We have compared the effect of increasing optode separation (range 0.7-5.5 cm) on the sensitivity of near infrared spectroscopy (NIRS) to discrete reductions in scalp and cerebral oxygenation in 10 healthy men (mean age 32, range 26-39 yr) using multichannel NIRS. During cerebral oligaemia (a mean reduction in middle cerebral artery flow velocity of 47%) induced by a mean reduction in end-tidal...

A yet unexplained drift of (some) oxygen optodes during storage/transport and thus significant deviations from factory/laboratory calibrations have been a major handicap for autonomous oxygen observations. Optode drift appears to be systematic and is predominantly a slope effect due to reduced oxygen sensitivity. A small contribution comes from a reduced luminophore lifetime, which causes a sma...

Real-time in-situ temperature detection is essential in many applications. In this paper, a simple and robust optode, which uses Ruthenium (II) complex as a temperature indicator, has been developed for rapid and sensitive temperature detection in small volume samples (<5 μL). Transmission of excitation light and collection and transmission of fluorescence are performed by a homemade single-mul...

This study investigated the effect of hydrostatic pressure of up to 6000 dbar onAanderaa and Sea-Bird oxygen optodes both in the laboratory and in the field. The overall pressure response is a reduction in theO2 reading by 3%–4% per 1000 dbar, which is closely linear with pressure and increases with temperature. Closer inspection reveals two superimposed processes with an opposite effect: an O2...

A novel optical sensor has been proposed for sensitive determination of bismuth ion basedon immobilization of 4-(4-nitrophenylazo)-1-naphthol on a triacetylcellulose membrane.Chemical binding of bismuth ions in solution with a 4-(4-nitrophenylazo)-1-naphtholimmobilized on the triacetylcelluse surface could be monitored spectrophotometrically. Theoptode shows excellent response over wide concent...

An inexpensive and fast vanadium [(IV), (V)] speciation method was performed by using optical chemical sensor that incorporates lipophilized calmagite (Cal) with cetyl pyridinium chloride (CPC) as a suitable ligand on triacetylcellulose membrane in aqueous solutions prior to UV-Vis spectrometric determination. Absorbance decrease of the optode in pH 6 at 490 nm depended on the V(V) ion concentr...

This work details the use of a 2-component optode membrane which is capable of generating three distinct colours in the presence of Cu(2+) and Co(2+) ions. It has been found that the ionic liquid (IL) trihexyltetradecylphosphonium dicyanamide [P(6,6,6,14)][DCA] can act as plasticizer, ligand and transducer dye when used in poly(vinyl chloride) (PVC) membranes, which significantly simplifies the...

A microsize biocomputing system based on enzyme logic processing biochemical signals was developed. Optical transduction of pH signals generated in situ by the enzyme OR logic gate was achieved with the use of a single optode microparticle.

a novel optical sensor has been proposed for sensitive determination of bismuth ion basedon immobilization of 4-(4-nitrophenylazo)-1-naphthol on a triacetylcellulose membrane.chemical binding of bismuth ions in solution with a 4-(4-nitrophenylazo)-1-naphtholimmobilized on the triacetylcelluse surface could be monitored spectrophotometrically. theoptode shows excellent response over wide concent...