Following the trend towards smaller channel inner diameter for better separation performance and shorter channel length for shorter transport time, a modular construction of a miniaturized 'total chemical analysis system' is proposed. The theoretical performances of such systems based on flow injection analysis, chromatography and electrophoresis, are compared with those of existing chemical sensors and analysis systems.

Miniaturized total chemical analysis systems: A novel concept for chemical sensing

Carrier-Based Ion-Selective Electrodes and Bulk Optodes. 1. General Characteristics.

Polymers in sensor applications

A novel cysteine-selective electrode based on lead phthalocyanine (PbPc) as ionophore is described. The electrode was prepared by incorporating PbPc into a plasticized poly(vinyl chloride) (PVC) membrane, which was directly coated on the surface of a graphite electrode. This electrode shows high selectivity for the response to cysteine, as compared with many common inorganic anions, salicylate, and other kinds of amino acids. The influence of membrane composition, pH, and the effect of lipophilic cationic and anionic additives on the response characteristics of the electrode were investigated. The resulting sensor demonstrates nernstian response over a wide linear range of cysteine concentration (1 × 10-6 to 5 × 10-2 M). The electrode has a fast response time, micromolar detection limit (∼1 × 10-6 M), and good long-term stability (more than 1 month). The prepared electrode was used for determination of cysteine in a synthetic human serum sample, and very good recovery results were obtained over a wide con...

Lead Phthalocyanine as a Selective Carrier for Preparation of a Cysteine-Selective Electrode

To a certain extent, all cellular, physiological, and pathological phenomena that occur in cells are accompanied by ionic changes. The development of techniques allowing the measurement of such ion activities has contributed substantially to our understanding of normal and abnormal cellular function. Digital video microscopy, confocal laser scanning microscopy, and more recently multiphoton microscopy have allowed the precise spatial analysis of intracellular ion activity at the subcellular level in addition to measurement of its concentration. It is well known that Ca2+ regulates numerous physiological cellular phenomena as a second messenger as well as triggering pathological events such as cell injury and death. A number of methods have been developed to measure intracellular Ca2+. In this review, we summarize the advantages and pitfalls of a variety of Ca2+ indicators used in both optical and nonoptical techniques employed for measuring intracellular Ca2+ concentration.

https://www.physiology.org/doi/pdf/10.1152/physrev.1999.79.4.1089

Measurement of Intracellular Calcium

The influence of ionic sites on the behavior of charged carrier-based ion-selective liquid membrane electrodes is described by theory and experiments for cation- and for anion-selective electrodes. The cation exchanger potassium tetrakis[3,5-bis-(trifluoromethyl)phenyl]borate proved to be a beneficial additive for nitrite-selective electrodes. On the other hand, the anion exchanger tridodecylmethylammonium chloride improved the potentiometric properties of cation-selective electrodes. By the incorporation of a defined amount of these sites, the selectivity was enhanced, the emf functions became theoretical, the electrode resistance was lowered, and the long-term stability improved. The optimal molar ratio of additive to ionophore was in the range of 0.3-0.6 for the ionophores studied

Ionic additives for ion-selective electrodes based on electrically charged carriers

Formation du complexe 1:3 Ca ++ /N,N,N',N'-tetracyclohexyl-3-oxapentanediamide La limite de detection de la fonction reponse de l'electrode est environ 100 pM Ca 2+

Neutral carrier based calcium(2+)-selective electrode with detection limit in the sub-nanomolar range

A hydrogen ion-selective liquid-membrane electrode based on tri-n-dodecylamine as neutral carrier

Le chlorure de tri-n-octyl etain induit une selectivite anionique dans les membranes et se comporte comme un ionophore vis-a-vis des anions. La formation des complexes ionophore-anion est confirmee par spectrometrie RMN- 13 C et 119 Sn, par osmometrie de pression de vapeur et par des essais de transport

Tin organic compounds as neutral carriers for anion selective electrodes

Donnees sur une nouvelle serie d'ionophores pour ions hydrogene, utilisables avec des electrodes de pHmetrie, a membrane polymere

E. Pretsch

Papers

Ionic additives for ion-selective electrodes based on electrically charged carriers

Neutral carrier based calcium(2+)-selective electrode with detection limit in the sub-nanomolar range

A hydrogen ion-selective liquid-membrane electrode based on tri-n-dodecylamine as neutral carrier

Tin organic compounds as neutral carriers for anion selective electrodes

Design of neutral hydrogen ion carriers for solvent polymeric membrane electrodes of selected pH range