Development of an automatic static volumetric method based on loop injection

Abstract

A prototype of an automatic static volumetric method based on the injection of a pure compound by means of a loop instead of a manual syringe was constructed, fitting for both laboratory use and field applications. The crucial point, the evaluation of the loop volumes, was solved developing two techniques allowing traceability to SI units. Gas mixtures of nitrogen monoxide (NO) in nitrogen in the 10−9 V/V range and carbon monoxide (CO) in air in the 10−6 V/V range were generated and successfully compared to other primary calibration techniques. Relative expanded uncertainties (k=2) of 1.1% (compared to 0.8% of the manual static volumetric method [1]) for NO gas mixtures and 0.3% CO gas mixtures were estimated.