JPS6029893B2 - Atomic absorption spectrophotometer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an atomic absorption spectrophotometer, and particularly to the arrangement of a sample atomization section of an atomic absorption spectrophotometer.

There are several types of sample atomization devices used in atomic absorption spectrophotometers, depending on the type of element to be analyzed, the form of the sample, etc. As a typical sample atomization device, '1- Burner sample atomization device for samples in solution state.

■ For samples of 5 to 200 m9...Carbon cylinder furnace sample atomization device {3' For difficult-to-dissociate elements such as arsenic, selenium, antimony, etc....Reduction vaporization atomization device.

etc. are known.

A typical sample atomization device will be explained using diagrams.

FIG. 3 shows an embodiment of a burner sample atomization device used for solution samples. Aqueous solution sample 21
is housed in the sample container 22.

The sample is sucked up through the capillary tube 23. Air introduction pipe 25
Atomizer 24 (N
ebuljzer) sucks up the sample from the capillary tube 23. A Nebulizer 24 blows up the sample and at the same time turns the sample into a mist state.

The atomized sample is mixed with the fuel gas sent from the fuel gas introduction pipe 26. This mixture of air, sample mist, and fuel gas is sent to a burner 29 equipped with a long and narrow slit. By igniting this gas mixture injected from the slit of the burner 29, an elongated flame 27 is created. The sample solution, which has been made into a mist state beforehand, is dissolved into an atomic state in the flame 27. be separated. A light beam 28 from a hollow cathode lamp is transmitted through this elongated flame 27. The light rays are absorbed depending on the concentration of atoms contained in the flame 27. Figure 4 shows a carbon cylinder reactor atomization device (GraphiteAPmize) used for atomization of extremely small amounts of samples.
An example of r) is shown below. A section of the carbon cylinder is shown. The aqueous solution sample 32 is injected into the inside of the carbon tube 37 through the sample introduction hole 35 using a syringe.

The amount of sample 32 is usually 10 to 20 muku. A light beam 31 from a hollow cathode lamp is guided to the center of the inner diameter of a carbon tube 37 and a carbon tube 36 that is electrically in close contact with the carbon tube 37 . A current-carrying wire 38 is connected to the carbon tube 36 in an open manner. The other end of the energizing line 38 is connected to a power source 39. The carbon tube 36 and the carbon tube 37 are connected to the power source 39 as a resistive load.

By supplying current from the power source 39 to the carbon tubes 36 and 37, these resistive loads are heated to a high temperature. The aqueous solution sample 32 housed inside the carbon tube 37 evaporates, and the solute is dissociated into atomic states at high temperatures. This carbon tube 37
The atomic absorption phenomenon can be observed by guiding the light beam 31 of the hollow cathode lamp to the atomic vapor created inside the atomic vapor. FIG. 1 shows an example of a conventional atomic absorption spectrophotometer.

A resonance line of the same atom as the analysis target atom (Reso
The rays of the cape are emitted. The light rays are focused by the first lens 2 onto the central part of the frame 3. Sample 1
2 is introduced into the frame 3 in a mist state mixed with the aforementioned air 13 and fuel gas 14. The light beam transmitted through the frame 3 is converged again by the second lens 4 and guided to the entrance slit of the spectrometer. Diffraction grating 8
The resonance absorption line of the same atom as the analysis target atom dispersed by the cation grating is guided to the phototube 9.

After the signal is processed by amplifier 1, it is sent to display 1.
1 is displayed. In FIG. 1, the sample atomization device is the burner sample atomization device explained in FIG.
It is attached between the lens 2 and the second lens 4. In the conventional apparatuses, only one of them is a burner sample atomization apparatus shown in Fig. 3, a carbon tube furnace sample atomization apparatus shown in Fig. 4, a reduction vaporization sample atomization apparatus, etc. It is installed in a photometer.

These sample atomization devices were installed and replaced depending on the form and type of sample to be analyzed.

In the conventional atomic absorption spectrophotometer shown as an example in FIG. 1, the work of replacing the sample atomization device is complicated as follows. '11 Accurate positioning and layer alignment is required so that the light beam of the hollow cathode lamp passes through the center of the flame of the burner atomizer.

