Analysis of small samples in direct reading spectrometer analysis

The photoelectric direct reading spectrometer has basic requirements for the sample. The contact surface between the sample and the excitation table should be larger than the plane of the excitation hole (the excitation hole diameter is 10-15 mm). Therefore, many small size samples cannot be directly measured on a direct reading spectrometer. In order to solve the measurement of small samples, we have accumulated rich experience at home and abroad, and are widely used in practical analysis.

1. Boron nitride sheet method:

Boron nitride sheet method is a mature technology, has been applied for many years, the basic method is to use boron nitride as a ring, the general thickness is 1mm, the outer diameter is the same as the excitation hole of the photoelectric direct reading spectrometer, the inner diameter is 5mm or 8mm, Place the boron nitride sheet on the excitation hole and some small samples can be measured due to the reduced effective excitation aperture.

2. Fixture method:

Various fixtures have been developed at home and abroad to solve the analysis problems of wire and rod samples. The fixtures can be divided into two categories, one is a vertical clamp, which can analyze a bar with a diameter of more than 3 mm. The specific method is to clamp the sample with a clamp and place it in a position opposite to the electrode (position with a positioner) for excitation measurement. The other type is a horizontal clamp that can analyze 0.5~3mm wire. The specific method is to lay the wire on the excitation hole and perpendicular to the counter electrode, and use a special plastic cover to place the sample and the upper part of the clamp to prevent air from entering. People inspire the stage.

Different fixtures use different sample processing methods. The vertical fixture should be used to smooth the top of the bar. The flat clamp should be sanded with sandpaper. By using this method to control the sample with the same diameter, accurate results can be obtained.

3, mosaic method:

A small sample is inlaid with a mosaic material, and the mosaic surface is made into a plane for analysis.

4, sheet method:

For very thin sheets (<1 mm), the laser frequency can be reduced, the excitation time can be reduced, and the sheet metal sample can be pressed with a large piece of metal to increase the heat dissipation capability for measurement.

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