Sensing concentration ranges

However, it is not obvious that when we work with multivariate data, our training set must span the concentration ranges of interest in a multivariate (as opposed to univariate) way. It is not sufficient to create a series of samples where each component is varied individually while all other components are held constant. Our training set must contain data on samples where all of the various components (remember to understand "components" in the broadest sense) vary simultaneously and independently. More about this shortly. 

The ion sensing scheme based on the use of potential-sensitive or polarity-sensitive dyes (PSDs) was extended to other anions. Both the clinically significant chloride ion124 and the environmentally important nitrate anion125 can be sensed in the desired concentration ranges. Such sensors have the unique advantage of having a virtually pH-insensitive response. 

The direct potentiometric determination (using a cation-selective membrane electrode) of procaine and some physiologically active amines in pharmaceuticals has been reported [70]. The sensing membrane was formed from PVC plasticized with dibutyl phthalate, and contained 0.1 mM trioctyloxybenzene-sulfonic acid in dibutyl phthalate. The reference solution was a mixture of 1 mM solution of the organic base and hydrochloric acid. Response was found to be linear over a wide concentration range, and the method was highly selective. 

Normally, it makes little sense to apply such systems in lab-scale ozonation experiments, since the high mass transfer rates are only achieved at high gas flow rates which because of the typical operation characteristics of EDOGs accordingly means low ozone gas concentrations. An appropriate field of application was, however, presented in the study of Sunder and Hem pel (1996) who operated a tube-reactor for the ozonation of small concentrations of perchloroethylene. An injector nozzle coupled with the highly efficient Aquatector ozone-absorption unit was installed in front of the tube-reactor. Both the gas and liquid were partially recycled in this system. According to the authors more than 90 % of the ozone produced was absorbed in demineralized water and dissolved ozone concentrations ranged up to 100 pmol L-1 (cL = 5 mg L-1, T= 20 °C). 

Analyte Type Concentration Range Major Interferences, or Active Enzyme Reaction Sensing Electrode... 

An electrode for the determination of L-aspaitate is constructed by chemical immobilization of L-aspartase on an ammonia gas-sensing probe. The electrode response is linear in the concentration range 0.7-20 mM with aslope of—59 mV/ decade. The biosensor is stable for more than 20 days (299). 

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