pH optical sensors based on sol–gels: Chemical doping versus covalent immobilization

Lobnik, Aleksandra; Oehme, Ines; Murkovic, Ivana; Wolfbeis, Otto S.

doi:10.1016/s0003-2670(97)00708-3

Cited by 211 publications

(134 citation statements)

References 17 publications

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“…19 The experimentally recorded response times are also faster than for optodes based on plasticized PVC as a substrate, which require up to minutes to establish an equilibrium. [20][21][22] On the other hand, optodes using a hydrogel matrix as the substrate show response times that are below 30 s; however, indicator leaching is clearly observed under continuous flow operation.…”

Section: Response Time To Ph Changesmentioning

confidence: 99%

“…Wolfbeis and coworkers compared the leaching of aminofluorescein (AF) from sol-gel layers fabricated by chemical doping and by covalent immobilization. 19 In the case of chemical doping, some leaching of AF from the sensing layer is observed over prolonged periods. In contrast, in the case of covalent immobilization, AF did not leach any further after a 10 -20 h continuous exposure to buffer flow.…”

Section: Signal Repeatability and Stabilitymentioning

confidence: 99%

See 1 more Smart Citation

A Fast-Response pH Optode Based on a Fluoroionophore Immobilized to a Mesoporous Silica Thin Film

et al. 2010

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Section: Response Time To Ph Changesmentioning

confidence: 99%

Section: Signal Repeatability and Stabilitymentioning

confidence: 99%

A Fast-Response pH Optode Based on a Fluoroionophore Immobilized to a Mesoporous Silica Thin Film

et al. 2010

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“…Through these reactions, the pHsensitive materials possess sensing ability to detect the pH of solutions. The pH indicators were chemically or physically immobilized into a solid support [17][18][19][20]. Silica is considered as one of the best solid substrate used to host the pH indicators.…”

Section: Isrn Analytical Chemistrymentioning

confidence: 99%

Sol-Gel Thin Films Immobilized with Bromocresol Purple pH-Sensitive Indicator in Presence of Surfactants

El‐Ashgar

El-Basioni

El‐Nahhal

et al. 2012

ISRN Analytical Chemistry

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Preparation of transparent sol-gel thin film immobilized with bromocresol purple (BCP) pH-sensitive indicator was made via the acid catalyzed sol-gel reaction of tetraethylorthosilicate and the bromocresol purple indicator (BCP). Different surfactants include cationic cetyl trimethyl ammonium bromide (CTAB), anionic sodium dodecyl sulfate (SDS), and nonionic Triton X-100 (TX-100) were used to improve the mesostructure of the host material and to increase its porosity. The color change behavior of the immobilized bromocresol purple indicator affected significantly in presence of SDS comparing with its free counterpart in aqueous solution. In presence of CTAB and Triton-X 100, the immobilized bromocresol purple indicator shows similar behavior as its free counterpart in aqueous solution. The BCP retains its structure during the sol-gel reactions in terms of response to pH. Different parameters including concentration of indicator and surfactant, temperature, number of layers, response time, life time, and the number of measurements were investigated. The pK a values of the different prepared BCP immobilized thin films were determined. The BCP thin film sensor showed stability, repeatability, reproducibility, fast response, and long life time behavior. The polarized light microscopy indicated that the bromocresol purple indicator molecules are distributed uniformly within the host silica network.

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“…Wolfbeis and co-workers reported the immobilization of ruthenium complexes on ormosils films and their use for O 2 sensing. 150 Using a different approach Rosenzweig and co-workers 161 reported the immobilization of liposomes that encapsulate fluorescent dyes in a sol-gel film (Fig. 9).…”

Section: Sol-gel Materialsmentioning

confidence: 99%

Design of Fluorescent Materials for Chemical Sensing

2007

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There is an enormous demand for chemical sensors for many areas and disciplines. High sensitivity and ease of operation are two main issues for sensor development. Fluorescence techniques can easily fulfill these requirements and therefore fluorescent-based sensors appear as one of the most promising candidates for chemical sensing. However, the development of sensors is not trivial; material science, molecular recognition and device implementation are some of the aspects that play a role in the design of sensors. The development of fluorescent sensing materials is increasingly captivating the attention of the scientists because its implementation as a truly sensory system is straightforward. This critical review shows the use of polymers, sol-gels, mesoporous materials, surfactant aggregates, quantum dots, and glass or gold surfaces, combined with different chemical approaches for the development of fluorescent sensing materials. Representative examples have been selected and they are commented here.

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pH optical sensors based on sol–gels: Chemical doping versus covalent immobilization

Cited by 211 publications

References 17 publications

A Fast-Response pH Optode Based on a Fluoroionophore Immobilized to a Mesoporous Silica Thin Film

A Fast-Response pH Optode Based on a Fluoroionophore Immobilized to a Mesoporous Silica Thin Film

Sol-Gel Thin Films Immobilized with Bromocresol Purple pH-Sensitive Indicator in Presence of Surfactants

Design of Fluorescent Materials for Chemical Sensing

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