SU730066A1 - Atomic flu orescent analyzer - Google Patents

Description

(54) ATOMIC-FLUORESCENT ANALYZER

one

The invention relates to the creation of atomic fluorescence analyzers with automatic adjustment of the scattered radiation.

Atomioabsorption analyzers are known, which provide for the correction of interfering scattered results of text 1,

The closest technical solution to the invention is an atomic absorption analyzer, which contains a source of a line spectrum, a source of a continuous spectrum, working in a stationary mode, lighting systems of light sources separated relative to each other, equalizing, its structure, obturator, atomizer, a monochromator, a photodetector and an electronic recording device 2.

The disadvantages include the low accuracy of measurements, the complexity of the design of the obturator and the low reliability of the analyzer.

The aim of the invention is to improve measurement accuracy, simplify the construction of the obturator and increase the reliability of the analyzer.

This goal is achieved because the obturator, located in front of the continuous spectrum source, is designed as

a disk chopper, the line source of light being connected to a source of pulsed power synchronized with the obturator with the help of an electronic device that adjusts its alternate cooling of the light fluxes from both sources through the atomizer.

FIG. Figure 1 shows the optical scheme of an atomic fluorescence analyzer; on

10 of FIG. 2 is a diagram of the arrangement of disks and sensors of the obturator; in fig. 3 - time schedules of light and electrical signals arising from the operation of the analyzer. In the atomizer 1 enter the analyzed

15, under the action of heating, free atoms of the element being detected are formed. Light from a continuous spectrum source 2 with its own optical system consisting of lenses 3 and 4 and mirrors 5 and 6 is directed

20 through the atomizer 1. The shutter disk 7 periodically blocks the radiation from source 2, with the result that the time dependence of the radiation flux falling on the atomizer from source 2 is determined

25 by schedule 1 shown in FIG. 3. On the same axis with the disk 7 of the obturator is the usan-sen disk 8, switching contactless sensors 9 and 10, from which signals are sent to the registering device 11, depending on which time is shown respectively in graphs 2 and 3 (Fig. 3). The disks 7 and 8 of the obturator are driven in rotation by the engine 12 through the actuator 13. The ruled light source 14 operates in a pulsed mode and is powered by a pulsed power source 15, and the current pulses transmitted by the power source 15 through the light source 14 are synchronized with the pulses from the sensor 10 Thus, the radiation pulses of the light source And are also synchronized with the pulses from the sensor 10 and are shown in graph 4 (Fig. 3). Luminous flux from source 14 using an optical system consisting of lenses 16 and 17 and mirrors 18 and 19, directed through the atomizer 1, excites the fluorescent radiation, which through lens 20 enters the input of the monochromator 21; A photomultiplier 22 is installed at the output of the monochromator. The dependence of the magnitude of the signal at the output of the photomultiplier on time is shown in graph 5 (Fig. 3).

Provided that the spectral slit width of the monochromator is much larger than the width of the absorption line, approximately equal to the width of the line emitted by the line source of light, the fluorescent radiation excited by the continuous spectrum source can be neglected compared to the fluorescent radiation emitted by the line light source.

To perform the operation of adjusting the scattered radiation, a substance that scatters radiation but does not contain the atoms of the element being determined is introduced into the atomizer 1; Equalizing the amplitude of the sigals excited by the light sources 2 and 14 using an equalizing device 23, such as an iris diaphragm, provides measurement conditions at which the mixed diffuse radiation is automatically subtracted. The recording device AND provides for recording and integrating the signal from the photomultiplier output for a time t when emitting a radiation pulse by a linear light source and recording and integrating the signal from the photomultiplier output for a period of time t when passing radiation from a continuous source

spectrum through an atomizer; then the second signal is subtracted from the first. The resulting signal difference is proportional to the magnitude of the fluorescent signal and, therefore, to the concentration of the atoms to be detected. Graph 5 (Fig. 3) is plotted for the magnitudes of the signals obtained after performing the equalization operation. An output signal proportional to the detected concentration is measured over instrument 24.

The magnitude of the scattered radiation depends on the angle at which the scattered radiation is observed and recorded, therefore the angles of the analyzer are

5 AOOi and BOO are equal.

FIG. 3, in addition to the foregoing, the following notation is introduced: F2 is the radiation flux from the light source 2 passing through the atomizer; UQ - signal from the sensor

0 9; f / io - signal from sensor 10; Fc is the radiation flux from the light source 14; Gfeu - a signal from the output of the photolumn ITEL; / f., - fluorescent signal; / ras - scattered signal; / pl - nlameni radiation; t - time 5 m.

Claims (2)

1.T. C. Rains at al. Analytical chemistry. V. 46, LI 2, p. 207, 1974. 2. The UK patent number 1455327, cl. G 01 J 3/42, published. 1976. Z FIG ..