Dyeless optical detection of ammonia in the gas phase using pH-responsive polymers with reflectometric interference spectroscopy

Rathgeb, F.; Gauglitz, Günter

doi:10.1016/s0003-2670(98)00372-9

Cited by 11 publications

(9 citation statements)

References 24 publications

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“…The correlation of the polymer swellings and thus the sensor signals with the analyte concentration is often described as a Henry sorption [37], a Langmuir type sorption [38] or a combination of both types [39,40,41]. For all polymers under investigation the sorption of R134a is best described as a linear Henry type sorption.…”

Section: Calibration Curvesmentioning

confidence: 99%

Quantification of the refrigerants R22 and R134a in mixtures by means of different polymers and reflectometric interference spectroscopy

Dieterle

Belge

Betsch

et al. 2002

Analytical and Bioanalytical Chemistry

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The aim of this study was the quantification of vapors of the ozone-depleting refrigerant R22 in the presence of its most important substitute R134a, by the use of the reflectometric interference spectroscopy and polymers as sensitive layers. First, the sorption characteristic of different types of polymers exposed to the vapors of the two analytes was investigated. Then, binary mixtures of the two refrigerants were measured with an array set-up on the basis of six polymer sensors. The measurements were evaluated by the use of neural networks, whereby low limits of detection of 0.45 percentage volume (vol. %)for R22 and 1.45 vol. % for R134a could be established. Additionally, one polar polymer and one microporous polymer were selected for the measurements with a low-cost set-up. The quantification of R22 in the presence of R134a with this low-cost set-up was possible with a limit of detection of 0.44 vol. %, which would enable a fast and economical monitoring at recycling stations.

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Section: Calibration Curvesmentioning

confidence: 99%

Quantification of the refrigerants R22 and R134a in mixtures by means of different polymers and reflectometric interference spectroscopy

Dieterle

Belge

Betsch

et al. 2002

Analytical and Bioanalytical Chemistry

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“…The synthesis of the pH-responsive polymer polymethylcarboxypropylsiloxane (Posimca50) had been described previously [8]. The preparation of the polymer layers for the ellipsometric and FT-IR measurements was done as follows: 40 µl of a Posimca50 solution in acetone (20 wt%) were spin-coated for 40 s at 5000 rpm onto silizium wafer substrate.…”

Section: Ph-sensitive Polymer Layersmentioning

confidence: 99%

“…The swelling effect of a pH-responsive polymer is accompanied by five interdependent chemical equilibria, which are illustrated in [8]. In humid air (r.h.>0%), a certain amount of H 2 O molecules will be dissolved in the polymer phase.…”

Section: Characterisation Of the Sorption Processmentioning

confidence: 99%

“…[9,10,11], it was furthermore observed that a change of the local ion-concentration in the polymer is accompanied by a sharp refractive index step [8]. Since Reflectometric Interference Spectroscopy (RIfS), a well investigated and established method in our group [2,8], detects the change of the optical path length ∆(nd), the question occurred, whether the change of the physical thickness ∆d or the change of the refractive index ∆n is the dominating measurand. Therefore the Posimca50 layer was characterised by IR-spectroscopy as well as with spectroscopic ellipsometry.…”

Section: Spectroscopic Ellipsometry and Infrared Spectroscopymentioning

confidence: 99%

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Characterization of thin polymer and biopolymer layers by ellipsometry and evanescent field technology

Mutschler

Kieser

Frank

et al. 2002

Analytical and Bioanalytical Chemistry

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The characterization of sensitive layers is the prerequisite for the optimization of chemical and biochemical sensors. The application of SE (Spectral Ellipsometry) and SPR (Surface Plasmon Resonance) as methods of characterization of such sensitive layers is discussed. In combination with infrared spectroscopy, the properties of polymer networks, micro-porous polymers, liquid crystals, and biomimetic polymers can be examined regarding their applicability for optical sensing. Apart from the basic principles regarding the characterization approaches, applications in the area of environmental sensing, optimization of hydrogel layers for antigen/antibody interaction, and discrimination of analytes in homologous series of alcohols are discussed. The effects of analytes on the phase transition in combination with disordering of liquid crystals are given.

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“…It can rapidly obtain information on the rate and extent of adsorption, enabling the determination of the association/dissociation kinetics and the affinity constants of specific ligand/ligate interactions. Therefore, the RIfS has been used as transducer in biomolecular interaction analyses for the detection of triazine herbicides in river water, hydrocarbon in air, ammonia in gas phase, protein interactions in covalently attached dextran layers, and in clinic detection of HbsAGb25–29 Recently, the application of RIfS for the evaluation of the biocompatibility of biomaterials has been described in 30, 31…”

Section: Introductionmentioning

confidence: 99%

An effective method for quantitative evaluation of proteins adsorbed on biomaterial surfaces

Xiao

Huang

Qian

et al. 2003

J Biomedical Materials Res

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An effective method for the quantitative evaluation of proteins adsorbed on biomaterial surfaces has been developed. First, the kinetic behavior of a range of human fibrinogen (Fib) adsorbed onto polystyrene (PS) films was investigated by using a reflectometry interference spectroscopy setup. The specific molecular number of adsorbed proteins, N(p,) was then defined. According to the definition, the numbers of Fib molecules adsorbed on PS films were calculated. An atomic force microscope (AFM) was used to scan the lateral distribution of the Fib molecules adsorbed on the PS films. From the AFM images, the practical specific molecular numbers were obtained by direct counting of the molecules. In order that the adsorbed number of Fib molecules on a unit area of the PS films could be counted easily, the solution concentration of proteins was reduced to 5 ag/mL (10(-18)g/mL). There was good consistency between the numbers calculated with the formula defined by us and the numbers counted from AFM images. Therefore, the results of the present study prove the validity of our definition of the specific molecular number of adsorbed proteins and the effectiveness of the reflectometry interference spectroscopy-based method for quantitative evaluation of adsorptive proteins.

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Dyeless optical detection of ammonia in the gas phase using pH-responsive polymers with reflectometric interference spectroscopy

Cited by 11 publications

References 24 publications

Quantification of the refrigerants R22 and R134a in mixtures by means of different polymers and reflectometric interference spectroscopy

Quantification of the refrigerants R22 and R134a in mixtures by means of different polymers and reflectometric interference spectroscopy

Characterization of thin polymer and biopolymer layers by ellipsometry and evanescent field technology

An effective method for quantitative evaluation of proteins adsorbed on biomaterial surfaces

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