Volume 35(1) - Winter 2019

The discovery of graphite and its industrial use dates back to the 16th century, more than 200 years before the first industrial revolution, which took place from the middle of the 18th to the 19th century. The first industrial use of graphite was as pencil lead and fire-retardant materials. It is now used in a variety of high-tech fields, including nuclear energy. More than 1.2 million tons of graphite is produced each year, with an upward trend foreseen in future demand.

Graphite is inexpensive and distributed throughout the world. Sufficient reserves exist to meet demand for hundreds of years, according to verifiable sources. The existing supply of graphite is almost infinite. Once a flake of graphite is peeled off, it becomes a fascinating material called “graphene,” a stunning discovery that did not occur until 2004. Graphene is 1,000 times stronger than iron steel, exhibits more than 10 times higher electrical and thermal conductivity than metals, and is the thinnest and lightest flexible material known today. In 2010, the Nobel Prize in Physics was awarded for its discovery.

Innovative materials and products can potentially be created in various fields using graphene. Therefore, research institutes and companies all over the world conduct research and development into practical application of graphene in almost every industrial field. In the years since its discovery, products such as electronic items, acoustic products, daily commodities, tires, golf balls, sportswear and shoes have been developed, making use of graphene for improved impact strength, conductivity characteristics, and so forth.

However, reasonably accurate measurement methods, analytical methods, definitions, standard references etc. have not been developed to identify graphite or graphene qualitatively or quantitatively. Graphite and graphene are currently evaluated in a limited, subjective, speculative way by shape observation using an electron microscope, surface analysis using Raman spectroscopy, a specific surface area measurement by gas absorption and so forth. The purpose of the Graphite/Graphene Analytical Index presented here is to exhaustively identify and characterize graphite, graphite-based graphene intermediates and bulk graphene, and to significantly enhance the efficiency of research and development related to these materials. Furthermore, we hope this index accelerates the development of breakthrough products based on graphite and graphene.

Since the earliest experiments, X-ray crystallographers became accustomed to directly observing reciprocal space. Initial experiments were performed using area detectors with photographic film as the detection medium. While accurate measurement of diffracted intensity was not possible, observing the space around reflections was. Initially experiments used flat arrangements of photographic film though since X-ray crystallography experiments involve diffraction outward in all directions from a point, the crystal, it wasn’t long before curved, cylindrical X-ray cameras were developed which more closely matched the spherical nature of diffraction experiments. With proper alignment of the crystal, this technique allowed observation of reciprocal lattice planes and lattice lines, measurement of unit cell dimensions, observation of systematic absences and observation of spurious intensities. Regardless, with photographic film glimpses of space between Bragg diffraction could be seen. With the advent of electronic area detectors and computerised measurement, it became possible to achieve even better views of reciprocal space. With modern diffractometer equipment and software, sampling and viewing reciprocal space in its entirety in three dimensions is now possible in short timescales. Ewald^3D is a module within CrysAlis^Pro which allows not only reconstruction of reciprocal space in three dimensions at the end of a data collection but also offers a live view of data as it is still being collected.

Recently, products development, failure analysis of electronic devices and quality control requirements has increased demand for X-ray CT 3D image viewing analysis. Powerful CPUs and GPUs have greatly improved computer processing throughput for this technique.

Rigaku has been contributing to the fields of drug discovery and development, preclinical testing, and animal diagnosis since releasing a 3D X-ray micro CT for laboratory animals in 2006 and a CT for animal hospitals in 2013. In 2015, Rigaku launched both the “nano3DX” sub-micron-level resolution X-ray microscope and the “CT Lab GX” industrial materials analysis 3D X-ray micro CT. Since then, Rigaku has been providing nondestructive 3D materials structure analysis solutions and failure/dislocation analysis solutions for electronic devices, resins, and so on.

“CT Lab HX” is a benchtop 3D X-ray micro CT for wide FOV (Field of view) and high-resolution imaging and more, developed by taking advantage of Rigaku’s unique CT engineering experience developing 3D X-ray micro CT instruments for industrial materials analysis. “CT Lab HX” is a versatile CT system, having applications as diverse as examining electronic devices and metal casting, to merchandise inspection and performance tests, to basic research and development in medicine and medical treatment, to industrial applications for examining resin, bones, minerals, and so on.

As a handy and quick elemental analysis technique, X-ray fluorescence spectrometry is widely used in many industrial fields. It should be noted that energy dispersive X-ray fluorescence (EDX) spectrometers provide opportunities for miniaturization, because their system configuration does not require a dispersive element or goniometer. In addition, because of their ability to analyze multiple elements simultaneously, these spectrometers demonstrate their superiority especially when a sample of unknown identity needs to be analyzed quickly. One of the best examples of this is analysis of foreign materials mixed into products. 

In recent years, safety awareness is increasing among consumers. If by any chance a foreign material is spotted in a product after shipment, the product manufacturer will be required to analyze the foreign material and to identify the route of contamination quickly and accurately. There are several types of techniques used for analyzing such foreign materials, but EDX spectrometers are excellent, especially in handiness and promptness, and are considered best suited for this type of analysis.

In this report, methodologies associated with analyzing foreign materials, using NEX DE energy dispersive X-ray fluorescence spectrometer, will be described. In addition, several examples of analyzing specific foreign material samples will be described.

Sensing odors is an extremely important ability humans have as living organisms. This ability is required for humans to maintain appropriate eating behavior and to protect themselves from imminent danger. The term “odor” includes naturally occurring odors from food and flowers, and artificial odors from synthetic essences, as well as a variety of other smells.

Humans sense odors when they inhale airborne molecules through their nostrils. Based on this fact, odors basically consist of volatile substances (compounds). In order to learn what the molecular structure of trace amounts of volatile odor components is like, many studies and analyses have been conducted for many, many years across different technical fields. 

