. This technique was first developed in the mid-1990s to provide an alternative to the widely used Wickbold method, which is very time consuming and extremely hazardous. The early designs were marginally successful due to the lack of sensitivity and stability, the use of large volumes of solvents, inconsistent delivery of fluids, plugging of catch and hold valves, numerous sources of contamination, and long analysis times. The design has been refined to enhance the sensitivity, stability, and accuracy of the fluoride determination. Enhancements include improved ion-specific electrodes with increased sensitivity, the use of circulating baths to stabilize temperature fluctuations, improved sample introduction and flow systems, and redesigned electronic circuitry.