RU2308708C2 - Fluorometer - Google Patents

Abstract

FIELD: spectrophotometry.

SUBSTANCE: fluorometer contains first and second light sources with different wave lengths, first and second photo-detectors with outputs for connection to a system for transmission and recording of measurement results, where external surface of fluorometer body on the side of incoming flow has streamline cylinder shape, light-sensitive zones of first and second photo-detectors face the incoming flow, and directions of emission of light beams by first and second light sources form sharp angles with axes of aforementioned light-sensitive zones. Transmission and registration system contains first and second amplifiers, outputs of which are connected to inputs of analog-digital converter, to output of which preliminary processing device is connected, which by means of first and second adapters of data transmission channel and data transmission channel itself is connected to electronic computing machine, to which a memorizing device and a displaying device are connected.

EFFECT: increased precision of measurement in a flow of liquid.

2 cl, 5 dwg

Description

The invention relates to spectrofluorometry and can be used to measure the concentration of various substances in specialized complexes or systems installed on mobile carriers.

The practice of modern oceanographic research shows that in solving a number of problems, precision measurements and operational processing of various hydrophysical information in real time on board the equipment carrier during long-term operation are necessary. The main goal of such studies is the construction of information maps, the study of their temporal and spatial variability, fine structure, identification of abnormal hydrophysical zones, etc.

A known method for the determination of chlorophyll in an aqueous medium [1], which consists in carrying out the excitation of fluorescence of an aqueous medium and measuring the signal of fluorescence intensity, which is determined. The method does not allow for the contamination of the walls of the fluorimeter cell.

There is also a method of determining the chlorophyll of phytoplankton in an aqueous medium [2], which takes into account the pollution of the walls of the cell. In the course of work to determine the chlorophyll content of phytoplankton in an aqueous medium, it was shown that the walls of the flow cell of the fluorimeter were coated with plaque, which continuously impaired its optical properties.

This method has the following disadvantages: the long duration and complexity of the process of obtaining an estimate of the influence of plaque on the measurement results, since it takes considerable time to perform the necessary measurements of fluorescence intensity; low accuracy of accounting for the effect of pollution on the final result.

A known method is based on measuring the light signal of the fluorescence intensity from the contents of the cuvette, followed by the introduction of a correction coefficient on the result of measuring the fluorescence intensity of the test medium, according to the invention, a standard is placed in a clean and contaminated cuvette, both times determine the intensity of the light signal from it for the same irradiation conditions and registration, as for the studied medium, and the correction factor is determined based on the data obtained [3]. As a reference, either a substance similar in spectral properties to the medium under study is used, or distilled water with the same temperature for both measurements, or a mirror with the ability to reflect light in the direction of measuring the fluorescence intensity of the medium under study. In this case, if the last two standards are used, then the cuvette is irradiated for the first time in the spectral band, which is the excitation band for the medium under study, and light is recorded in this band, the second time is irradiated in the spectral band, which is the registration band for the studied medium, and light is recorded in the same strip.

Known fluorimetric detector [4], containing a light source, focusing optics, a capillary with a sample, a parabolic mirror, a light filter, a photodetector, while the detected volume of the sample is located in the focus of the mirror so that the fluorescence radiation collected by the mirror forms a quasi-parallel beam, characterized in that it is equipped with a spherical mirror, the focus of which is conjugated with the focus of the parabolic mirror, the mirrors being located on one axis perpendicular to the plane in which the axis of the exciting radiation and the capillary are extended, and it contains a CCD matrix of an additional photodetector installed in the direction specularly reflected from the capillary with a beam breakdown, while the radiation source and / or capillary are movable with the possibility of movement in a direction perpendicular to their axes.

All the above methods and devices for measuring are unsuitable for measurements in dynamic mode.

The fluorimeter [5] is also known, which, by its technical nature, is closest to the proposed one. The prototype fluorimeter contains a light source connected to a source of exciting voltage, and a photodetector with an output for connecting to a transmission system and recording measurement results. In this case, the light source and the photodetector are located in two separate buildings, and the axis of the light source and the axis of the photodetector are perpendicular to one another.

The disadvantage of the fluorimeter prototype is the low accuracy of measurements in fluid flows.

The problem solved by the invention is the creation of a fluorimeter that provides a quantitative assessment of the measured parameters in the fluid flows.

