The Use of a Custom-Built Coulometric Karl Fischer Instrument for the Determination of Water Content in Chocolate
2015
Clippard, Carrie M. | Nichisti, Joseph C. | Kreuter, Rodney A. | Chohan, Balwant S. | Sykes, Danny G.
A Karl Fischer (KF) coulometric titration method was designed and optimized for the quantitative determination of water in chocolate. A number of essential KF experimental parameters were investigated and assessed, including a study of polar extraction solvents, extraction times, interfering side reactions, and a comparison of pyridine-free KF coulometric reagents. The optimized protocol was found to be applicable to a wide variety of chocolate samples. Typical coulometric titration times for the chocolate samples were between 1 and 5 min, translating to water contents from 0.18 to 0.38 % w/w. With this contribution, the quantification of water in chocolate using KF titration methods is now a simple, safe, and reliable process, comparable in terms of precision and accuracy to any commercially available KF coulometric apparatus.
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