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Enjoying our new Karl Fischer Oven for ASTM D6304, Procedure B

Enjoying our new Karl Fischer Oven for ASTM D6304, Procedure B - By Ben Hartman, President of MRT Laboratories

MRT is enjoying our new Karl Fischer oven, the Metrohm 885 (see photo). Eighteen samples on the autosampler tray and ideal for our needs when customers require the most accurate measurement of water contamination in parts per million of heavily additized lubricants. Our main of use of this instrument is for testing engine oils. At MRT we also administer the Crackle test, but it simply isn’t as accurate, and this new instrument is perfect for us. We should have purchased this a long time ago! 


We are adding ASTM D6304, Procedure B to our testing capabilities when previously we offered only Procedure A. With this new KF oven we can now run Procedure B for superior accuracy of measuring water contamination in fluids whose additive chemistry interferes with the direct sample injection Karl Fischer titration process. Engine oils commonly contain higher concentrations of either calcium or boron. Both elements will interfere with direct KF titration. As a reminder, the KF titration generates iodine from iodide and water in a sample is titrated by reacting with the iodine in the titration solution and the concentration of water is measured by correlating the current required to generate iodine from iodide. Certain heavily additized lubricants increase iodine consumption in the titration which creates a higher testing result for H2O in a sample. ASTM D6304 Procedure B, or the indirect procedure, titrates water vapor being distilled from the oil sample, so iodine consumption is unaffected by oil additives.


Thank you to Metrohm for this great instrument!

Thu Jan 13 2022, by Ben Hartman, CLS
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