The essence of the invention lies in the fact that the fluorimeter contains the first and second light sources with different wavelengths of the emitted light, respectively connected to the first and second sources of exciting voltage, the first and second photodetectors with outputs for connecting to the transmission system and recording the measurement results, while the outside the surface of the fluorimeter body on the side of the incoming flow has the shape of a streamlined cylinder, optical communication with the test medium of the first and second light sources, as well as the first and second photodetectors equipped with light filters is carried out using quartz glass lenses having a cylindrical surface mating with the outer surface of the housing, and the back surface of the lenses is flat, the photosensitive zones of the first and second photodetectors are directed towards the incident flux, and the light beam emission directions are first and the second light sources form sharp angles with the axes of the photosensitive zones of the first and second photodetectors, respectively, while transmitting and recording the measurement results contains the first and second amplifiers, the outputs of which are connected to the inputs of the analog-to-digital converter, the output of which is connected to a preliminary processing device, which is connected to the electronic computer by means of the first and second adapters of the data channel and data channel which connected the storage device and the display device.

In the proposed fluorimeter, the first light source has, in particular, the wavelength of the emitted light 520-540 nm, and the second 360-380 nm.

In the proposed fluorimeter, the electronic computer has a set of external interfaces.

The invention is illustrated by drawings, which depict:

figure 1 - the design of the fluorimeter, a side view in longitudinal section;

figure 2 - design of the fluorimeter, front view;

figure 3 - design of the fluorimeter, top view;

figure 4 is a functional diagram of a fluorimeter;

figure 5 is a structural diagram of a system for transmitting and recording measurement results.

Figure 1-5 marked:

1 - the first light source;

2 - the second light source;

3 - the first photodetector;

4 - the second photodetector;

5 - output of the first photodetector 3;

6 - output of the second photodetector 4;

7 - a system for transmitting and recording measurement results;

8 - case;

9, 10 - light filters;

11-14 - lenses;

15 - a cylindrical surface of the lenses;

16 - the outer surface of the housing 8;

17 - the direction of radiation of the light beam by the first light source 1;

18 - the direction of radiation of the light beam by the second light source 2;

19 - axis of the photosensitive zone of the first photodetector 3;

20 - axis of the photosensitive zone of the second photodetector 4;

21 - the first source of exciting voltage;

22 - a second source of exciting voltage;

23 - the first amplifier;

24 - the second amplifier;

25 - analog-to-digital Converter;

26 - pre-processing device;

27 - the first adapter of the data channel;

28 - second adapter data channel;

29 - electronic computer;

30 - storage device;

31 - display device;

32 - external interfaces;

33 - data transmission channel.

The proposed fluorimeter contains the first and second light sources 1 and 2, made in the form of LEDs with different wavelengths of the emitted light. In particular, source 1 has a wavelength of emitted light λ ₁ = (520-540) nm, and source 2 has λ ₂ = (360-380) nm (see FIG. 1). The use of two light sources makes it possible to simultaneously record the fluorescence of chlorophyll [recorded wavelength λ _1p = (650-700) nm] and soluble organic matter (DOM), which is mainly due to dead biogenic lime [recorded wavelength λ _2p = (460-480) nm].

The fluorimeter also contains the first and second photodetectors 3 and 4 with outputs 5 and 6 for connecting to the transmission system 7 and recording the measurement results (see figure 4.)

Light sources 1 and 2, photodetectors 3 and 4, as well as a system 7 for transmitting and recording measurement results are made according to the usual schemes used in the construction of fluorimeters, and do not have any features.

The system 7 for transmitting and recording the measurement results contains the first and second amplifiers 23 and 24, the outputs of which are connected to the inputs of the analog-to-digital converter 25, to the output of which the preliminary processing device 26 is connected, which through the first and second adapters 27 and 28 of the data channel and channel 33 data transmission is connected to an electronic computer 29, to which a storage device 30 and a display device 31 are connected.

The A / D converter 25 has at least two inputs. As the device 26 pre-processing can be used a microprocessor device, for example a single-chip electronic computer based on a digital signal processor. The pre-processing device 26 averages the data received from the analog-to-digital converter 25, digitally filters them and converts them to a form convenient for transmission via data transfer channel 33 (for example, generating data packets).

Various known interfaces, such as RS-232, RS-485, as well as multiplexed data channels, such as MIL-STD-1553 or various modifications of the Ethernet network, can be used as the data transfer channel 33. In the case of using multiplexed data channels as a data channel 33, a channel can also be used, which is also used to transmit data from other sensors and measuring devices in close proximity to light sources 1 and 2 and the first and second photodetectors 3 and 4 (i.e. with the optical part of the fluorimeter).

