@prefix cpm: . @prefix dc: . @prefix dcat: . @prefix dce: . @prefix dct: . @prefix dcterms: . @prefix grg: . @prefix iop: . @prefix ns0: . @prefix ns1: . @prefix owl: . @prefix pav: . @prefix prov: . @prefix puv: . @prefix qudt: . @prefix rdf: . @prefix rdfs: . @prefix reg: . @prefix sdo: . @prefix semapv: . @prefix skos: . @prefix sssom: . @prefix void: . @prefix xsd: . rdf:type sdo:DefinedTerm ; sdo:description "A series of mass spectrometers that monitor real-time levels of volatile organic compound (VOC). A variety of inlet systems are available. Gas samples are directly injected and detected using Proton Transfer Reaction (PTR) ionisation and quadrupole mass spectrometry. During analysis, soft ionisation is realised by proton transfer from H3O+ ions to all compounds with a higher proton affinity than water. Common constituents of air such as N2 , O2 , Ar, CO2 etc. have lower proton affinities than H2O and are therefore not ionised. Ultra-sensitive and compact variants are available. Dection limit: < 1 pptv - 300 pptv. Response time: 100 ms."@en ; sdo:inDefinedTermSet ; sdo:name "Ionicon PTR-QMS series proton transfer reaction mass spectrometer"@en ; sdo:termCode "SDN:L22::TOOL0968" .