Apparatus and method for sampling and IR-spectroscopic analysis of high-pu rity, hygroscopic liquids

摘要

A sample tube is fist filled with liquid. Dry nitrogen is then passed through the supply lines. In a third step liquid from the mains supple is passed into tube and from there through the supply lines and out of the system. In a fourth step tube is again filled with liquid from the main supply. The tube is then ready for the conventional IR spectroscopic analysis. The liquid under test is silicon tetrachloride with a purity of 99.95%, as used in the manufacture of fiber optics. In order to prevent contamination of the sample a four-step purging process is established. Purging cycles are measured in hours and liquid equivalent to about five times the volume of tube is used in the liquid purging cycle. The stainless steel sample tube has a diameter between 1 and 3 cm and a length between 5 and 20 cm. It is closed at either end by calcium fluoride discs having a diameter between 1.5 and 5 cm and a thickness between 0.2 and 1 cm.