INSTRUMENT FOR CHEMI-OR BIOLUMINESCENT ANALYSIS

Abstract: An instrument for chemi- or bioluminescent analysis of the concentration of a constituent of a sample gas (G<u1>u) which in a reaction chamber (C) reacts with a liquid reagent (R<u1>u) in a luminescent manner. The liquid reagent (R<u1>u) is ejected into the reaction chamber (C) by ejection means. The sample gas (G<u1>u) can be used as propellant in the ejection means (E) sucking the liquid reagent (R<u1>u) into the propellant and as an aerosol be sprayed into the reaction chamber. Carefully mixed with the sample gas, it generates chemiluminescent radiation (L<u1>u, L<u2>u) in the field of view of a photodetector (D). The propellant (G<u1>u) can also be prepared so that either heating or cooling occurs on expansion in the reaction chamber (C). By providing walls of the reaction chamber with reflecting layers, the main portion of the luminescent radiation reaches the detector (D).

Description: Instrument for Chemi- or Bioluminescent Analysis This invention relates to an instrument for the ge¬ neration and detection of bio- or chemiluminescent radia¬ tion. This is achieved by bringing together in a reaction chamber two or more gaseous or liquid substances into the field of view of a photodetector means; at least two of these substances yield luminescence upon reacting and at least one of them is a gas. For the quantitative analysis of small amounts of gaseous substances several methods are used at present, such as spectrophotometry, fluorimetry, gas-chromatography and galvanometry. All of these require relatively expen¬ sive equipment. Particularly in cases where an accurate determination of very small amounts of i.e. gaseous pollu¬ tants (with hygienic limits set at 1 ppm or lower) is re- quired, the available instrumentstend to be both costly and bulky. Due 'to a growing demand' for a better working environment, a need has long been felt for reliable, simple, cheap and in particular, sensitive measuring devices for the quantitative determination of gaseous or gasborne pollutants with concentrations ranging from 10 ppm down to thousandths of ppm. It is known (i.e. Anal. Chem. , 45, 443A (1973)) tha a large number of gaseous substances can be accurately determined by means of chemiluminescent reactions. Such reactions generate light, the intensity of which is di- rectly proportional to the concentration of the reactant If during the reaction the luminescent reactant is in excess, the light intensity is directly proportional to the concentration of the substance investigated in the sample; thus a simple measurement of light intensity yields an accurate determination of* the sample concentra tion. The radiation can be generated in any of the visib ultraviolet and infrared spectral regions. Generally, a luminescent reactant can be either a s lid, a liquid or a gas. When a gaseous sample reacts wit a liquid reagent, the light generation will be proportio nal to the area of the gas-liquid interface. In a known device this is achieved by adsorbing the reagent on a gel and passing the gaseous sample over the surface of the gel (Geophys. Res. 65, 3975 (I960)). The disadvantage of this method (as that of other devices in which a gaseous sample is bubbled through a liquid reage is the relatively small size of the gas-liquid interface When the objective is to continuously determine a gaseou pollutant such as ozone, continuous blowing of the sampl against the reagent in the gel or bubbling it through th reagent causes the latter to successively change its con centration as a result of evaporation and reaction with the sample, resulting in an unsatisfactory accuracy of t analysis. If both reagent and sample are gaseous a number of known devices are available where both gases mix and rea to yield chemiluminescence. In the British patents 1 341 and 1 353 722 two different reaction chambers are descri in which the gases are mixed in front of a photomultipli These devices can only be used for purely gaseous compo¬ nents. In the American patent 3,998,592 a thermoelectric heat- pump is used for simultaneous heating of the reaction cell and cooling of the photomultiplier. This device is also intended for gaseous components only. Furthermore, the 5 thermoelectric heat-pump pnly yields a certain preset tempe¬ rature difference between the hot and the cold side. As a rule, the photomultiplier has to be cooled further - either directly or by extracting more heat from the hot side of the thermoelectric heat-pump. With some bio- or chemilumi- 10. nescent systems better light yields are obtained at tempera¬ tures below ambient temperature, in such cases the above- mentioned device is not applicable. The present invention relates to an instrument for bio- ' or chemiluminescent analysis without the above- 15 mentioned limitations and in which the concentration of a sample gas is measured in a reaction chamber in the field of view of a photodetector means, reacting in a luminescent manner with a liquid reagent from a reagent container. Said instrument comprises means for ejecting said liquid rea- 20 gent into said reaction chamber in the form of aerosol par¬ ticles and means for prpviding a flow of said sample gas to the reaction chamber. By causing the sample gas flow to be pulsed with arbitrarily presettable pulse duration and intervals, two advantages are gained. On the one hand a 25 higher gas pressure can be used, resulting in a considerab¬ ly higher luminescent intensity and on the other hand, a lower consumption of the reagent