@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 in situ total hydrogen scale pH sensors used to measure freshwater or seawater pH. They are designed to provide autonomous pH time-series data for scientific research. The sensors operate by mixing sample with an indicator dye and measuring pH by absorbance. Typical dyes are cresol red for freshwater or m-cresol purple for seawater samples. Light sources and path lengths vary between versions (tungsten, LEDs) Accuracy ranges between -0.003 to + 0.0004 pH units. Precision ranges from +/-0.004 to +/-0.0007 pH units. This code is used where it is not known which version of SAMI-pH model is used."@en ; sdo:inDefinedTermSet ; sdo:name "Sunburst Sensors Submersible Autonomous Moored Instrument pH {SAMI-pH} seawater and freshwater pH sensor series"@en ; sdo:termCode "SDN:L22::TOOL1613" .