MEASUREMENTS OF SMALL AMOUNTS OF H$sub 2$O IN D$sub 2$O BY NEAR-INFRARED ABSORPTION SPECTROSCOPY

The literature on the near-infrared and infrared absorption spectra of liquid H/sub 2/O and D/sub 2/O as well as other literature related to the determination of small amounts of one in the presence of the other was reviewed. Nearinfrared absorption techniques appear to be very convenient, rapid, and almost ideally suited for the determination of H/sub 2/O in the concentration range from 0 to 10% in D/sub 2/O. The absorption spectra of H/sub 2/O, D/sub 2/ O, (HDO), and of mixtures of H/sub 2/O in D/sub 2/O were obtained using a Cary Model l4 PM Recording Spectrophotometer. As expected. the H/sub 2/O was found to undergo very rapid and almost complete exchange to HDO, especially at relatively low H/sub 2/O concentrations. In agreement with some previously reported French and Japanese work, a relatively intense and very useful absorption band for HDO has been found at l.668 mu , and it is used for the determination. By the use of the procedure described. 0.5, 2, 4, and 7 wt.% H/sub 2/O in D/sub 2/O can be determined with respective approximate relative standard deviations of 7, 2, 1, and 0.7% when 1-cm absorption cells are used in conjunction with a pure D/sub 2/O reference liquid. (auth