| 摘要 |
A method and apparatus is provided for determining the concentration or quantity of enzyme molecules, microorganisms or substrate molecules by monitoring directly the concentration and/or the quantity of vaporous by-product produced from the selective reaction of the molecule catalyzed with a known amount of substrate or of an enzyme or a microorganism. The apparatus comprises a membrane permeable to the vaporous product or substrate, a known amount of microorganism or an enzyme adjacent to the membrane, means for introducing a liquid sample into contact with the microorganism or enzyme within a small volume adjacent the membrane and means for measuring the amount of vaporous by-product passing through the membrane. A mass spectrometer located adjacent the membrane surface is suitable for measuring the amount of vaporous product or substrate passing through the membrane. The process is conducted by first calibrating the apparatus with a known concentration of substrate or of enzyme, and thereafter contacting a sample containing an unknown concentration of enzyme or microorganism with the substrates, or substrate with the enzyme or microorganism.
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