Design of anion-selective membranes for clinically relevant sensors

Abstract

Requirements for the applicability of anion-selective electrodes in clinical analysis are discussed in terms of selectivity, response time, lifetime and stability. Basically, classical anion-exchangers, electrically charged carriers and electrically neutral carriers may be used as anion-selective components in solvent polymeric membranes. While classical ion-exchanger-based membrane electrodes are only of limited practical relevance, sensors containing ion carriers seem to bear a broad potential with regard to the feasibility of realizing the required properties. The control of the selectivity determining properties of electrically neutral tin organic anion carriers probably allows the development of sufficiently selective membranes for the assay of clinically relevant anions. Furthermore, the incorporation of membrane technology into the design of such carrier membranes may lead to fully optimized sensors.

Sequential Injection Analysis of Ampicillin in Pharmaceuticals by Using Potentiometric Detectors Based on PVC and Sol-Gel Membranes

“…Regarding the Hofmeister selectivity pattern of the classical liquid ion-exchanger, the developed PVC and sol-gel membranes exhibited different selectivity sequences from that one as previously demonstrated when the same metalloporphyrin had been used to construct other anion selective membrane electrodes, namely carboxylic ions [2,4,27] obtained. Being much more hydrophilic in nature, the sol-gel membrane was less affected by lypophilic anions such as SCN -which confirm the notion that interferent action can be reduced by eliminating the plasticizer in the polymeric membrane [29]. On the other hand, the fact that the interferent action of the salicilate diminished when the sol-gel membrane electrode is used, could led to eliminate significant error for measurement of ampicillin in biological fluid samples from patients who have ingested aspirin.…”

Electromotive behaviour of anion selective membranes with triorganotin acetates as ionophores and nucleophiles as additives

“…Nevertheless, the results presented here are of general importance as to the mode of action of the triorganotin carriers involved. The incorporation of nucleophiles into the membrane is based on the fact that the tetrahedral tin centre of triorganotin compounds with suitable electronegative substituents X may be attacked by nucleophiles (normally sample anions) resulting in a pentacoordinated species and finally in a neutral carrier being different from the one originally added to the membrane phase (SN2 mechanism) [10,12]. The nucleophiles added may therefore lead to a preformation of a large concentration of unloaded neutral carrier having a constitution which is rather independent of the sample anions.…”

Sol‐Gel Derived Potentiometric Sensor for Determination of Vanadyl Ions

“…In addition to the inherent three dimensional network structures, the matrices do not have plasticizers as constituents. It is believed that the enhanced vanadyl selectivity is related to the latter [35,37]. Table 4 lists linear range, detection limit, lifetime, response time and slope of some of the vanadyl-selective electrodes against proposed sol-gel derived vanadyl-selective electrodes for comparative purposes [14 -18].…”