JPS627973B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement of a liquid sample container for a fluorescence X-ray analyzer.

When all atoms are excited by X-rays of sufficient energy, a kind of photoelectric effect occurs, with K close to the inside of the electron shell, equivalent to when bombarded with accelerated electrons.
Electrons in orbits such as L are emitted to the outside of the atom, but the wavelength corresponding to the energy contributing to the emission becomes the absorption edge of the atom, and one kind of electron from the K orbit, L
Absorption corresponding to three types of energy levels occurs from the orbit, and electrons from the external L and M orbits fall into the orbits where these electrons have vacant levels, and the wavelength corresponding to the energy difference between the two levels is generated. X-rays are generated as fluorescence. This X-ray is called a secondary X-ray or fluorescence X-ray, and has a wavelength unique to each atom, and the wavelength becomes shorter for both the K series and the L series as the atomic number increases. In a fluorescence X-ray analyzer, a solid, powder, or liquid sample is excited with continuous wavelength X-rays to generate fluorescence X-rays, which are passed through a collimator and then a single crystal for spectroscopy is attached to a goniometer. , record the relationship of diffraction angle versus intensity by scanning with a suitable detector. According to the Bragg equation, nλ=2 d sinθ, so if we use a crystal whose crystal lattice spacing d is accurately known,
By measuring the diffraction angle θ, the wavelength λ is determined, and the analyte element is qualitatively determined based on this, and quantified based on the intensity.

By the way, in the case of a liquid sample, the primary X-rays from the X-ray tube pass through the liquid sample and are absorbed by the liquid and the bottom of the container, so the excitation efficiency of the fluorescent X-rays of the element to be analyzed is poor and One of the challenges was to further improve the sensitivity of liquid sample analysis.

This invention aims to enhance the analysis sensitivity by improving the liquid sample container, and the characteristic , which is attached to a liquid sample container of a fluorescence X-ray analyzer, which is equipped with a secondary X-ray excitation plate made of a material that is shorter than the absorption edge wavelength of the element to be analyzed and is composed of an element with a value as close as possible. be.

The fluorescence X-ray excitation efficiency from the test element can be improved by exciting it with a characteristic X-ray having a wavelength shorter than the absorption edge wavelength of the test element, and preferably the values of both wavelengths are as close as possible. It is a good idea to choose one that is available. A short characteristic X-ray wavelength means a high atomic number, so according to the periodic table of elements, elements that are higher than the element whose characteristic X-ray wavelength is the same as the absorption edge wavelength of the test element, Preferably, an element close to the top is selected and the test sample element is excited by the characteristic X-rays to improve efficiency. When the test elements are unknown or there are many different types, the one with the shortest predicted absorption edge wavelength is used for comparison.

Next, examples will be described.

The figure is a side sectional view of a liquid sample container of a fluorescence X-ray analyzer embodying the present invention. In the figure, 1 is the sample container body, which is made of a resin material that is inert to liquid samples and solvents, and has a liquid sample storage section 2 at the top and a bubble trapping section 3 at the bottom.
The middle part is connected by an inlet 4. 5 is the outer casing;
6 and 7 indicate the upper and lower bag nut lids, respectively, 8 is mylar film, 9 is the inner lid, 10, 1
1 indicates an O-ring.

To store the test liquid in this liquid sample container, first unscrew the lower bag nut lid 7, remove the inner lid 9, then turn the entire container upside down from the illustration and place the liquid sample in the container. Add a cup of. Then, when the inner lid 9 and bag nut lid 7 are fitted again and placed upside down, the air bubbles that got mixed in when storing the liquid will gather at the part 12, and the liquid sample containing part 2 will be filled with the untested liquid sample. is filled. When subjected to analysis using a fluorescence X-ray analyzer, the top surface of this container is placed in a vacuum chamber, and due to the resulting reduced pressure, the mylar film 8 is sucked slightly outward, but the inlet 4 Due to its downwardly protruding shape, no air bubbles are generated inside it.

Now, in the figure, reference numeral 13 denotes a secondary X-ray excitation plate, which is installed on the bottom surface of the liquid sample storage section 2.

This secondary X-ray excitation plate can be used when the liquid sample to be tested is heavy oil and the element to be analyzed is sulfur (S).
Rhodium (Rh) and the like are suitable. The absorption edge wavelength of sulfur is 5.018 Å, and the characteristic X-ray wavelength of rhodium is 4.597 Å for RLα ₁ and 4.374 Å for RLβ ₁ , which are short wavelengths, nearby, and easily available as a material, making it convenient to handle. It is from.

When the test element is titanium (Ti, absorption edge wavelength 2.49 Å), the excitation plate material is vanadium (V,
If the characteristic X-ray wavelength Kβ is 2.28 Å), but the test element is vanadium, the excitation plate material is chromium Kβ.
A 2.08 Å wavelength may be used.

The primary X-rays excites fluorescent X-rays from the element to be tested, and the portion that passes through the liquid without being absorbed irradiates the excitation plate 13 to excite secondary X-rays from the material element. These secondary X-rays further irradiate the element to be detected, which further excites fluorescent X-rays. These fluorescent X-rays and the fluorescent X-rays from the primary X-rays work together to excite the test element, so it is possible to obtain fluorescent X-rays with extremely high utilization efficiency of the excited X-rays. It is.

The thickness of the liquid layer in the liquid sample storage section 2 can be changed depending on the amount of sample, but the optimum conditions are experimentally selected by taking into consideration the absorption of secondary X-rays from the excitation plate 13 by the liquid layer. It will be.

Since the present invention is constructed as described above, it has the effect of improving the low fluorescence X-ray excitation efficiency of a liquid sample in fluorescence X-ray analysis and enabling highly sensitive analysis.

[Brief explanation of the drawing]

The figure is a side sectional view of a liquid sample container of a fluorescence X-ray analyzer according to an embodiment of the present invention. In the figure, each reference symbol below indicates a supplementary part.
0...liquid sample, 1...sample container, 2...liquid sample storage section, 3...bubble confinement section, 4...inlet, 5...outer casing, 6...bag nut lid, 7...bag Nut lid, 8... Mylar film, 9... Inner lid,
10...O-ring, 11...O-ring, 12...
Bubbles, 13... Secondary X-ray excitation plate.

Claims (1)

[Claims] 1. An element whose characteristic X-ray wavelength is shorter than the absorption edge wavelength of the element to be analyzed is formed on the inner surface of the liquid sample container in the direction opposite to the primary X-ray incident direction when viewed from the sample. A liquid sample container for a fluorescence X-ray analyzer in which a secondary X-ray excitation plate of a material to be used is arranged. 2. A liquid sample container for a fluorescence X-ray analyzer according to claim 1, wherein the thickness of the sample liquid layer can be changed by changing the position of the bottom body of the container provided with the secondary X-ray excitation plate. 3. A liquid sample container for a fluorescence X-ray analyzer according to claim 1, wherein the secondary X-ray excitation plate is replaceable.