As an electronic computing machine 29, a personal or industrial computer may be used. A display device 31 is connected to the electronic computing machine 29, which can be used, for example, as a monitor, recorder, printer, alphanumeric indicator, etc. A storage device 30 is also connected to the electronic computing machine 29, which can be used as a hard disk drive, a magnetic tape drive, a device based on electro-reprogrammable read-only memory devices (Flash-memory), as well as any known storage devices, including including removable storage media.

The electronic computer 29 has external interfaces 32, which can be used such interfaces as serial interface RS-232, USB, Ethernet network interface, multiplexed communication channels MIL-STD-1553, etc. External interfaces 32 are used to provide the ability to connect to the electronic computing machine 29 additional display and documentation devices, as well as data receiving and transmitting devices for communicating the electronic computing machine 29 with other computing devices and systems, which allows the operation of the fluorimeter as part of complex systems analysis, for example, as part of integrated environmental monitoring systems.

A design feature of the proposed fluorimeter is that the outer surface of the housing 8 from the side of the incoming flow has the shape of a streamlined cylinder (in FIG. 3, the direction of the incoming flow is conventionally shown by arrows).

Optical communication with the test medium of the first and second light sources 1 and 2, as well as the first and second photodetectors 3 and 4, equipped with filters 9 and 10, is carried out using lenses 11-14 of quartz glass having a cylindrical surface 15, conjugated with the outer surface 16 buildings 8.

The photosensitive zones of the first and second photodetectors 3 and 4 are directed towards the incident flow, and the directions of light emission from the first and second light sources 1 and 2 form sharp angles α with the axes 19 and 20 of the photosensitive zones 3 and 4 of the first photodetectors ( see figure 2) Typically, the angles α are from 10 ° to 45 °.

The proposed fluorimeter works as follows.

To measure the concentration of various substances in the liquid stream, the fluorimeter is installed in the liquid stream so that the generatrix of the outer cylindrical surface 16 of the housing 8 is perpendicular to the direction of the incoming liquid flow, and the photosensitive zones of the first and second photodetectors 3 and 4 are directed towards the incident stream.

In this case, the first and second light sources 1 and 2 are connected respectively to the first and second sources of exciting voltage 21 and 22, and the outputs 5 and 6 of the first and second photodetectors 3 and 4 are connected to the inputs of the system 7 for transmitting and recording measurement results. The emission of light flux by sources 1 and 2, the reception of signals by photodetectors 3 and 4, their processing are carried out by conventional known methods.

Due to the proposed design of the fluorimeter, a smooth flow of fluid around the body is achieved, while the concentration of the test substances is measured in a slightly disturbed flow region, which eliminates the errors associated with the violation of the structure of the studied flow.

The technical result consists in increasing the accuracy of the measurement in the fluid flow.

At the applicant plant, a prototype of the proposed fluorimeter was manufactured and tested. Tests of the prototype confirmed the possibility of obtaining the specified technical result.

Thus, the presented drawings and description make it possible, using the existing elemental base and technologies, to manufacture the proposed fluorimeter in an industrial way and use its concentration measurements of various substances in specialized complexes or systems mounted on mobile carriers, which characterizes the invention as industrially applicable.

Information sources

1. USSR copyright certificate No. 1473518, IPC G01N 21/64, 1987.

2. T. Platt. The feasibility of mapping the chlorophyll distribution in the gulf of St. Lawrenge. Fisheries research board of Canada. Technical report. N 332. August, 1972, p. 1-3.

3. RF patent No. 2031399, IPC G01N 21/64, 1995.

4. RF patent No. 2182329, IPC G01N 21/64, 2002.

5. US patent No. 4293225, IPC G01N 21/64, 1981 (prototype).

Claims (2)

1. A fluorimeter containing the first and second light sources with different wavelengths of the emitted light, the first and second photodetectors with outputs for connecting to a transmission and recording system of measurement results, while the outer surface of the fluorimeter body on the incoming flow side has the shape of a streamlined cylinder, optical communication with the test medium of the first and second light sources, as well as the first and second photodetectors equipped with light filters, is carried out using quartz glass lenses having a the cylindrical surface conjugated with the outer surface of the casing, the photosensitive zones of the first and second photodetectors are directed towards the incident stream, and the direction of radiation of the light beams by the first and second light sources form sharp angles with the axes of the photosensitive zones of the first and second photodetectors respectively, while the system of transmission and recording of results measurements contains the first and second amplifiers, the outputs of which are connected to the inputs of the analog-to-digital Converter, to the output of which Keys pretreatment device which by means of first and second adapters data channel and the data channel associated with the computing machine which is connected to the storage device and a display device. 2. The fluorometer according to claim 1, characterized in that the first light source has a wavelength of emitted light 520-540 nm, and the second 360-3-380 nm.

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