Method and apparatus for vitrification of water or moisture-containing test samples, particularly biological samples

Abstract

To vitrify a sample, for example a biological sample which has a high water content, without the formation of ice crystals, the sample (10) is placed in a closed test chamber (11) having a chamber outlet (35). The chamber (11), with the sample therein, is filled with a primary fluid without cooling the sample to freezing temperature. This primary fluid may be an alcohol. The sample is vitrified by applying a high-pressure cryogenic fluid against the sample at a substantial pressure. The step of maintaining the pressure is accomplished, in accordance with the invention, by maintaining the outlet (35) from the chamber (11) at least essentially closed by a closing element, typically a valve (41), until the pressure within the sample chamber (11) has reached a predetermined value. The primary fluid may be a portion of the cryogenic fluid itself, for example heated, or even cooled, to an appropriate temperature which, however, will not cause the sample to freeze. Automatic interlocks (63; 32) can be provided to ensure that the high-pressure cryogenic fluid is applied only after the chamber has been filled and pressurized by the primary fluid. A pressure rise to 2,100 bar, and more, in 20 milliseconds can be obtaining, resulting in a high cooling rate of at least 20,000.degree. C. per second, which cools the sample. Liquid nitrogen is a suitable cryogenic fluid.

Dependencies are inferred from the claim text.