Trace concentration calibration standards of acetaldehyde in carbon dioxide are dynamically blended using the FlexStream™ Automated Gas Standards Generator and TraceSource™ Permeation Tubes. Acetaldehyde emitted by the permeation tube is added directly to a controlled flow of purified or beverage grade carbon dioxide to form the mixture. Mixture concentration is adjusted by varying to carbon dioxide flow. User may achieve concentrations from over 400 ppb down to 25 ppb using a single permeation tube. Lower concentrations, or variable concentration in constant flow, are available using optional secondary dilution. The standard additions technique is used to compensate for residual acetaldehyde in the carbon dioxide. Mixtures concentrations are traceable to NIST through physical standards.
Acetaldehyde is a key component causing ‘off taste’ and ‘off odor’ problems in carbonated beverages and is routinely monitored to ensure concentrations below 200ppb. Trace concentration mixtures are generally not stable in storage. The dynamic blending method using permeation tubes avoids that problem and insures reliable standards.