EP0904536A1 - Element capteur et capteur pour determiner des concentrations d'ozone - Google Patents

Element capteur et capteur pour determiner des concentrations d'ozone

Info

Publication number
EP0904536A1
EP0904536A1 EP97923880A EP97923880A EP0904536A1 EP 0904536 A1 EP0904536 A1 EP 0904536A1 EP 97923880 A EP97923880 A EP 97923880A EP 97923880 A EP97923880 A EP 97923880A EP 0904536 A1 EP0904536 A1 EP 0904536A1
Authority
EP
European Patent Office
Prior art keywords
ozone
dye
sensor element
polymer
sensor
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP97923880A
Other languages
German (de)
English (en)
Inventor
Donald Lupo
Gunther Appel
Ivan Cabrera
Ude Scheunemann
Axel Schönfeld
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
CABRERA, IVAN, DR.
LUPO, DONALD, DR.
SCHEUNEMANN, UDE, DR.
Original Assignee
Hoechst Research and Technology Deutschland GmbH and Co KG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Hoechst Research and Technology Deutschland GmbH and Co KG filed Critical Hoechst Research and Technology Deutschland GmbH and Co KG
Publication of EP0904536A1 publication Critical patent/EP0904536A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/75—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated
    • G01N21/77—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated by observing the effect on a chemical indicator
    • G01N21/78—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated by observing the effect on a chemical indicator producing a change of colour
    • G01N21/783—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated by observing the effect on a chemical indicator producing a change of colour for analysing gases
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N31/00—Investigating or analysing non-biological materials by the use of the chemical methods specified in the subgroup; Apparatus specially adapted for such methods
    • G01N31/22—Investigating or analysing non-biological materials by the use of the chemical methods specified in the subgroup; Apparatus specially adapted for such methods using chemical indicators
    • G01N31/223—Investigating or analysing non-biological materials by the use of the chemical methods specified in the subgroup; Apparatus specially adapted for such methods using chemical indicators for investigating presence of specific gases or aerosols
    • G01N31/225—Investigating or analysing non-biological materials by the use of the chemical methods specified in the subgroup; Apparatus specially adapted for such methods using chemical indicators for investigating presence of specific gases or aerosols for oxygen, e.g. including dissolved oxygen

