Most often in analytical practice of laboratories fluorimetrichesky detectors are used for quantitative definition of the following substances:
- polyaromatic hydrocarbons (PAU) in food products, drinks and drinking water;
- aflatoxins of B1, B2, G1i G2 in foodstuff;
- M1 aflatoxin in milk, and dairy products;
- ochratoxin A in wine, juice and soft drinks;
- OPA-and other fluorestsiiruyushchy derivative amino acids in different samples;
- a large amount of other fluorescent materials in chemical and pharmaceutical laboratories and productions.
The fluorimetrichesky detectors existing in the market of the chromotographic equipment, as a rule, use as a light source or a combination from deyteriyevy and halogen lamps, or the xenon lamp of a high pressure. Apply to selection of the necessary wavelength or the monochromator with electronic and mechanical fine tuning of diffraction grating or a set of interferential light filters. The interservice interval of operation of such devices depends on a resource of stable work of radiation sources which for modern deyteriyevy and xenon lamps makes from 1000 to 2000 hours. Besides, they need intensive forced cooling and application of complex electron-optical systems for stabilization of work of a light source that in turn negatively influences stability of operation of the device in general. Use of the monochromator or light filters as the selector of wavelength leads to considerable deceleration of power of radiation in analytical a ditch. Often used monofiber lightguides also reduce an amount of light moving on a cell.
During creation of the fluorometric detector for the range "Stayer-M" other approach was selected. In the detector DFL-203 as a light source LED UV sources thanks to which it was succeeded to raise sharply indicators of reliability, simplicity of service and maintainability when saving the main technical and analytical characteristics are applied. Special construction ditches allows work with a pressure up to 30 bars. The low-noise photo multiplier provides increase of sensitivity and improvement of a signal-to-noise ratio. As a result the compact and reliable detector with LED initiation of fluorescence turned out. In construction of the detector there is no moving part, except the switching gear of the cutting light filters. The device is issued with the preset LEDs on 280/365 nanometers or 255/365 nanometers that allows to solve practically any analytical problems. By the special order delivery of the device with other couples of exciting LEDs is possible. Construction of the detector is protected by the Russian and international patents.
Some features of the detector
- The minimum quantity of optical and mechanical elements leads to the raised indicators of reliability and stability of the device.
- Materials optical ditches allow to use solvents with pH from 0 to 14.
- Application of highly stable semiconductor light sources provides low noise and long service life of the device with invariable characteristics.
- Fast output on an operating mode, in most cases till 5 min.
- Possibility of manual and program control.
- Possibility of work with the third-party software through RS-232 port.
- Possibility of connection of external ATsP through an analog output.
- Unique parameters of maximum working pressure in a cell (30 bars) give the chance of work with external hydroresistance (suppression of formation of large air bubbles in a liquid path at not decontaminated or insufficiently decontaminated eluent).
- Lengths of waves of initiation of fluorescence of-280 and 365 nanometers or 255 and 365 nanometers. By the special order installation of LEDs with other wavelength is possible.
- Maximum speed of a flow through a ditch - 10 ml/min.
- The detected volume - ~ 10 mkl.
- Possibility of work from networks of power supply of different tension (100-240 V).
- Minimum energy consumption (~ 20 W).
Main technical characteristics
|Detecting limit on anthracene,||1·10-14|
|Lengths of waves of light sources (two monochromatic LEDs), nanometer||280 and 365; 255 and 365 *|
|The detected volume, mkl||10|
|Maximum speed of a flow through a ditch, ml/min.||10|
|Maximum pressure in an optical cell, bar||10|
|Output time for an operating mode, min., no more||10|
|Spectral range of measurement: switched
(discrete, selected), nanometer
|Time of averaging of a signal, with||0,5/1,0/2,0|
|Output time for an operating mode||10 min.|
|Range rn eluent, unit rn||0 - 14|
|Power supply, tension/frequency||110-220B/50gts|
|Power consumption, no more||20 WA|
|Remote software updating of the processor||yes|
|Interfaces||Akvilon BUS; RS-232; USB;
The most priority substance for monitoring from class PAU from the point of view of analytical control certainly is benz (and) pyrene - one of the most terrible carcinogens, requirements to which content (maximum concentration limit) extremely rigid and in Russia, and around the world.
For drinking water of the centralized systems of drinking water supply the maximum permissible concentration (MPC) benz (and) pyrene makes 0,000005 mg/l = 5·10-6 mg/l = 5·10-9 g/l (item 220.127.116.11. SanPiN 18.104.22.1684-01).
For water of water objects of economic and drinking and cultural and community water use maximum permissible concentration (MPC) benz (and) pyrene of 0,000001 mg/l = 1·10-6 mg/l = 1·10-9 g/l (item 2. GN 2.1.5. 1315-03).
Benz (a) pyrene is carried to the first class of danger (extremely dangerous). For this reason benz (and) pyrene we paid to metrological characteristics of the detector at determination of mass concentration special attention and considered this substance as the indicator.