A coated-wire ion-selective electrode (ISE) based on cyclam (1,4,8,11-tetraazacyclotetradecane) as a neutral carrier in a polyvinyl chloride (PVC) matrix was fabricated for the determination of Ag(I) ions. The coated-wire ISE exhibited a linear Nernstian response over the range 1 × 10 -1 to 1 × 10 -7 M with a slope of 59 ± 2 mV per decade change and a detection limit of 5 × 10 -8 M. The ISE shows a greater preference for Ag over other cations with good precision. The electrode was selective towards Ag(I) ions in the presence of 13 different metal ions tested. The selectivity coefficients (Kij) were determined for Na(I), K(I), Mg(II), Ca(II), Ba(II), Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Pb(II) and Hg(II). The selectivity coefficients of these cations are in the range of 10 -4 to 10 -2 . This ISE was used for the determination of free silver and total silver in electroplating bath solutions, additives and brighteners.

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Aims:To create a normative data for lea grating (LG) in the Indian population and to compare LG with Cardiff Acuity Card (CAC).Settings and Design:Normative Data was acquired from normal children between 6 months-3 years coming to the ‘Immunisation Clinic’ and ‘Well-Baby Clinic’ at a Civil Hospital. To compare LG with CAC, normal and amblyopic children between 6 months-3 years were evaluated,Materials and Methods:Monocular and binocular visual acuity (VA) was measured using LG and then CAC. VA and time taken to perform the test were compared.Statistical Analysis Used:Pearson's Correlation Coefficient to compare VA and Student paired t-test (significance P<0.005) to compare time.Results:Two standard deviations of VA of 100 normal children overlapped with that published by Lea. Of the 30 amblyopic children aged 18.32 ± 10.5 months (2-36), 18 were females. VA was 0.95 ± 0.3 logMAR (0.7–1.2) and 1.0 ± 0.6 logMAR (0.5–2.1) binocularly and 1.32 ± 0.08 logMAR (0.2-0.6) and 1.15 ± 0.15 logMAR (0.88-1.48) monocularly on CAC and LG respectively. Pearson's correlation coefficient was 0.98 and 0.63 for binocular and monocular assessment respectively. Time taken to perform LG monocularly and binocularly was significantly less (P<0.001) than CAC.Conclusion:Normative data acquired in Indian pre-verbal children is similar to that published by Lea. Though VA by CAC is better than LG, the two tests are comparable.

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Tetraazacyclotetradecane, tetratosyltetraaza 12C4, and tritosyltriaza 9C3 have been explored as electroactive materials for preparing coated wire ion-selective electrodes (CWISEs) for Cr(III) ions. The best performance was observed for the membrane comprising electroactive material (tetratosyltetraaza 12C4), plasticizer (dibutyl phthalate), and poly(vinyl chloride) in the optimum ratio 5:60:35 (w/w). Linear Nernstian response for this electrode was obtained over the total Cr(III) concentration range of 1 x 10(-1) to 1 x 10(-7) M in 0.05 M NH4NO3 medium, with a slope of 20 +/- 1 mV per decade change. The working pH range of the electrode was 1.8-5.5. Selectivity coefficients of some mono, divalent, and trivalent metal ions were determined. Analyses of electroplating bath solutions, chromating, and effluent samples have been carried out using this CWISE and the results are found to be comparable with those obtained by using conventional methods or by AAS.

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Stability constants of complexes of Ag(I) and Cu(II) perchlorates and nitrates with some macrocyclic compounds in 90 and 75% (v/v) DMSO 1 water and 75% (v/v) DMF 1 water media have been determined by potentiometry. Silver and copper wires, and Coated Wire Ion Selective Electrodes (CWISE) were used as indicator electrodes. It was observed that complexation is stronger when the salt is present as a perchlorate than when it is as a nitrate. For both cations the stability constant values in 75% (v/v) DMF 1 water were somewhat higher than in 75% (v/v) DMSO. The macrocyclic effect due to cyclization of linear amine tosylates has been observed. Competitive potentiometry has been utilized to compare some of the results.

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