Preparation of optical sensor doped

Preparation of Optical Sensor Doped in PMMA Matrix... 

The introduction of 2-[4-(dimethylamino)phenylazo]benzoic acid into a silica sol allows the preparation of pH-sensitive doped coatings upon glass substrates. The behavior of this system was evaluated as the function of pH changes in liquid and gas media68. Optical absorption and sensitivity against pH were monitored by Vis spectroscopy. Chemical and mechanical stability tests carried out with coatings demonstrated that they were resistant enough to be use in sensor devices for pH measurements in laboratories. 

In the preparation of the optical sensor doped in sol-gel, the following three steps were carried out ... 

Serum samples of 1.0 mL are collected from various real patients and centrifuged for 15 min at 4000 r/min to remove proteins. After the preparation of the serum samples the optical sensor doped in sol-gel matrix is immersed in each sample solution and the luminescence spectrum of the optical sensor is measured before and after the addition of serum sample. The optical sensor must be rinsed after each measurement by solvent [55] (Figure 14.12). 

Table 14.2 Determination of Ramipril in serum and pharmaceutical preparations using Sm +-DC optical sensor doped in sol-gel matrix.

Dodecyl acrylate microspheres, crosslinked with hexanediol diacrylate, were prepared by emulsion polymerisation and characterised by scanning electron microscopy, particle size measurement, and differential scanning calorimetry. The microspheres were doped with 9-(diethylamino)-5-(octadecanoylimino)-5H-benzo(alpha)phenoxazine (ETH 5294), a chromoionophore whose fluorescence emission spectrum is sensitive to pH. These microspheres adsorb anions selectively according to their lipophilicity, and therefore can be used as anion-selective optical sensors. The responses of the microspheres to chloride, nitrate and perchlorate ions were reported. 27 refs. 

The Metoclopramide hydrochloride concentration was determined by the optical sensor europium doped in the sol-gel matrix. The absorption and emission spectra of Metoclopramide hydrochloride and Europium were measured in sol-gel matrix. The method depends on the enhancement of the intensity of the emission spectrum of Eu doped in sol-gel especially at 617 nm band. The mechanism depends on the energy transfer from triplet energy state of Metoclopramide hydrochloride to the excited energy state of Eu. In comparison with other spectrofluorimetric techniques, this method is simple, relatively interference free from coexisting substances and can successfully be applied to the determination of Metoclopramide hydrochloride in pharmaceutical preparations and in serum samples the data are summarized in Table 14.3 [53]. 

Gas sensors based on sol-gel films were widely investigated for the detection of O2 [169-171], CO2, CO, H2 [172], H2S, I2, NH3, NO, and NO2 and were summarized in Refs [173,174]. Fiber-optic sensors for humidity based on evanescent wave scattering and absorption were prepared by doping the sol-gel coating with methylene blue [175]. Sensors were also developed for the determination of... 

A relatively wide variety of organic cations may be used as counter cations of the TCNQ simple salts for the preparation of conductive LB films. For example, the LB films of octadecyltrimethylphosphonium [56], octadecyidimethylsulphonium [57] and octadecyl-methylethylsulphonium [58] salts showed a relatively high optical conductivity after iodine doping. Quinoli-nium salts [59-61] and dithiolium salts [62] were also subjected to LB film formation. Attempts to construct gas sensors have been reported [63-65]. The sodium salt of TCNQ was incorporated in a calixarene LB film. The in-plane conductivity of the LB film of NaTCNQ/... 

---