The human sense of smell can even sniff out optical isomers. In the case of limonene's optical isomers , whereas the d-isomer has the refreshing smell of citrus fruit, the l-isomer has the smell of petroleum. When substances with an identical composition formula but a different 3D structure are floating in the air, humans sense these substances as totally different odors. This is because sensing an odor starts with the coupling of an odor molecule with a G-protein coupled receptor (GPCR). The state of the coupling varies depending on the shape of the odor molecule, including with which GPCR the odor molecule can couple (from reportedly over 800 kinds of GPCR), at which part of the GPCR, and how tightly. It is believed that this accounts for the uniqueness of odors.

Therefore, just as the molecular structure of a pharmaceutical compound (including its absolute configuration) is important when it works as a “drug,” the odor’s molecular structure is considered to play a critical role when an odor is generating the intended sense of “fragrance.” An extremely low concentration of an odor component can react with the receptor in the human nose in the form of odor, which means that only a trace amount of such a component exists in the environment. For this reason, if you want to extract a specific odor component from natural raw materials for analysis, you may end up obtaining only several micrograms or less from a large quantity of raw material (in the range of several kilograms to several tons). This is why gas chromatography (GC), liquid chromatography (LC), and mass spectrometry (MS) are widely used today as mainstream analytical equipment capable of analyzing extremely small amounts of samples. However, even with the help of these analytical techniques, directly determining the 3D molecular structure of odor components is impossible.

On the other hand, single crystal X-ray structure analysis is suited for the determination of the 3D structure of hitherto unknown substances. However, this analytical technique requires large quantities of high purity samples for crystallization, and for this reason it has seldom been used for the analysis of odor components in the past. The emergence of the crystalline sponge method has dramatically changed this situation.

This report introduces examples of our attempts to analyze the structure of odor components, in which volatile substances emitted from natural products are directly trapped without the isolation of odor components or sample preparation, using the “crystalline sponge method”, a single crystal X-ray structure analysis method that does not require sample crystallization.

In our previous report, we introduced the concept of GI-XRD (grazing-incidence X-ray diffraction) with a 2-dimensional (2D) detector for thin film samples. However, it seems we have not fully explained how well a 2D-SAXS/WAXS (reflection) attachment works in GI-XRD with a 2D detector.

So, we decided to briefly review the usefulness of this attachment together with up-to-date applications of functional thin films by GI-XRD using a HyPix-3000 2D detector with this attachment.

In a crystal, atoms or molecules are arranged in a three-dimensional, repetitive pattern, and the properties of the crystal are determined by the chemical composition of the constituent atoms or molecules. The typical image of a crystal is a grain of a single crystal such as salt or alum, but many familiar materials, such as metals, ceramics, and crystalline polymers, are solids composed of microcrystals. These are called polycrystals, in contrast to single crystals. There are cases where the texture and crystallinity of the crystals constituting the material at larger scale are related to properties such as the strength and hardness of crystalline materials composed of a polycrystal.

Evaluation of crystalline polymer materials in powder X-ray diffraction is roughly divided into analysis of the small angle X-ray scattering (SAXS) region, corresponding to a long-period structure of about 1–100 nm, and analysis of the wide angle X-ray scattering (WAXS) region, corresponding to an atom-to-atom interval on the order of 0.1 nm (1 Å) . The fact that evaluation must be done by combining the SAXS and WAXS regions when considering the structure and properties of crystalline polymer materials is a point of difference from the evaluation of inorganic materials.

Cases have been reported, including in this journal, where measurement in the WAXS region was carried out via scanning with a 2D detector(1)–(3), but there are no reports of exposure measurement using transmission. This paper presents examples of analyzing polypropylene (PP), polyethylene (PE), and polybutylene terephthalate (PBT) with measurements carried out using the SmartLab fully-automated multipurpose X-ray diffractometer and the 2D-SAXS/WAXS transmission attachment.

Cement is one of the most essential materials in modern construction. In this article, the term “cement” means Portland cement, which is typically a grayish powder to be solidified by a hydration reaction. Portland cement comprises most of the total cement production.

The cement manufacturing process is composed of three basic steps: raw meal preparation, clinker production and cement milling. In the raw meal preparation process, raw materials such as limestone, clay, shale, silica sand and iron oxides are blended together in suitable proportions to make raw meal. During the clinker production process, preheated and precalcined raw meal is fed into a rotary kiln for sintering at up to 1450°C to form clinker minerals, then the hot clinker is cooled. In the cement process, small quantities of gypsum are added to clinker. They are then milled together to make final cement products.

Production of uniformly high-quality cement requires advanced process control and blending quality based on accurate chemical composition obtained by prompt and reliable chemical analysis methods.

Total reflection of X-rays occurs on the surface of a measured object by X-ray irradiation at an extremely low glancing angle (less than 0.1°). X-rays penetrate into a measuring object to a depth of only several (≈10) nm. Therefore, elements on the surface of the sample carrier are excited efficiently and the background intensity occurring from the sample carrier is extremely low. As a result, spectra with high S/N ratio can be obtained. High-sensitivity analysis for trace elements on the surface of the sample carrier can be performed by the total reflection method with a total reflection X-ray fluorescence (TXRF) spectrometer. Concentrations of μg/L (ppb) for inorganic components in a water sample are easily determined by using the internal standard method. Analysis results of beverage samples (drinking water and soft drink), milk, coffee, tea and wine by TXRF are reported. Many more TXRF results of serum samples by acid decomposition are also reported(3). Recently, TXRF spectrometry is widely used for liquid analysis because TXRF spectrometry was made an official liquid analysis method by the International Organization for Standardization (ISO). In this paper, water analysis by TXRF is described and, beverages and serum are introduced as analysis examples.