Analysis of Powder Samples Using Fundamental Parameter Method

A new sequential benchtop wavelength-dispersive X-ray fluorescence spectrometer, the Supermini200, inherits all the features of the Supermini such as space saving and energy saving design, high-sensitivity because of a high-powered 200W tube, high spectral resolution using WDX optics and highly flexible and feature-rich operation software.

Enhancements to the spectrometer include:

• Oxygen analysis supported by SQX analysis
• Universal Power Supply for worldwide wall outlets
• Easier operation using an "EZ Analysis" window
• SQX Scatter FP method for powder samples (optional)

The latest WDX spectrometer from Rigaku is introduced in this article.

Features of Hardware and Software

The Supermini200 is a benchtop system developed for minimizing installation utilities, such as cooling water, power supply and installation space, etc. The spectrometer is compatible with worldwide wall outlets without any external electric transformer. The spectrometer is also equipped with an air-cooled 200W X-ray tube and up to three analyzing crystals, with which elements from oxygen to uranium can be analyzed. The helium gas is optionally available for chamber atmosphere, so that it is possible to perform liquid sample analysis. The hardware specifications of the Supermini200 are summarized in Table 1.

Figure 1. The Supermini200

The software offers users with convenient operation, the same as used the full-sized ZSX Primus series. As a new function, EZ Analysis window is added to the main menu, the intuitive user interface contains all operations used in a routine daily analysis as shown in Figure 2.

Figure 2. EZ Analysis window of the Supermini200.The window is composed of 3 panes, sample position (left), sample ID (upper right) and measurement information (lower right).

Table 1. Specifications of the Supermini200

The Supermini200 is the first benchtop spectrometer covering oxygen in semi-quantitative analysis, performed by SQX (Scan Quant X). By combining the analysis results of oxygen, the results of unknown polymer sample screening can be improved.

Newly Integrated SQX Scatter FP Method

SQX Scatter FP method is a function that is newly available on the Supermini200. This function is optimized for powder sample analysis. Semi-quantitative analysis by the fundamental parameter (FP) method is a useful method for elemental screening of materials. However, the FP calculation principally requires the information of all elements in a sample. This requirement is inconvenient on completely unknown sample analysis since the elements from hydrogen to oxygen are difficult to determine accurately by the XRF.

RIGAKU developed a new method for estimating and average atomic number for non-measured light elements in a sample using the intensities of scattered X-rays and applies this to the estimation of a balance component on the SQX analysis. This new function, SQX Scatter FP method, has been available for only the ZSX Primus series but now we can use this advanced method on the benchtop XRF spectrometer.

Two powder samples that cannot be precisely studied by traditional SQX method due to an increased amount of unmeasurable elements contained in the samples, are studied.

One sample is dehydrated cake (sludge residue), which is a residue that remains when sludge gets dehydrated. Another is sediment obtained from a deep sea floor. The Geological Survey of Japan (GSJ) supplied the JMS-2, which is a certified reference material. Both kinds of samples generally have complex matrices and contain moisture and certain organic matters with very wide variation. The well-dried samples were pressed into PVC rings and then analysis was done on the Supermini200.

The results of the SQX Scatter FP method are in line with the chemical and certified values as shown in tables 2 and 3. The successful results prove that this advanced method is available on the Supermini200 as well as on ZSX Primus series. This new function powered by RIGAKU's advanced FP technology expands the capabilities of the Supermini200 significantly.

Table 2. SQX results of dehydrated cake (sludge residue)

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unit: mass%

Table 3. SQX results of deep sea sediment (JMS-2)

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unit: mass%

This information has been sourced, reviewed and adapted from materials provided by Rigaku.

For more information on this source, please visit Rigaku.