occurs due to the inter- mittence. The ejector means may use the sample gas as a propeUant in such a way that the liquid reagent via one 30 or several pipes is arranged to be sucked into the propel- lant jet by the ejection effect an converted into an- aerosol. In some cases, an inert gas may serve as propeUant. By choosing a carrier-gas with a high inversion tempera- 35 ture, such as N 2 , the gas is cooled on expansion outside the ejector. If heating is desired instead, a carrier-gas OMPI ^ " Wi 0 with a low inversion temperature, such as H 2 , can be use The ejector device is preferably arranged to be adj able with respect to the size of the aerosol particles. The latter should of course be as small as possible in o der for the total gas-liquid interface to be as large as -3 possible. A radius of 10 cm for the aerosol particles will give a total surface of 3000 cm 2 for 1 cm3 of liqui Adjustment can be achieved by the positioning of the eje tor tube in the ejector nozzle. It can also be advantageous to design the liquid reagent tube (tubes) entering the ejector (ejector tubes in the form of capillaries, at least in some part of the tube. In this way, the liquid substance will not flow ba beyond the capillary. The time needed for the carrier-ga to suck up liquid from the capillary to the ejector nozz can be made equal to the time needed for the carrier-gas to flush the reaction chamber and the detector window be fore the liquid reaches the ejector and the start of the chemiluminescent reaction. If the light generation in the reaction is weak, th light flux to the detector can be increased by making th walls of the chamber reflecting. The detector is placed the outside of the. window or on a transparent part of th reaction chamber. In order to prolong the usage of the reagent it is advantageous to drain the reagent back into the reagent container by means of an electronically controlled valve This is done as long as the detector does not yield a si nal or if the signal has a lower amplitude than a preset threshold value. Otherwise the reagent is channelled int a container for consumed reagent. One advantage with sai method is that the reproducibility is considerably in¬ creased due to the fact that only fresh reagent will par cipate in the luminescent reaction. If substances occur whose detection is not required but which also yield chemiluminescence with the particul reagent being used, the photodetector unit may be arranged to contain two or more detector elements each of which is supplied with a transmission filter for different wave¬ lengths or wavelength bands. The relation between the sig- nal amplitudes then decides whether the detection should result in an alarm or not. In some cases it can be advantageous to keep the de¬ tector (if arranged within the reaction chamber) or the detector window, free of liquid substances. This can be achieved by means of a gas- or air- curtain. The invention is described in more detail below with reference to the enclosed figures 1-3. Figures 1 and 2 show an embodiment of the invention, of which Fig. 1 shows a block-diagram, while Fig. 2 shows an intersection of an enlarged drawing of the reaction chamber with the ejector device. It also shows a photodetector means mounted onto the reaction chamber. Fig. 3 shows the front view of an ejector device with two ejector tubes. In Fig. 1 a sample G, in the form of ambient air is arranged to be sucked through a filter F by means of a pump P, which subsequently compresses the sample G, in a sample volume V. When a magnetic valve M, opens, the sample (which in the present case is the propeUant gas as well) flows with high speed through a nozzle H (Fig. 2) in the ejector device E and in so doing sucks up reactant R. from the reactant container S-. by means of the ejector effect. The propeUant gas G, then brings the reactant into the gas-jet, here consisting of ambient air. The reactant R-^ is dispersed and is sprayed in the form of an aerosol into the reaction chamber C. The light generated by luminescence partly falls directly L, (Fig. 2) onto the detector unit D • and partly on the reflecting walls. After having been re¬ flected one or more times 2 , the light reaches the de¬ tector D. The walls of the reaction chamber C are coated with a reflecting layer B. The major part of the reagent is led either through a magnetic valve M 2 back to the reagent container S, or in cases when the measured light exceeds a preset threshold value on the signal processing unit A, is led to a container for waste reagent S 2 . The result of the measurement is presented by a display unit N. This measuring sequence is repeated after a predetermined inte val. Fig. 2 shows the reaction chamber C with ejection means E and detector means D. The ejector tube K is adjus able along the length direction to minimize the drop size. The wall T onto which the detector means D is arranged is transparent for the radiation in question. Furthermore, the reaction chamber is provided with drain passages U and W for gas and liquid respectively. Fig. ' 3 is a front view of a possible embodiment of an ejecting means provided with two ejector tubes K. One advantage of the present invention is that it also can be used for gaseous reactants. It can also be used for liquid reactants, provided an inert driver-gas is used. This renders the instrument very flexible. In the case where the carrier-gas sucks in another gas (eventual¬ ly together with a liquid) by means of the ejector effect, said other gas can be samples of ambient air.

