Volume 37(1) - Winter 2021

X-ray fluorescence (XRF) spectrometry allows both simple sample preparation and high precision analysis.  The method is highly popular among various fields, including quality control and research & development.  Recent advanced data processing techniques and higher instrument sensitivities have improved analytical accuracies in “standardless FP analysis” using Fundamental Parameter (FP) method which does not require standard samples. However, standard samples which are similar sample type to analysis samples are still required to create calibration curves in order to obtain high accuracy analysis results.

There are wide variety of analyzing elements and concentration ranges to analyze common oil types such as fuel oils of gasoline and heavy oil, lubricating oil, and waste oil. It requires high level knowledge of X-ray fluorescence analysis in order to purchase suitable commercial reference materials and create all calibration curves after setting proper measuring parameters.  Furthermore, it requires high cost and time. Therefore, there has been high demands of simple analysis startup method for accurate analysis of various types of oils.

The new analysis package for oil analysis is designed for beginners of X-ray analysis to setup quantitative analysis of oils easily and quickly by supplying a package of data media consisting of intensities of standard samples, analytical parameters and drift correction samples.

Oil analysis is carried out by measuring oil sample using liquid cell directly filled with oil sample, which is covered by sample film. However, since the sample film mainly consists of light elements such as carbon and hydrogen, the film causes negative impacts to the sample analysis as follows:

• Since main components of oils are hydrocarbons added with oxygen, it is required to correct for the influence of composition variation of carbon, hydrogen, and oxygen.
• For analysis of heavy elements in light matrix samples, incident X-rays penetrates into sample deeply and fluorescent X-rays generated in deep area can transmit sample area and detected. However, there are areas where generated fluorescence are not detected in deep area inside sample and the undetected area depends on X-ray optics of the spectrometer. This phenomenon is called geometry effect.

Moreover, there is a wide variety of sample films and selection depends on analysis type and purpose such as sensitivities, impurities, and durability against chemical characteristics of liquid and X-ray damage.

OIL-MULTI-PAK, application package for multielement analysis in oils provides solutions to solve the problems above allowing accurate analysis for wider range of oils, including used lubricating oil, lubricating oils with various types of base oils, and fuel oils such as heavy oil, diesel oil, and gasoline.

XY mapping measurements to obtain physical values for your analysis purpose is one of the best ways to analyze the state distribution of a substance, the strength distribution of a material or a device, etc. The significant progress in X-ray sources, optical devices and detectors has enabled the irradiated area to be narrowed and low X-ray intensities to be detected. It is becoming possible to evaluate smaller (or smaller areas of) materials without high-cost optical devices or attachments. This article describes the following experiments and analysis:

• The sample was moved in the X and Y directions step by step using an XY attachment;
• The X-ray beam was conditioned by an optical device called CBO-μ and irradiated onto a small area;
• The X-rays diffracted from the sample were collected using the HyPix-3000 2D hybrid pixel array detector;
• The collected data sets were analyzed using the Data Visualization plugin of the integrated X-ray analysis software SmartLab Studio II.

Diffraction-based characterization of epitaxial thin films, such as the measurement of the composition, strain, and lattice constants, requires complicated alignment processes of the X-ray optics. Rigaku’s multipurpose X-ray diffractometer, “SmartLab,” features an automatic alignment function, which greatly simplifies the process. However, it still requires a timeconsuming re-alignment process when, for example, switching the optics between the standard and the highresolution optical systems, which use the slits and an analyzer crystal, respectively.

Generally, before the measurement of a sample with high crystallinity, such as a single crystal substrate or an epitaxial film, it is necessary to adjust the crystal orientation of the sample so that the measurement direction with a goniometer matches the crystal orientation. This procedure, called “axial adjustment,” sometimes requires a modest resolution optics because the reflections can be difficult to find when the crystal orientation is tilted or the lattice constants are different from the literature values. There are also some types of measurements that do not require the high-resolution optics. Therefore, the ability to switch between the slit optical system, which has a relatively low resolution, for the axial adjustment and the high-resolution analyzer-crystal optical system for actual data collection will enhance the efficiency of the whole process.

The HyRES has been designed to simplify this switching process. This is a receiving optical device that has two optical paths: a slit optical system and a high-resolution optical system with an analyzer crystal.  When combined with the HyPix series multidimensional pixel detector, the HyRES unit allows the user to seamlessly switch between the two optical systems through software control without a need of switching the optics hardware.

In this article, the principle and the features of the HyRES unit will be introduced with some analysis examples.
 

