DETERMINATION OF FIXED WATER IN ROCKS BY INFRARED ABSORPTION

An infrared absorption technique has been developed for the quantitative determination of “fixed water” (H2O+) in rocks. Potassium bromide disks containing 2-mg samples are scanned in the 3-μm spectral region and absorption at 2.96 μm is determined. Although the exact nature of this peak is not known, other than that it is caused by an interaction between the potassium bromide and hydroxyl groups and water, it can be used for quantitative analysis. Rock samples, other than those containing significant percentages of clay minerals, can be analyzed with a standard deviation of 0.26%. © 1969, American Chemical Society. All rights reserved.