Sensitivity and Working Range of Backside Calibration Potentiometry
MetadataShow full item record
A new direction in potentiometric sensing, termed backside calibration potentiometry, was recently introduced. It makes use of the fact that the stir effect disappears in the absence of an ion-ionophore complex concentration gradient across supported liquid ion-selective membranes. This method is especially suitable for measurements in which recalibration in the sample is not feasible, such as in remote monitoring applications. Here, a theoretical model is established to predict the workingconcentration range of the method. Lead(II)-selective Celgard membranes were used here with H+ as the dominant interfering ions. The emf difference for stirred and unstirred solutions was measured, and the magnitude of this emf change as a function of the sample Pb2+ concentration was found to exhibit a bell shape that spans ~3 orders of magnitude. The concentration of interfering ions and the selectivity of the membrane were demonstrated to be important factors that affect the working range. Smaller ratios of primary ion concentrations at both aqueous sides of the membrane gave smaller emf differencevalues, and emf changes could still be observed with a logarithmic concentration ratio of 0.05. All experimental results correlated satisfactorily with the theoretical model.
Open access to this article was made available 12 months after publication via the website of the American Chemical Society. http://acswebcontent.acs.org/home.html
The website for Analytical Chemistry is available at:
Showing items related by title, author, creator and subject.
Saeed, Asim (2012)Among different types of membrane modules used for cross flow filtration processes, Spiral Wound Module (SWM) dominates in the area of Ultra Filtration (UF), Nano Filtration (NF) and RO (Reverse Osmosis) due to high packing ...
Nasir, Subriyer (2007)Reverse Osmosis (RO) is widely accepted as an alternative method to produce freshwater from different feed water sources. This technology competitively substitutes the thermal processes in the near future because of several ...
Berwick, Lyndon (2009)The analytical capacity of MSSV pyrolysis has been used to extend the structural characterisation of aquatic natural organic matter (NOM). NOM can contribute to various potable water issues and is present in high ...