Definitions

  • the invention relates to a sensor element for determining ozone concentrations and to a sensor which contains at least one of these sensor elements.
  • conductivity sensors based on Sn0 2 can be used to detect ozone, as disclosed, for example, in EP-A-0 31 1 439.
  • the electrical resistance changes due to chemisorption of the ozone on the SnO 2 surface.
  • a disadvantage of this analysis method is the cross sensitivity to almost all oxidative gases, as well as the strong temperature sensitivity of these sensors, which have to be heated to approx. 400 ° C.
  • ozone can be determined spectroscopically on the basis of its absorption at 253.7 nm (VDI guideline: VDI 2468; VDI manual, keeping the air clean, volume 5).
  • VDI guideline VDI 2468; VDI manual, keeping the air clean, volume 5.
  • the disadvantage of this analysis method is the cross sensitivity to hydrocarbons, which also absorb in this frequency range. It is therefore customary to carry out a so-called zero-air measurement in a parallel measurement in a second measurement channel. H. to carry out an absorption measurement on an otherwise identical gas sample which was only selectively freed from the ozone. With the help of this reference measurement, the proportion of cross-sensitive gases can be determined and eliminated. Because of the necessity to always have to carry out a reference measurement, such a measuring device is complex, expensive, sensitive and voluminous.
  • ozone can be determined gravimetrically by selectively binding it to a polymer layer located on a quartz crystal.
  • the adsorption causes an increase in mass, which can be measured by changing the resonance frequency of the quartz crystal.
  • One of the disadvantages of this method is the sensitivity to external interference, especially mechanical shocks.
  • ozone can be detected colorimetrically with a sulfophthaleinf arbstof f.
  • a disadvantage of this measuring system is that the sulfophthalein is only effective in its alkaline form, i.e. H. that acidic ozone-containing air cannot be demonstrated that the dye has to be impregnated on a powder (e.g. silica gel) and that a concentration can only be determined by comparison with a calibrated color scale.
  • This system also ages in air, so that it has to be filled with protective gas between measurements.
  • ozone can be colorimetrically measured in an indigo dye (Tekh. Misul (1988), 25 (2), 59-60) or Acid Chrome Violet K (Ozone: Sei. Eng. (1989), 1 1 (2), 209- 1 5) containing solution can be determined.
  • indigo dye Tekh. Misul (1988), 25 (2), 59-60
  • Acid Chrome Violet K Ozone: Sei. Eng. (1989), 1 1 (2), 209- 1 5 5
  • the disadvantage here is that the measurements must be carried out in a liquid medium, which makes the devices difficult to handle.
  • these systems show a strong cross-sensitivity to other contaminants in the solvent.
  • the object of the present invention was therefore to provide a new, simple, sensitive, inexpensive and compact sensor element and a sensor for determining ozone concentrations which do not have the disadvantages known from the prior art.
  • a sensor element for determining ozone concentrations which is characterized in that it contains at least one dye (chromophore), preferably in solid form, which has conjugated double bonds and which is contained in a polymer layer which has at least one polymer , wherein preferably at least one of the conjugated double bonds is olefinic.
  • chromophore preferably in solid form, which has conjugated double bonds and which is contained in a polymer layer which has at least one polymer , wherein preferably at least one of the conjugated double bonds is olefinic.
  • dye-containing polymers compared to e.g. pure dyes is that the sensitivity to the effects of ozone can be improved or adapted to the requirements. It has been found that by introducing the dye into polymers it is possible to produce layers which on the one hand contain sufficiently high amounts of dye and on the other hand have the necessary permeability for ozone so that the dye molecules within the layer can be reached by ozone.
  • dye-containing polymers compared to, for example, pure dyes is that they are generally easier to process. This is a great advantage if special sensitive readout methods are to be used that place special demands on a layer containing dye, such as special geometric shapes, a layer thickness that must be strictly adhered to, uniformity, absence of light scattering centers and transparency.
  • the sensor according to the invention contains at least one sensor element according to the invention and at least one readout system into which at least one sensor element is integrated.
  • dye-containing polymers are those polymers in which a dye group is attached as a side group to a polymer chain or is located in the main chain of the polymer.
  • the dye can also be dispersed or dissolved in a polymer or in a polymer mixture.
  • the choice of the suitable polymer or the polymer mixture depends on the special requirements.
  • the selection criteria result e.g. from the required solubility of the dye used in the polymer, from the required permeability to ozone, or from the desired temperature stability, mechanical strength and from the required optical properties.
  • the dye-containing polymers change their optical properties in the presence of ozone and allow a quantitative determination of ozone simply by measuring these changes.
  • Mixtures can also be used when using dye-containing polymers of these can be used with other polymers that do not necessarily also contain a chromophore. This makes it possible, for example, to specifically influence the system's absorbance and its mechanical and elastic properties and the degree of crystallization as well as the permeation properties.
  • polymers examples include polyimides, polysiloxanes, polyesters, polyacrylates, polymethacrylates and polyolefins.
  • the invention is not restricted to these polymers.
  • polymers are suitable which have an average molecular weight of 500 to 5,000,000, preferably 10,000 to 500,000, in particular 10,000 to 200,000.
  • plasticizers it may be advantageous to add plasticizers to the dye-containing polymer in order to improve the mechanical properties and permeation behavior, or else to improve the solubility of the dye in the polymer, in the event that the dye is dissolved in the polymer is introduced.
