10th May 2006 MEETING ABSTRACTS

Morning Session

 
The tour (in two groups) will take in the main XRF laboratory with Energy and Wavelength dispersive systems and the new mobile laboratory with both bench top EDXRF and handheld EDXRF systems.

 
A wide variety of materials are used in the production of modern polymers. The manufacturing process involves catalysts, raw materials, additives and finally the finished plastic products. This process leads to a diverse array of sample types that pose a challenge to the XRF analyst. This keynote lecture addresses each stage of manufacturing and gives details on analytical and sample preparation techniques that have been developed to meet the challenge. Techniques for samples such as powders, plastics, pressed pellets and fusion beads will be examined.

 
Measurement of uncertainty is very important in method development and validation. This session begins with a review of some sources of help and advice on this topic, such as the EURACHEM/CITAC guide and BS EN ISO 12677:2003. Some practical examples from the wide variety of matrices analysed at LSM will be briefly outlined to lead into a discussion session on the topic.

Afternoon Session

 
Silver determination in photographic emulsion is a critical measurement within the industry. It has traditionally been done by titration with thioacetamide. An EDXRF technique is described here, which gives acceptable precision and avoids the toxic hazards associated with the titration method.

 
Corus as an international metals company provides steel and aluminium products to customers worldwide. Two years ago Chemist Committee Knowledge Exchange Groups (or CCKEG groups for short) were created in three main analytical areas XRF, OES and Wet chemistry. My presentation covers the work carried out by the XRF CCKEG and the exchange of best practices from four different Corus sites.

 
The presentation summarises some of the major coatings activity in the National High Temperature and Surface Engineering Centre at Cranfield University. The application of XRF, using an S2 Ranger multisample system is discussed. Specific areas demonstrated are materials for aerospace gas turbine applications such as, zirconia-based ceramics used for thermal barrier coatings, superalloys and bond coats. Particular emphasis is made as to the importance of analysis of trace elements in the materials, the concentrations of rare earth oxide dopants and their importance in thermal barrier coating technology. Some of the coating process technology will be presented and the use of XRF to monitor the output of processes.

 
Many workers (e.g. Henderson et al., 2004), including ourselves are currently carrying out provenancing studies of ancient glasses by means of a variety of chemical analysis techniques including, XFR, LA-ICP-MS and EPMA followed by the application of statistical analysis. Differences in raw materials and manufacturing techniques manifest themselves as variations in the chemistry of the final glass.It is these differences e.g. sand used as a silica source as apposed to quartz, than enable the differentiation of a glass made at one site from another.

 
Forensic analysis of glass (e.g. window glass) is often used to connect suspects with crime scenes.At present 35% of container glass in the UK is recycled and 80 – 90% in Europe (www.britglass.org.uk). It may be that this form of glass is now more difficult or impossible to provenance because of recycling.Glasses from different parts of the world are exported and may be recycled with lots of other glasses manufactured elsewhere.

 
We have carried out a small study to investigate the provenancing of wine bottles. X-Ray Fluorescence Spectrometry (XRF) has been used to distinguish between the locations where modern glass bottles were manufactured. By analysing glass bottles for their trace element contents, and subsequently applying statistical analysis in the form of PCA (Principal Component Analysis), it may still be possible to discriminate between modern bottles made in different locations (see Fig. 1).

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Figure 1.
PCA analysis of XRF data for 33 green wine bottles. Henderson, J., McLoughlin, S. D., and McPhail, D. S., (2004). Radical changes in Islamic glass technology: evidence for conservation and experimentation with new glass recipes from early and middle Islamic Raqqa, Syria. Archaeometry.46 (3), 439-468.

 
General Use Materials (GUMs) are routinely analysed by time consuming and complex instruments (such as titration and ion chromatography) to perform relatively simple identity testing. It is desirable to simplify and speed up this process.

A PANalytical Minipal4 EDXRF spectrometer was evaluated for this purpose using several inorganic compounds from the GUMs list. This instrument is a relatively small, simple, low cost spectrometer. The XRF technique is inherently simple and quick and requires virtually no sample preparation.

The compounds tested can be identified qualitatively by overlaying with reference spectra but this does require some expert knowledge in interpreting the spectra. The main technical objective of the evaluation was to establish the basis of a method that could reliably distinguish between compounds using a quantitative approach. This method should be suitable for relatively inexperienced operators with very little need to interpret the spectra.

 
Glass is a material that has been around for thousands of years and while remaining commonplace in everyday life, glass can still be found at the leading edge of technology. The chemical composition of glass has a direct impact on the properties of the material, this will influence its technical and physical properties so accurate analysis of the composition is vital.
The presentation will encompass glass formation, production and physical properties. GTS works with glass manufacturers all around the world and is uniquely placed to offer solutions to technological problems.
Prime amongst these is the issue of glass colour caused by low level contamination of the raw materials, cullet and from the furnace itself. GTS is developing method for analysing the majority of trace colourants commonly found in glass in order to help customers solve problems. Allied with this is the development of specialist drift correct glasses for the use with XRF instruments containing detectable quantities of multiple elements.