LAB-X5000 Series User Guide
Appendix B: Sample Preparation
X-ray fluorescence spectrometry is a non-destructive method of analysis and it is possible to
measure a wide range of sample types using this technique. The nature of the sample is a very
important can adversely affect the accuracy of the analysis, however sample preparation is usually
very simple. Basic requirements are the sample should have a flat surface, be homogenous,
have an adequate thickness, and fit into the sample port of the instrument.
The LAB-X5000 will accept samples of diameter between 28 and 41 mm and height less than
39mm. Information in the preparation of several different sample types is given below. If
information of a more specific nature is required, contact your local Hitachi High-Tech Analytical
Science representative.
8.1.
Solids
Normal machine shop techniques such as lathe turning, milling, and surface grinding
8.1.1.
can all be used to obtain a suitable smooth and flat surface to give consistent
analytical results.
Lathe turning is the most widely applicable method (e.g. brasses, steels, nylons)
8.1.2.
although for materials with a tendency to smear, such as highly leaded brasses or
antimonial lead alloys, an end milled surface is preferred. Surface grinding is
generally highly reproducible.
Consistency of preparation is important and unknown samples should be prepared in
8.1.3.
the same way as the standards. Non-homogeneity should be eliminated or reduced
as well as is possible.
8.2.
Powders and Minerals
Most powders can be analyzed by simply pouring the powder into a sample cup.
8.2.1.
The sample cup should be lightly tapped on a clean bench to settle the contents after
8.2.2.
pouring.
Non-homogenous samples, low-density (‘fluffy’) samples or powders with larger
8.2.3.
particles must be ground and compacted into a pellet. Pellets provide a flat, smooth
sample of consistent density that is readily reproduced, minimizing error in analysis.
For information on pelletizing samples, contact your Hitachi High-Tech Analytical
8.2.4.
Science representative.
8.3.
Liquids
Liquids are poured directly into LAB-X sample cups.
8.3.1.
8.4.
Organic Solids
Food materials such as chelates, organo-metallic additives, catalysts, and trace
8.4.1.
catalysts are very soft and cannot be prepared in standard mills.
Powdered samples can be milled in a shaker/mixer mill to homogenize.
8.4.2.
Very soft materials, such as fats, can be homogenized in a food processor and then
8.4.3.
pressed into pellet form.
Calibration lines for elements in light organic matrices can be curved, leading to
8.4.4.
decrease in sensitivity at high levels. To dilute these samples to achieve linear
calibrations, use starch or sugar.
8.5.
Papers
A special device is available from Hitachi High-Tech Analytical Science for analyzing
8.5.1.
paper samples on the LAB-X5000. It was originally designed for the measurement of
silicone coating thickness but can be used for other thin samples.
The sample holder includes a special support that reduces unwanted background
8.5.2.
signals.
8.6.
Sample Cup Assembly