Halogen elements correspond to Group 17 in the periodic table and include fluorine (F), chlorine (Cl), bromine (Br) and iodine (I). Materials and products containing halogens are widely used in our daily life. For example, fluorine is contained in Teflon® resin and toothpaste, chlorine is contained in salt and vinyl chloride resin, and bromine is contained in flame retardants in plastics and photosensitizers.  While these halogen elements provide useful features to various products, they can also have adverse effects on industries and the environment.

• Corrosion in production equipment
• Environmental regulations
• Countermeasures against defects in semiconductors, electrical devices

For these reasons, halogen elements are analyzed in various industries for acceptance inspection and quality control during manufacturing. Especially in fields where the number of samples to be measured is large, a method capable of quick and easy analysis is required.

Combustion-ion chromatography and inductively coupled plasma optical emission spectrometry (ICP-OES) are widely used as methods for analyzing halogen elements. However, these methods require complicated sample preparation techniques and equipment maintenance. On the other hand, it is possible to obtain analysis results quickly by using X-ray fluorescence (XRF) spectrometry because sample preparation and instrument maintenance are easy and analyzing time is short. Because of these advantages, XRF is widely used in industries. Examples of the analysis of halogen elements in various samples using XRF are described in this article.
 

It is necessary to obtain high-quality data for highly accurate analysis. The characteristics of high-quality data may be high intensity, high resolution, high P/B (peak-to-background ratio), and high S/N (signal-to-noise ratio). Deciding which features are important depends on the purpose of analysis. Therefore, we need to consider measurement conditions after determining the purpose of analysis. Some combinations of sample types and optical systems prevent the desired results from being obtained. Therefore, it is necessary to select the optical systems according to the kinds of samples.

The equipment configurations required to obtain high-quality data will be explained here and in the following articles in this powder X-ray diffraction basic course.  The measurement conditions we will be discussing include selection of the equipment, sample preparation, and scan conditions. Selection of the equipment will be covered in this article, and sample preparation and scan conditions will be discussed in the third article.

The following sections in this article explore the factors involved in selecting the proper equipment configurations to obtain high-quality data: 2. Selection of X-ray source, 3. Selection of optical systems, 4. & 5. Setting incident and receiving optical systems, and 6. Detector configuration. These sections are arranged in order from the X-ray source to the receiving optical system.
 

Molecular structure determination is very useful for the development of medicines, aroma chemicals and agrochemicals. Single crystal X-ray diffraction (SC-XRD) analysis is the most powerful technique for molecular structure determination. However, SC-XRD analysis requires good quality crystals. In fact, the biggest hurdle for SC-XRD analysis is crystallization.  Crystallization trials require a large amount of high-purity target compounds. Moreover, despite performing tedious and time-consuming trials, sometimes good quality crystals for SC-XRD analysis may not be obtained. In this case, we have to give up on structure determination. As one way to address this situation, Fujita et al. have reported the crystalline sponge method (CS method) for the structure determination of small molecules .

With this method, crystallization of the target compound is not required. The CS method uses a metal-organic framework (MOF). The target compounds are incorporated into the CS crystal by soaking and are oriented in the porous coordination network of the MOF. Then, the structure can be determined by SC-XRD analysis. As a result, the CS method allows the SC-XRD analysis of many compounds that cannot be crystallized. However, as with other analysis techniques, the CS method has some limitations. The method is not applicable to all types of compounds.

The CS method uses the MOF as the “container” for the compounds. Looking at CS method figures, we came up with a new idea—the container does not have to be an MOF. We wanted to prepare a container with the ability to bind to a wide variety of compounds; therefore, we focused on proteins because they can bind to organic compounds. Some proteins can bind to a wide variety of compounds, such as anionic, cationic and neutral compounds. Therefore, we started to develop a new crystalline sponge method that is different from the existing method.
 

For manufacturers who market a wide range of products, including household products, pharmaceuticals and/or nutraceutical products, it is important to communicate the characteristics of their products to consumers. This often requires a good evaluation technique that can show the product characteristics intuitively. X-ray imaging techniques, which can visualize the internal structure of a sample non-destructively, are now widely used in academic, medical, and industrial applications. The combination of X-ray and Computed Tomography (CT), which can re-construct the internal 3-dimensional structure of a sample through numerical computation of the transmission data, is called X-ray CT, which is used in a variety of processes, from R&D to quality inspection. Herein, we report an application of the X-ray CT technique for evaluating the performance of laundry detergents and how the results were successfully used for the promotion of a detergent product.