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Opis: Potentiometric determination of penicillamine (pen) is described based on a batch experiment and flow-injection analysis (FIA) using a chemical sensor with AgI-based membrane. The membrane was prepared by pressing silver salts (AgI, Ag2S) and powdered Teflon. This membrane was incorporated in a multipurpose electrode body for batch measurements, and in a tabular flow-through sensor body for FIA measurements. For batch measurements, the equilibrium potentials recorded with continuous addition of standard penicillamine solution were considered in relation to ▫$lg(c_pen/mol L^-1)$▫. Linear response with slope of 60 mV was obtained in the concentration range from 2.5 x ▫$10^5$▫ mol ▫$L^1$▫ to 1.8 x ▫$10^-2$▫mol ▫$L-1$▫. In using the tubular sensor with a membrane of the same coposition for FIA measurements, the linear response with slope of 59 mV was recorded in the concentration range from 1 x ▫$10^4$▫ mol ▫$L^1$▫ to 1 x ▫$10^-1$▫ mol ▫$L^-1$▫. The response of the applied chemical sensor to penicillamine (designated also as RSH) is explained by the formation of sparingly soluble RSAg in the reaction solution and/or the exposed surface of the sensor. The solubility product ▫$K_s(RSAg)$▫ was determined using experimental values recorded both by batch measurements and by the continuous-flow experiment. The mean value obtained by different measurements and using a membrane of the same composition is ▫$K_s(RSAg)$▫ = (1.4+-0.1) x ▫$10^-20$▫ mol ▫$L-2$▫).
Ključne besede: analytical chemistry, batch potentiometry, flow-injection analysis, membrane electrode, tubular sensors, penicillamine
Objavljeno v DKUM: 05.07.2017; Ogledov: 1316; Prenosov: 90
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