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A glass electrode is the most popular electrode in the determination of acidity owing to its high selectivity, reliability and dynamic pH range. However, the disadvantages of glass electrodes, such as high ohmic resistance, the need for an internal solution and the fragility of glass, suggest that other materials might be more suitable. Thus, non-glass hydrogen ion-selective electrodes have been studied by many researchers. Among them, especially, hydrogen ion-selective solvent polymeric membrane electrodes have been studied more than others. The first solvent polymeric membrane pH electrodes containing an ionophore, instead of glass, have been proposed by Ammann et al. and Schulthess et al. 1,2 This electrode has a PVC layer with tridodecylamine used as an ion carrier and an internal filling solution. Later, other researchers continued to study pH sensing materials and the electrode configuration. Thus, other various compounds (aliphatic, heteroaromatic and their derivatives) 3-9 have been studied as carriers of hydrogen ions; various configurations of this hydrogen ion-selective electrode have also been investigated. These compounds yielded a wider applicable pH range and a better selectivity coefficient. The results were particularly good when tertiary amine compounds were applied. Also, there have been developments concerning the configuration of ion-selective electrodes (ISEs). The configurations of ISEs were changed from the traditional barrel configuration 10 to wire-type electrodes. 11-14 These electrodes sometimes exhibit better selectivities than conventional-type electrodes with an internal solution. [15][16][17][18][19][20][21][22] However, the standard potential of coated-wire electrodes is often unstable, varying for one electrode during its lifetime, as well as differing among electrodes of the same type. These systems cannot provide very reproducible potentials due to blocking the electrons between the PVC membrane coating and the metal. 23 Thus, many researchers have utilized an electron conducting polymer layer with an anionic dopant. 24 They made an electroconductive layer on a metal surface by employing the electrochemical method. This layer, such as poly(aniline), poly(pyrrole), or poly(thiophene), increased the adhesion between the metal substrate and a PVC layer containing ionophore, thus enabling anion or electron transfer at the interface. Especially, poly(aniline) is a versatile material and has many different applications. This poly(aniline) film may be used to construct all solid state sensors by taking advantage of the electronic as well as ionic conductivity. 25 In this study, we used poly(aniline), which could act as a solid contact between a pH-selective PVC membrane containing the ion carrier and a metal contact. In this paper, an all solid state potentiometric sensor for hydrogen ion based on poly(aniline), covered with a plastic PVC membrane and activated by N,N,N′,N′-tetrabenzylethanediamine ionophore, is presented and evaluated in the terms of the analytical application. We a...

The use of natural dyes has attracted increasing worldwide attention as the carcinogenicity and environmental pollution problem of synthetic pigments are becomes a great concern. A nontoxic natural dye was fabricated from an extract from Caesalpinia Sappan (sappan wood). Oily natural dye for industrial application was made from extracted sappan wood by using a micro-emulsion method. The absorbance of the dye extracted from sappan wood by distillation was measured with an Ultraviolet/Visible spectrometer. The highest absorbance was obtained from the mordant containing 2 wt% Al. The emulsification conditions were controlled by changing the mixing ratios of TEOS (tetraethyl ortho-silicate), DC3225C (cyclomethicone and dimethicon copolyol) and extracted dye. A W/O (water in oil) type dye was obtained with a TEOS concentration ranging from 19.9 to 50.0 wt% when the DC3225C concentration was fixed to 10 wt%. The W/O type emulsion was verified by optical microscopy. The fabricated dye was applied to colored paper. The applicability of the nontoxic natural dye was verified by analyzing the heavy metals and color fastness of the colored paper.