  • All plasticizers used in plastics are suitable as plasticizers, e.g. Phthalates and cresols, the vapor pressure of which is sufficiently low that no significant evaporation from the polymer occurs, and the solubility of which can have a positive effect on the polymer properties.
  • dyes are suitable whose absorption maximum is in the range from 300 nm to 1200 nm, preferably from 350 nm to 700 nm, in particular from 400 nm to 500 nm.
  • a preferred sensor element contains the dye-containing polymer as one of its components or even consists entirely of it.
  • the shape of the polymer and the type of further constituents which may be used depend, inter alia, on how the change in the optical properties under the action of ozone is to be measured.
  • the sensor element can consist entirely of the dye-containing polymer if, for example, a molded body suitable for the intended use, e.g. a film, a fiber or a body with another suitable geometric shape is produced. Production methods suitable for this are known in principle to the person skilled in the art. For example, casting processes from solution, injection molding, extrusion and spinning processes can be used.
  • the dye-containing polymer is part of the sensor element
  • further constituents are in particular carrier materials for the dye-containing polymer.
  • carrier materials for the dye-containing polymer.
  • plates, foils, fibers or other shaped bodies can be used as supports. These can consist of glass, plastic, metal and / or other transparent, reflective or light-scattering carrier materials. In some cases it can be advantageous to provide the carriers with dielectric layers.
  • the supports are coated with the dye-containing polymer.
  • the supports can be provided with other porous coatings beforehand.
  • These porous coatings can contain, for example, particles of titanium dioxide, silicon dioxide or other materials that are suitable optical Properties and have a high specific, open-pore surface.
  • the carriers can be coated in different ways. Suitable processes for this are known to the person skilled in the art. For the production of extremely thin and even layers, e.g. the Langmuir-Blodgett technique is particularly suitable. However, adsorption layers can also be produced by immersing the support in a solution of the dye-containing polymer. Other suitable processes are dip and flow coating, lamination, knife coating and printing, with screen printing and spray coating in particular being mentioned here.
  • the thickness of the applied layer of the dye-containing polymer is preferably between 2 nm and 500 ⁇ m, particularly preferably in the range from 10 nm to 20 ⁇ m and in particular in the range from 20 nm to 5 ⁇ m.
  • the sensor element according to the invention can, for example, flow in a flow cell with a defined volume flow of ozone-containing air or simply be exposed to the ozone-containing air.
  • the dyes in the sensor element change their optical properties in the presence of ozone.
  • the change can e.g. can be detected by determining the optical absorption. How to proceed is known in principle to the person skilled in the art. This can e.g. happen that the sensor element is irradiated by light, the wavelength of which is in the range of dye absorption.
  • the change in the absorption behavior due to the effect of ozone can then be measured by determining the change in intensity of the light passing through.
  • the invention consequently also relates to a method for determining ozone concentrations using at least one according to the invention Sensor element, which is characterized in that the concentration is determined by changing the optical properties, preferably the absorption.
  • an optical arrangement is selected for the measurement, which determines a change in light that is reflected on the sensor element.
  • a reflective plate e.g. of silicon
  • the thickness of this layer is dimensioned such that interference amplification occurs for a certain range of the angle of incidence of the light impinging on the layer.
  • Such an arrangement typically uses monochromatic, linearly polarized light. This provides a particularly sensitive measurement of the change in optical properties due to the influence of ozone. The person skilled in the art knows how such a measuring arrangement is to be carried out in detail.
  • the change in the optical properties can be determined on the basis of the attenuation of evanescent waves from optical fibers.
  • the sensor element is designed in the form of a planar, a stripe-shaped or a fibrous optical waveguide, in which the otherwise usually present waveguide sheath is completely or partially removed and replaced by the dye-containing polymer, so that evanescent waves reach the area of the dye from the waveguide core and can be weakened. If light is now conducted in the waveguide, the wavelength of which lies in the region of the dye absorption, a change in the dye properties has an effect on the waveguide attenuation and can be detected easily and sensitively.
  • the sensor element according to the invention usually contains a thin metal layer, for example made of gold or silver, which in turn is provided with a layer of the dye-containing polymer.
  • a thin metal layer for example made of gold or silver
  • the dye-containing polymer under defined conditions, which depend on the detailed design of the arrangement, surface plasmons can be excited in the metal layer, which have an effect, for example, in that a light beam impinging on the sensor element is reflected with a significantly reduced intensity, part of the energy of the impinging light beam being used Excitation of the surface plasmons is used.
  • the conditions under which this is the case are sensitively influenced by the dye properties on the metal layer and serve as an easily determinable and sensitive measure of their change.
  • a measure of the ozone concentration in the air to which the sensor element was exposed is obtained from the change in the optical properties of the dye-containing polymer, which can be determined by continuous measurements or, for example, by two measurements in succession.
