Inductively-coupled plasma volume in
inductively-coupled plasma optical emission spectroscopy where the analytically-relevant light emission begins to be observed.
Source:
PAC, 2021, 93, 647. 'Glossary of methods and terms used in analytical spectroscopy (IUPAC Recommendations 2019)' on page 722 (https://doi.org/10.1515/pac-2019-0203)