@prefix cpm: . @prefix dc: . @prefix dcat: . @prefix dce: . @prefix dct: . @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 semapv: . @prefix skos: . @prefix sssom: . @prefix void: . skos:member . skos:related . skos:related . skos:narrower . skos:altLabel "UoS NOC pH sensor" , "UoS NOC pH sensor"@en ; skos:broader , ; skos:definition "A National Oceanography Centre custom designed bench-top sensor for shipboard autonomous seawater pH measurements, developed in collaboration with the University of Southampton. The seawater sample and thymol blue indicator solution are pumped by two syringe pumps and mixed in the flow cell in a static mixer before entering the absorption cell. The fluid distribution is controlled by four micro-inert valves. A three-wavelength LED light source transmits light through the absorption cell which is detected by a HR4000 spectrometer. The measurements are made close to in situ temperature (plus 0.2 degrees celsius) by placement of the microfluidic flow cell in the sampling chamber which has continuous access to the ship's underway seawater supply. The LED's wavelengths are 435 nm (25 nm full width half maximum (FWHM)), 596 nm (15 nm FWHM) and 750 nm (30 nm FWHM)."@en ; skos:inScheme ; skos:notation "SDN:L22::TOOL1129" ; skos:note "accepted"@en ; skos:prefLabel "National Oceanography Centre Colorimetric Microfluidic pH sensor"@en ; skos:related . skos:narrower . skos:narrower . skos:narrower .