Fully automated photocolorimetric method for dissolved silica in oil well water rich in sulfide and bicarbonate.
A fully automated photocolorimetric method for dissolved silica in oil well water rich in sulfide and bicarbonate is proposed; the method is based on yellow silicomolybdic heteropolyacid. To eliminate the interference of sulfide a treatment with bromate is utilized. The analytical range is 1-30 mg L(-1); with the automatically performed dilution it extends up to 300 mg L(-1), RSD 5.5%.
Fundamental principles of titrations with potassium bromate
Abstract Based on the results of researches into the chemistry and analytical uses of interhalogen compounds and of halogen ions of one positive charge, the fundamental principles of bromatometry are discussed by the authors. It is pointed out that in redox titrations with potassium bromate, in place of bromate or bromic acid, actually elementary bromine, or bromine chloride, or bromine chloride and elementary chlorine act as agents. Thus, bromine and bromine chloride form a complex with the halide content (bromide and chloride, respectively) of the solution to be titrated. The redox potential and polarity (electrophilic nature) of this complex can be controlled by varying the halide concentration. By clearing up the fundamental principles it has been possible to determine precisely the optimum experimental conditions of the various bromatometric procedures.
Multiple potentiometric system for continuous determination of chloride, fluoride, nitrate and ammonia in natural waters
ZusammenfassungEin Durchflußsystem wurde entwickelt zur gleichzeitigen Bestimmung von Chlorid (30–150 ppm), Fluorid (0,08-0,4 ppm), Nitrat (5–20 ppm) und Ammoniak (0,05-0,5 ppm). Folgende Elektroden wurden eingesetzt: Festkörperelektroden für Chlorid und Fluorid, PVC-Membranelektrode für Nitrat und die ORION 95-10 Gassensor-Elektrode für Ammoniak. Der Luft-segmentierte Probestrom wird vor Eintritt in die Meßzellen mit geeigneten Pufferlösungen gemischt. Die mittlere Genauigkeit beträgt ±10%.SummaryA flow-through system for the simultaneous determination of chloride (30–150 ppm), fluoride (0.08-0.4 ppm), nitrate (5–20 ppm) and ammonia (0.05-0.5 ppm) in water was developed. Solid-state chloride and fluoride electrodes, a nitrate PVC membrane electrode with solid silver contact and a gassensing ammonia ORION 95-10 electrode were employed. The air-segmented sample stream is mixed with appropriate buffering solutions before entering the measuring cells. Mean accuracy of the determinations is usually better than ± 10%.