Generate VOC calibration gas standard from a liquid

Available from Alytech, the LiqMix Cascade is an accurate calibration tool designed for the automated generation of customised standard gas from pure liquids or liquid mixtures for the purpose of multipoint calibration of VOC gas analysers, GC or GC/MS, and to validate the precision and reliability of GC sample introduction systems. Gas standards such as BTEX in air, other hydrocarbons, siloxanes, ethanol and phenol, humidity standards can be produced on-site from % down to ppb levels accurately with high repeatability and traceability.

The liquid components are tared in advance using a laboratory balance, loaded in the reservoir and pressurised with inert gas like helium or nitrogen. Precisely controlled liquid micro flow is delivered into a vaporiser where it evaporates into a flow of a carrier gas (air, N2, H2, He, … ). To achieve very low concentrations a portion of homogenous gas/vapour mixture is delivered to the second dilution stage, so-called Cascade, where it is further diluted to desired concentration. All interconnections and outlet line of LiqMix are heated in order to maintain the vapours in gas phase and thus avoiding re-condensation up to the delivery point.

Easy to handle, dedicated AlyTech software controls the operation, manages mass flow controllers, its calibration tables, performs automatic calculation of liquid and span gas flows, to achieve desired concentration of analytes even for very complex multicomponent mixtures. Following highest metrology requirements the instrument not only accurately prepares the gas mixtures, but it also automatically calculates and reports maximum relative uncertainty for every delivered concentration.

Rich remote control functionalities of the software and automated programmed sequences enable full automation by synchronising the calibrator with a gas chromatograph, pre-concentrator, spectrometer, gas analyser or other system.