Sparingly selective ion-selective electrode arrays for multicomponent analysis

Abstract

Enormous effort has been expendedIn the past toward the development of highly specific Ion-selective electrodes. However, we have further developed the case that the use of an array of sparingly selective electrodes can result In multicomponent analyses that are superior, In many cases, to those obtained when the electrodes are highly specific. The requirement for a successful analysis then shifts from selectivity to stability and reproducible characterization of the sensors.

Calibration procedures for a halide Ion-Selective Electrode array

“…The standard deviation in the measurement of the 5 central points of the experimental design is used as a measure of repeatability to obtain σ(ε a ) 2 [19]. As this is small in this case compared to s(a) 2 , λ is small and the improvement should also be small. In fact, in the present case the improvement is expected to be negligible from a practical point of view, but it seemed of interest to verify the theory anyway.…”

“…An ISE measures solution potential (see for instance [6]) which is related to the free primary ion activity by the Nernst equation (1), but can also be related to the free interfering ion activity by the Nikolskii relation (2) according to the IUPAC recommendations [7].…”

“…(1) (2) where E is the ISE potential versus the reference electrode, A a constant representing the standardisation potential, R the perfect gas constant, T the temperature, F the Faraday constant, a i and z i are the activity and the charge number of the primary ion, a j and z j the activity and the charge number of the j interfering ions, and K i,j is the interference coefficient.…”

“…Otto et al [1] showed that an over-determined approach of the problem for multiple ion determinations is feasible with Ca 2+ , Mg 2+ , Na + , K + . Beebe et al [2][3] stated that using an array of sparingly selective electrodes gives better results than using an array of highly selective electrodes (use of non linear multiple regression, for Na + , K + ). Forster et al [4][5] found that better results are obtained when one sparingly selective electrode is associated with highly selective electrodes to determine a low concentration of one of the cations (Na + , K + , Ca 2+ ) in a medium where other cations are present in a large amount.…”

A computer‐controlled multi‐electrode switch

“…In particular, multi-component analysis using ion-selective electrodes (ISE) as chemical sensors is a rapidly expanding field [1][2][3][4][5][6][7]. The [3,[6][7][8][9].…”