Claims: Claims 1. Chemi- or bioluminescent analysis instrument in which two or more gaseous and/or liquid substances (G.. , G , Η._. ) of which at least two are reacting to each other in a luminescent manner and of which at least one is a gaseous substance, said substances are arranged to be brought together in a reaction chamber (c) in the field of view of a photodetector means (D), CHARACTERIZED BY ejector means (E) for bringing said substances (G-. , G , R.. ) together, in which ejector means one or more of said gaseous substances are used as propeUant gas (G 1 ) in such a way that the other gaseous or liquid substances (G , R 1 ), through one or more tubes (K) are sucked into the propel- lant jet and ejected into the reaction chamber and, for liquid sub¬ stances (R 1 ), in the form of aerosol particles mix, and in a lumine¬ scent manner react with the other gaseous or liquid substances (&.,, G„) in the field of view of said photodetector means (D). 2. Instrument according to claim 1, CHARACTERIZED IN that the propeUant gas (G.. ) is arranged to be pulsed with arbitrarily pre- settable pulse intervals, pulse duration and .pressure. 3. Instrument according to claim 1 or claim 2, CHARACTERIZED IN that the propeUant gas (G..) is an inert gas. 4. Instrument according to any one of the preceding claims, CHARACTERIZED IN that the propeUant gas (G 1 ) is cooled on expan¬ sion in the reaction chamber (c). 5. Instrument according to any one of the preceding claims, CHARACTERIZED IN that the propeUant gas (G. ) is heated on expan¬ sion in the reaction chamber (c). 6. Instrument according to any one of the preceding claims, CHARACTERIZED IN that the ejector means (E) is adjustable to mini¬ mize the aerosol particle size. 7. Instrument according to any one of the preceding claims, CHARACTERIZED IN that the ejector tubes (K) opening out into the^ ejector nozzle (E), at least in some part, are designed as capil¬ laries. 8. Instrument according to any one of the preceding claims, CHARACTERIZED IN that the walls of the reaction chamber (c) are made reflective to the luminescent radiation (l> 2 ) > exept for the aerea in front of the photodetector means (D). 9. Instrument according to any one of the preceding claims, CHARACTERIZED IN that the photodetector means (D) comprises two or more detector units, each provided with a transmission filter for a different wavelength band, said detector units being electrically connected to a signal processing means (A). 10. Instrument according to any one of the preceding claims, CHARACTERIZED IN that means (w) for draining used liquid " reagent (R 1 ), is connected to a reagent container means (s..) via an elec¬ tronically controlled valve (M_), and channeling said used liquid reagent back to said reagent container means (S..) as long as the signal level from the photodetector means (D) is lower than a pre¬ determined value, and in other cases, channeling said used reagent to a means (s„) for waste reagent.

Inventors: MERENYI G, WLADIMIROFF W
Applicants: MERENYI G, WLADIMIROFF W
Application year: 1979
Main classification: G01N21
IPC codes: G01N21