Method and apparatus for measuring reactant concentrations and quantities

摘要

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