Flow injection determination of iodide ion in a photographic developing solution using iodide ion-selective electrode detector.
A potentiometric flow injection determination method for iodide ion in a photographic developing solution was proposed by utilizing a flow-through type iodide ion-selective electrode detector. The sensing membrane of the electrode was Ag(2)S-AgI membrane. The response of the electrode detector as a peak-shape signal was obtained for injected iodide ion in a photographic developing solution. A linear relationship in the subnernstian zone was found to exist between peak height and the concentration of the iodide ion in a photographic developing solution in a concentration range from 0 to 6.0x10(-5) mol l(-1). The relative standard deviation for ten injections of 2x10(-5) mol l(-1) iodide ion in a photographic developing solution was 0.96% and the sampling rate was approximately 12-13 samples h(-1). The iodide ion could be determined under coexisting of an organic reducing reagent and inorganic electrolytes of high concentration in a photographic developing solution sample solution by the present method.
Inhibition kinetic determination of trace amount of iodide by the spectrophotometric method with rhodamine B.
Trace iodide was determined by inhibition kinetic method, which based on its inhibition effects on the reaction between rhodamine B (RhB) and KBrO(3) in H(2)SO(4) medium in 45+/-0.5 degrees C for 15 min. The signal difference (DeltaA, DeltaF) between inhibited reaction and non-inhibited reaction is linear with the concentration of iodide. The linear range were 2.0-6.0 and 1.0-6.0 ng mL(-1) and the detection limit were 0.06 and 0.07 ng mL(-1), respectively. The method has been applied satisfactorily to the determination of iodide in kelp.
Spectrophotometric determination of low levels of anionic surfactants in water by solvent extraction in a flow injection system
An approach to automation, in routine control, for the determination of anionic surfactants in river water and treatment plant water in the concentration range 0.04–3.5 µg ml–1 using a continuous solvent extraction process with flow injection analysis, is described. The method is based on an ion-pair extraction reaction with Methylene Blue in chloroform. The separation of both phases is accomplished by means of a membrane phase separator and detection is based on injection of the coloured organic phase into a chloroform stream which passes to the detector. Methanol was added to the organic phase in order to enhance the extraction process and to ensure efficient extraction of the various anionic surfactants. A number of anionic species and non-ionic surfactants have been tested as possible interferents. The results obtained for samples of river water show good agreement with those obtained with the Methylene Blue batch method.