  • a glass plate (25 mm x 75 mm, 1 mm thick) is coated on both sides in the same way as in Example 1 and dried in the drying cabinet at approx. 80 ° C. for about 15 minutes.
  • the glass plate is then brought into a measuring chamber which is provided with two opposite windows for the transmission of light and is located in an optical measuring arrangement for determining the absorption spectrum.
  • Air flows through the chamber with ozone.
  • the air is mixed with ozone by irradiating the air with a low-pressure mercury lamp before the air enters the measuring chamber.
  • the ozone concentration in the measuring chamber is determined using an ozone analyzer from Horiba and is 0.7 ppm. After the ozone begins to act on the sensor element in the measuring chamber, the dye absorption decreases significantly. At a wavelength of 470 nm, the initial rate for the decrease is approximately 0.6% per minute.
  • the flask is provided with a drying tube and the reaction mixture is stirred at 22 ° C for 18 hours.
  • the reaction mixture is then refluxed for 6 hours and then cooled to 22 ° C.
  • the dark red solution is added dropwise with stirring to a solution of 800 ml of methanol and 2 ml of 37% HCl.
  • the polymeric product separates out as a red oil.
  • the product is taken up in diethyl ether and introduced into 800 ml of methanol.
  • the resulting suspension is centrifuged. 3.31 g of product are obtained.
  • the chromophore content is determined by UV / VIS measurements and is 1 8% by weight.
  • the polymer produced is dissolved in cyclohexanone, the concentration being 72 mg / ml.
  • the solution is spun onto cleaned glass substrates (microscope slides) with a size of 37.5 mm x 25 mm at a speed of 100 revolutions per minute.
  • the films are then freed from solvent residues by heating on a hot plate at approx. 100 ° C.
  • a support coated in this way is mounted in the test chamber of a spectrophotometer (Perkin-Elmer Lambda 9) in the measuring beam. Is in the reference beam uncoated carrier mounted.
  • the measuring chamber is flushed with ozone-enriched air, with an estimated concentration of approx. 2 ppm.
  • the absorption spectrum of the polymer films is measured before exposure to ozone and repeatedly during exposure to ozone. A significant decrease in the absorbance of the polymers under the influence of ozone can be found within minutes.
  • the absorption spectra are shown in Fig. 1.
  • the chamber is ventilated and the flow of ozone is interrupted. Without the influence of ozone, no decrease in absorption by light irradiation can be observed. Similarly, no change in the rate of degradation can be observed when the sample is exposed to ozone under radiation or in the dark.
  • a support coated according to Example 3 at 1000 revolutions per minute is mounted in the measuring beam of the sample chamber of the spectrophotometer.
  • the absorbance at the absorption maximum of the chromophore at 433 nm is constantly measured under the influence of ozone at a concentration of 75 ppb on average.
  • the decrease in absorbance at 433 nm is shown in FIG. 2. A decrease in absorption can be clearly demonstrated within less than 2 minutes.
  • the films are then freed from solvent residues by heating on a hot plate at approx. 100 ° C.
  • a coated carrier is mounted in the measuring beam of the sample chamber of the spectrophotometer.
  • the absorbance at the absorption maximum of the chromophore at 536 nm is constantly measured under the influence of ozone at a concentration of 800 ppb on average.
  • SY409 ® and SY430 ® are two different phenylmethyl silicone resins from Wacker that are used as polymers. With this mixture, a squeegee film is produced on a glass plate (25 mm x 75 mm, 1 mm thick) with a wet film thickness of approx. 10 ⁇ m. The coated glass plate is placed on a hot plate at a temperature of 70 ° C. for 5 minutes. After this, a uniform dye-polymer film is obtained on the glass plate.
  • the glass plate is placed in a measuring chamber similar to that in Example 2, with the difference that the light transmission at a wavelength of 450 nm can be continuously recorded by a compensation recorder.
  • the measuring chamber is flushed with ozone-free air for a few minutes.
  • the measuring chamber is filled with air containing ozone for approx. 55 minutes (Ozone concentration between 0.6 ppm and 0.7 ppm) rinsed.
  • the chamber is then flushed with ozone-free air for about 35 minutes and then flushed again with ozone-mixed air (ozone concentration 0.7 ppm) for about 25 minutes.
  • FIG. 4 shows as a plotter diagram the time course of the light transmission and the ozone concentration in the measuring chamber.
  • absorption (absorption (in%) 100 - transmission) at times of ozone exposure. It can also be seen that the absorption does not change when the measuring chamber is flushed with ozone-free air.
  • Example 8 The glass plates in the measuring chamber are then subjected to measurements one after the other in accordance with Example 6, in which the measuring chamber is flushed with ozone-mixed air of different concentrations.
  • the mean ozone concentrations in the first case are 0.17 ppm and in the second case 0.26 ppm. Due to the effects of ozone with different concentrations, there are different initial rates for the decrease in dye absorption (measured at 450 nm). In the first case, the initial rate of 0.23% per minute and in the second case 0.32% per minute in each case based on the light intensity I 0 prior to the glass plate without absorption.
  • Example 8 Example 8
  • the coated glass plate is then irradiated for 30 seconds with UV light from a medium-pressure mercury lamp to crosslink the layer. During the irradiation, the glass plate is flushed with gaseous nitrogen in order to keep atmospheric oxygen away. The result is a uniform film on the glass plate, which shows no signs of crystallization of the dye.
  • the glass plate is placed in a measuring chamber as in Example 6.
  • the transmission at a wavelength of 450 nm is continuously recorded by a compensation recorder.
  • the measuring chamber is flushed with ozone-free air for a few minutes.
  • the measuring chamber is then flushed several times with ozone-mixed air with different ozone concentrations between 0.1 ppm and 0.5 ppm. In between, rinsing is carried out with ozone-free air.

