14June2017

XRF Meeting Report 14^th June 2017

A joint BCA/ RSC Atomic Spectroscopy Group Meeting at University of Leicester.

The meeting took place at its usual venue, the Geology Department of the University of Leicester. 46 delegates attended. After the welcome and introduction, the meeting got under way with the Exhibitors’ Forum. This is an opportunity for each of the exhibitors to present a quick-fire overview of their latest XRF-related developments. Each exhibitor was allowed 4 minutes: Nick Marsh acted as referee.

Session 1 Morning Speakers.

Front row - Frederick Davidts (XRF Scientific), Dave Speake (SPEX Europe), Jennifer Horner (Spectro), Ros Schwarz (DOT round up), Allan Finlay (Specac Ltd), Nick Marsh (chair), Tom Warwick (Blue Scientific)

Back row - Mike Brogan, (PANalytical,) Jan Roms, (Thermo Fisher,) Ralph Vokes, (Shimadzu), Chris Calam, (Thermo Fisher Scientific), Thierry Theato, (Spectro), Paul Vanden Branden, (SciMed), Adam Housley, (Datech Scientific Ltd).

Session 2 Morning Speakers.

Thierry Théato (SPECTRO), Frédéric Davidts (XRF Scientific) and Judith Bain (Chair).

The rest of the morning session is reported by Oli Williscroft (University of Hull and Intertek).

I found one of the most interesting talks of the day was given early on by Dr Ros Schwarz and her DOT scheme results. Each meeting Ros has encouraged participants to partake in analysing her unknown samples that contained a few surprises with elements not typically seen at significant concentrations for most routine work. Ros’s results showed that without carefully approaching unknown samples it is very easy to introduce significant errors to the results with one of her samples containing a high concentration of bromine that enhanced the line of another element of interest leading to inaccurate results for both elements. Furthermore Ros spoke about the differences between XRF and ICP for trace elements and how below certain concentrations results from XRF become far less precise than those from ICP.

The second talk of the day was given by Dr Tony Bell from Sheffield Hallam University. Tony’s talk focussed on the advantages of the two analytical techniques WD-XRF and XRD, and how they can be incredibly complementary when unknown samples are to be analysed in the lab. Data obtained from one technique can then be used to ‘feed’ the other technique allowing rapid analysis by reducing the number of possible compounds. In Tony’s university lab where students’ time on equipment is limited it allowed faster analysis of the students’ ceramics giving information on the overall composition from XRF as well as the individual silicates from XRD.

Kevin Talmage from Rigaku gave an interesting talk on the use of online XRF analysis for process control. Many companies seek ways to ensure that their production line stays within their control limits without the need for time consuming, slow, costly lab analysis. By installing XRF equipment directly on the production line, often in very challenging environments, Rigaku products allows the process to be continually monitored. One example of this was the control of sulphur content in an oil refinery process, and the challenges the Rigaku team had to overcome for the development of this process monitoring equipment.

Thierry Théato from SPECTRO Analytical Instruments delved into the realm of classical fundamental parameters (FP) and its usefulness for the analysis of small unknown samples. In many labs it is common to receive a large range of unknown samples for which a calibrated analysis isn’t practical, in these cases many labs turn to the use of ‘standard-less’ analysis through the use of the FP model. Thierry showed that the measured intensity of samples below the critical depth can have a significant impact on the calculated concentration for organic and oxide samples. Furthermore we all know that for samples in a light matrix analysis can be difficult when the sample thickness is less than the critical depth. Thierry also demonstrated that modifications to the fundamental equations in their newest EDX equipment allowed far more accurate analysis of sulphur and other trace elements in used vegetable oil.

Some Afternoon Speakers

From Left, Joanna Collingwood (University of Warwick), Thierry Theato (Spectro), Kenneth Harris (Cardiff University), David Beveridge, (Chair), Tony Bell (Sheffield Hallam University)

The first afternoon session is reported by Dr David Beveridge (HARMAN technology Ltd).

In the first afternoon session, Professor Kenneth Harris of Cardiff University spoke about validation is structure determination from powder XRD data, and how synergies between techniques could be exploited to this end. Structure determination of organic materials directly from powder X-ray diffraction data is nowadays carried out extensively in both academia and industry. The most common approach is to exploit the direct-space strategy for structure solution followed by Rietveld refinement. It is essential that the structural results thus obtained are scrutinised rigorously to ensure that they are correct. He discussed several aspects: validation of the correct structural model for use in direct-space structure solution calculations; and validation of the final structure obtained from Rietveld refinement. Particular care is taken in locating hydrogen atoms, for which solid-state NMR is useful. Synergistic use of information obtained from a variety of techniques is an important part of validating a structure.

In the second talk of the session, Dr Rainer Schramm of Fluxana spoke about the use of platinum-free crucibles for fusions. Pt/Au crucibles are commonly used for producing beads by fusion, but samples containing metallic or sulphide-rich particles can attack the crucible material and may actually destroy it. The best alternative is to use quartz crucibles; a research study of the analysis of steel-industry slag samples for 14 elements was successful. To oxidise metallic particles, an oxidising agent was added to the flux.

The final talk of the session was given by Dr Joanna Collingwood of University of Warwick, who spoke about the use of XRF techniques to investigate the interplay between iron and amyloid in Alzheimer’s disease. There is a long-standing debate about whether incompletely-bound reactive iron contributes to toxic processes in such brain disorders. The vast majority of mineralised iron in the brain is normally in a ferrihydrite-like FeOOH form, encapsulated in the protein ferritin. Synchrotron-source XRF was used to show the presence of magnetite (Fe₃O₄) in a region of the human brain exhibiting significant Alzheimer’s disease pathology in the form of amyloid plaques. Evidence for the formation of magnetite was also found in a transgenic model of Alzheimer’s disease that overproduces amyloid. A complementary set of synchrotron spectromicroscopy techniques, including XRF, allowed them to demonstrate with excellent chemical sensitivity and specificity that both unbound and mineralised iron is chemically reduced at physiological pH to a reactive form when in the vicinity of the aggregating amyloid protein. The suspicion is that this process explains the observation of magnetite in amyloid-rich brain tissue, and that it contributes to the observed toxicity of aggregating amyloid peptides in the brain infected by Alzheimer’s disease.

More Afternoon Speakers

From Left, Keith Tame (SciMed), Mike Dobby (Consultant), Ros Schwarz (Chair), Raphael Yerly (Thermo Fisher Scientific) and Graeme Hansford (University of Leicester)

The final session is reported by Judith Bain (Alfred H Knight).

The last session of the day mixed some manufacturing advancements with some excellent advice on how to use certain tools for your industry. The experience of these speakers was evident as the techniques Mike Dobby (now a consultant) discussed showed that there is a great deal of information often overlooked in a spectrum. The use of diffraction peaks can be useful qualitative information.

Keith Tame of SciMed continued this theme, talking of his experience in putting together XRD and differential scanning calorimetry (DSC) as useful combination research tools, particularly for investigating thermal reactions of solids. Some delegates had differing experience on this, which was interesting to talk through.

The final talk of the day I found very interesting, showing some real initiative. Dr Graeme Hansford of the Physics & Astronomy Department at University of Leicester described his work, taking a handheld EDXRF instrument and applying back reflection geometry to provide phase composition data on various metal alloys. Many uses came to mind for this as fundamentally producing a handheld XRD instrument opens up some interesting applications for the future. Phase identification and composition, and even texture data, can be obtained in the field.