The Flexstream Gas Standards Generating System dynamically blends calibration gas standards for trace sulfur compounds in food-grade carbon dioxide. Specially designed permeation tubes add low-parts-per-billion (ppb) concentrations of typical sulfur species, including carbonyl sulfide, hydrogen sulfide and mercaptans, directly to a controlled flow of purified, beverage-grade carbon dioxide to create trace concentration calibration standards. The unit compensates for residual background contamination in the matrix gas using the standard additions technique. Calibrations are based on the known difference in the concentration of sulfur-containing compounds due to the addition from the permeation tubes. The FlexStream has a secondary dilution feature that generates parts per trillion concentrations. The unit is suitable for carbon dioxide quality assurance, laboratories, food and beverage processing and pharmaceuticals — Kin-Tek Laboratories, La Marque, Tex.