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  • Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Physics & Mathematics (AREA)
  • General Health & Medical Sciences (AREA)
  • Pathology (AREA)
  • Immunology (AREA)
  • General Physics & Mathematics (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • Biophysics (AREA)
  • Molecular Biology (AREA)
  • Dispersion Chemistry (AREA)
  • Emergency Medicine (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Plasma & Fusion (AREA)
  • Investigating Or Analysing Materials By Optical Means (AREA)
  • Investigating Or Analysing Materials By The Use Of Chemical Reactions (AREA)
  • Investigating Or Analyzing Non-Biological Materials By The Use Of Chemical Means (AREA)

Abstract

L'invention concerne un élément capteur pour déterminer des concentrations d'ozone, lequel est caractérisé en ce qu'il renferme au moins un colorant présentant des liaisons doubles conjuguées et contenu dans une couche polymère possédant au moins un polymère. L'invention concerne également un capteur comportant au moins un élément capteur de ce type, ainsi qu'un procédé pour déterminer les concentrations d'ozone.
EP97923880A 1996-05-13 1997-05-13 Element capteur et capteur pour determiner des concentrations d'ozone Withdrawn EP0904536A1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE19619226 1996-05-13
DE1996119226 DE19619226A1 (de) 1996-05-13 1996-05-13 Sensorelement und Sensor zur Bestimmung von Ozonkonzentrationen
PCT/EP1997/002440 WO1997043636A1 (fr) 1996-05-13 1997-05-13 Element capteur et capteur pour determiner des concentrations d'ozone

Publications (1)

Publication Number Publication Date
EP0904536A1 true EP0904536A1 (fr) 1999-03-31

Family

ID=7794172

Family Applications (1)

Application Number Title Priority Date Filing Date
EP97923880A Withdrawn EP0904536A1 (fr) 1996-05-13 1997-05-13 Element capteur et capteur pour determiner des concentrations d'ozone

Country Status (4)

Country Link
EP (1) EP0904536A1 (fr)
JP (1) JP2000510590A (fr)
DE (1) DE19619226A1 (fr)
WO (1) WO1997043636A1 (fr)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3943008B2 (ja) * 2002-08-28 2007-07-11 日本電信電話株式会社 オゾンガスの検知素子および検出装置ならびに検出方法
CN100460856C (zh) * 2002-08-28 2009-02-11 日本电信电话株式会社 臭氧气敏元件
JP2008086950A (ja) * 2006-10-04 2008-04-17 Nippon Telegr & Teleph Corp <Ntt> オゾンガスフィルタ
JP4880425B2 (ja) * 2006-11-07 2012-02-22 日本電信電話株式会社 オゾン検知素子
CA3074622C (fr) * 2017-09-29 2024-01-02 Raul Gotor Detection de contamination par des hydrocarbures dans le sol et l'eau

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3881869A (en) * 1973-07-02 1975-05-06 Beckman Instruments Inc Chemiluminescent detection of ozone
JPH0695082B2 (ja) * 1987-10-08 1994-11-24 新コスモス電機株式会社 吸引式オゾンガス検知器
US4859607A (en) * 1989-01-17 1989-08-22 Kansas State University Research Foundation Colorimetric detector for ozone and method of preparation
DE4001031C2 (de) * 1990-01-16 1994-01-05 Fraunhofer Ges Forschung Mittel zur kolorimetrischen Bestimmung von Methylmethansulfonat
US5212250A (en) * 1991-09-17 1993-05-18 Hoechst Celanese Corp. Poly(maleic anhydride) copolymers with side chains exhibiting nonlinear optical response
DE19512739A1 (de) * 1995-04-05 1996-10-10 Hoechst Ag Schwingquarzsensor

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9743636A1 *

Also Published As

Publication number Publication date
JP2000510590A (ja) 2000-08-15
WO1997043636A1 (fr) 1997-11-20
DE19619226A1 (de) 1997-11-20

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