Simple modification of karl-fischer titration method for determination of water content in colored samples

Abstract

The most commonly used technique for water content determination is Karl-Fischer titration with electrometric detection, requiring specialized equipment. When appropriate equipment is not available, the method can be performed through visual detection of a titration endpoint, which does not enable an analysis of colored samples. Here, we developed a method with spectrophotometric detection of a titration endpoint, appropriate for moisture determination of colored samples. The reaction takes place in a sealed 4ml cuvette. Detection is performed at 520nm. Titration endpoint is determined from the graph of absorbance plotted against titration volume. The method has appropriate reproducibility (RSD = 4.3 ), accuracy, and linearity (R 2 = 0.997). © 2012 Eva Tavar et al.