In a carbon cylinder reactor atomization device, a minute distance adjustment is required so that the light beam of the hollow cathode lamp passes through the center of the carbon cylinder. {21 For samples with the same concentration of specific elements, the relative position of these sample atomization devices to the light beam of the hollow cathode lamp is slightly (0.2 to 0.
5) If different, the signal obtained from the atomic absorption spectrophotometer will change.

That is, the sensitivity of the atomic absorption spectrophotometer to the sample element changes. Therefore, in actual analysis, it is known from experience that even if the same sample atomization device is installed again after replacing the sample atomization device, the same sensitivity cannot be obtained. Of course, the degree of change in sensitivity is not necessarily constant depending on the actual device. '3} The sample atomization apparatus shown in Figures 3 and 4 requires connection to air, fuel gas, or cables that carry several hundred amperes of electricity, so the operation itself is difficult. be. The present invention provides a new atomic absorption spectrophotometer that eliminates the drawbacks of such conventional devices.

For this reason, the present invention is configured to arrange two or more types of sample atomization devices in series on the optical path from the light source to the photodetector, and to selectively use these two or more types of sample atomization devices. This is what I did. The content of the present invention will be explained using figures.

FIG. 2 shows an embodiment of an atomic absorption spectrophotometer according to the present invention. Compared to the conventional example shown in FIG. 1, the atomic absorption spectrophotometer shown in FIG. The feature is that it is arranged so that it can be The light rays emitted from the hollow cathode lamp 1 are focused on the center part of the frame 3 by the first lens 2, and are focused on the center part of the carbon tube furnace 5 by the second lens 4. Thereafter, it is focused by the third lens 6 and imaged at the entrance slit position of the spectroscope. When using the frame sample atomization device 3, the carbon pipe line 5 is not used.

Further, when using the carbon tube 5, the frame sample atomization device 3 is not used. It is clear that the two sample atomization devices can be used selectively depending on the purpose of analysis without having to be moved.

In order to simplify the explanation, FIG. 2 shows a case where two sample atomization devices are installed, but after the third lens 6, for example, a reduction vaporization sample atomization device is placed, and a fourth lens is installed. to focus the light beam onto the input slit of the spectrometer.

In FIG. 2, the one closest to the hollow cathode lamp 1,
The reason for arranging the frame sample atomization device 3 is that another effect as described below can be obtained.

In the flame sample atomization device, when, for example, 100 melons of elements such as sodium and potassium are dissolved and inhaled as the aqueous solution sample 12, the light beams of sodium and potassium emitted from the frame 3 are transferred to the hollow cathode lamp. Can be used in place of 1.

In this case, elemental analysis can be performed without using the hollow cathode lamp 1. In the atomic absorption spectrophotometer which is an embodiment of the present invention shown in FIG. 2, two sample atomization devices are arranged simultaneously, the samples are introduced alternately, and the two samples are separated by a time division method. The effect of using the atomization devices alternately can also be expected. As mentioned above, the present invention eliminates many of the drawbacks caused by the fact that only one or only one sample atomization device can be arranged in conventional atomic absorption spectrophotometers by using an extremely simple and easy method. It is characterized by the ability to

In addition, by alternating and slightly shifting sample introduction and measurement times, it is possible to use two or more sample atomization devices simultaneously, increasing the analytical work efficiency of a single atomic absorption spectrophotometer. is also a feature.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the configuration of a conventional atomic absorption spectrophotometer, FIG. 2 is a diagram showing the configuration of an atomic absorption spectrophotometer according to an embodiment of the present invention, and FIGS. FIG. 4 is a schematic diagram of the sample atomization device. DESCRIPTION OF SYMBOLS 1... Hollow cathode lamp, 3... Frame, 5... Carbon tube furnace, 9... Phototube. Younger brother/Fig. 3 Fig. 2 Fig. 4

Claims (1)

[Claims] 1. Two or more types of sample atomization devices are arranged in series on the optical path from the light source to the photodetector, and the two or more types of sample atomization devices are configured to be used selectively. Atomic absorption spectrophotometer.