| 摘要 |
A system for creating liquid gradients is disclosed, comprising at least two containers that can be manufactured separately, such as by molding plastic. Each container has an outlet near the bottom and an air vent near the top, and the outlets are connected via tubing to a receiving device in which the liquids are mixed. One container has a horizontal cross-section which decreases as a function of vertical position between the top and bottom of the container; the other container has a horizontal cross-section which increases vertically in a complementary manner. The containers preferably are held together by a rack or other means. As the liquids drain from both containers simultaneously, they remain in hydrostatic balance with each other. Since their fluid levels drop at the same rate, the ratio of liquids entering the mixing device will vary in a controlled, desired manner that depends on the shapes of the containers, according to the ratio of the horizontal surfaces areas of the liquids in their containers at any moment. This creates a desired gradient in the receiving device. By using inexpensive, mass-manufactured, disposable plastic containers, this system provides for simple, inexpensive, rapid creation of gradients which are sufficiently precise and reproducible for work such as chromatography, isoelectric focusing, or other types of separation of biological mixtures in a laboratory, using fluid-handling components that do not need to be cleaned or sterilized.
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