Towards Realization of Reactive Gas Amount of Substance Standards Through Spectroscopic Measurements

This paper discusses the use of high-precision direct absorption spectroscopy to realize the amount of substance standards for ozone $(\hbox{O}_{3})$, a reactive species which cannot be delivered through traditional gravimetrically based gas cylinder standards. The $\hbox{O}_{3}$ amount of substance is linked to the known concentrations of nitric oxide (NO) and nitrogen dioxide $(\hbox{NO}_{2})$ through a gas-phase titration reaction and spectroscopic measurements using room-temperature pulsed quantum-cascade lasers. Ultimately, this approach will allow the determination of an $\hbox{O}_{3}$ transition line strength linked to the primary gravimetric standards of NO and $\hbox{NO}_{2}$. The line strength can be used in future measurements to determine $\hbox{O}_{3}$ concentrations of unknown samples.