News
Winter 2010/11 - 23/02/2011
Welcome to the Winter 2010/11 Specac News Bulletin.
Our regular bulletin is here to keep you up to date with the latest news on all our new developments. You’ll also get a more in-depth look at some of the many products we offer, as well as advanced notification of the trade shows we’ll be attending. We are the World’s leading spectroscopic accessory manufacturer, producing the industry’s widest range of Lab IR sampling accessories for solids, liquids & gases. Our fully integrated sampling solutions work at temperatures from -190°C to 800°C, pressures from vacuum to 6000psi and under corrosive conditions that leave other manufacturers bewildered.
Specac are pleased to announce there is no price increase again this year - the 4th year running.
Despite rising costs in other areas we have managed to keep our end user pricing static once again meaning that our prices are still at 2007 levels, allowing your budget to go further.
In partnership with Systems Engineering in Japan we are pleased to introduce a new top-plate for the Golden Gate™.
The Envirochamber top-plate has been specially designed for analyzing hazardous samples.
The standard version has the sample area sealable within a Perspex chamber allowing hazardous samples for example, to be positioned on the Golden Gate™ top plate in a safe environment such as a fume cupboard or glove box and then sealed so the unit can safely be taken back to the spectrometer for analysis.
This new top-plate as standard comes with a diamond crystal but other materials are available upon request, in addition a heated version will be available.
Unfortunately in life, accidents happen. Things break or get lost and it can be a frustrating experience to replace them again, particularly if it is a special part that is required.
Specac have listened to our customers if they encounter these types of problems with our products and so to try and help, if certain key items get lost or misplaced, an Essential Spares Kit of parts is now included with the majority of our accessories, when the accessory is purchased from new. The ESK is also available for purchase at a later stage if required.
If a particular fixing screw, washer or O-ring, is lost or becomes damaged, it should be possible to have a replacement part to use immediately from the ESK of parts, such that there is a minimum time delay for getting the accessory back to its proper working condition again.
The accessories that are provided with their own ESKs as standard are:-
All Golden Gate™ Diamond ATR Accessories.
The Silver Gate™ Evolution ATR Accessory.
The Variable Temperature Cell and Cuvette Holder Accessories.
The High Temperature High Pressure Cell Accessory.
The Environmental Chamber for the Selector Diffuse Reflectance Accessory.
The Cyclone™ and Tornado™ Ranges of Long Pathlength Gas Cells.
Heatable, Sealed and Demountable, Static and Flow, Liquid Cell Assemblies
These kits will be available from January, please contact us for more information.
The Environmental Chamber (GS19930) expands the capability of the Selector Diffuse Reflectance accessory (GS19900) used for DRIFT Spectroscopy. The Environmental Chamber allows the analysis of solid and powder samples under a wide range of conditions, temperatures of up to 800°C and pressures from vacuum to 500 psi.
The Environmental Chamber is supplied with a ZnSe window as standard as part of the pressurised chamber assembly. It offers a good balance between IR transmission and mechanical strength, but other window materials are available upon request.
Safety features include low voltage (30 volts) automatic power supply with an automatic shut down feature should an over heating fault be detected. A pre-determined pressurised burst disc assembly is incorporated as standard in case the pressure exceeds the recommended safety limit.
The Environmental Chamber with the Selector accessory, is ideal for chemical research such as kinetics, catalysis, surface analysis, polymerization and co-ordinated chemistry.
Introduction
Asbestos is a generic term for a group of naturally occurring complex crystalline silicate minerals with fibrous characteristics. Since the start of the 20th century large quantities of these asbestiform minerals have been exploited commercially due to their excellent tensile strength, thermal stability, insulating, and chemical/weather resistant properties. They have been used in heating and electrical insulation, building construction, strengthening of mortars, and as plastic fillers (1).
The side effects, generally by inhalation of these fibres, in human beings and laboratory animals have been known since asbestosis was first reported in 1906 in English and French asbestos textile industry workers (2). Various forms of cancer and tumours attributed to asbestos are well documented. There are two basic fibrous forms - a phyllo-silicate/serpentine group e.g. chrysotile (white asbestos) which is the most abundant and the amphibole group comprising of several inosilicates e.g. amosite and crocidolite (blue asbestos).
The most lethal amphibole is crocidolite which has been prohibited in the UK by legislation since 1970 and currently most materials containing asbestos are made from chrysotile (3).
Several analytical methods including x-ray diffraction spectrometry, electron microscopy, polarised light, and dispersion staining microscopy and infrared spectrometry have been used to analyse and classify different forms of asbestos. Infrared techniques that may be employed are FTIR microscopy, transmission via KBr disc sample preparation, and diffuse reflectance spectroscopy
The latter has been chosen because of the advantages of low cost, minimal sample preparation of the potentially hazardous samples, and speed of the technique.
Experiment
For this application note, results were collected for with the use of Specac’s Selector Diffuse Reflectance Accessory, as shown in Fig. 1.
This accessory is specifically designed with an off-axis optical layout to selectively eliminate specular reflectance spectral components of the sample, as specular components are often found to distort reflectance measurements of many inorganic materials.
The accessory requires minimal alignment between sample changes. The FTIR spectrometer data collection conditions were set at 30 scans averages and 4cm-1 resolution.
The background spectrum was scanned using KBr powder as a reference. Samples of asbestos fibres were removed and compressed into a sample cup of the diffuse reflectance unit and spectrum collected.
Results and Discussion
The basic building unit of inosilicates has been recognised as (Si4O11)n and phyllo-silicates as (Si2O5)n. The frequency correlation and vibrational assignment of these structures have been determined4. The approximate molecular formulae are shown in Table 1.
The spectra shown in Fig. 2 correspond, in turn, to crocidolite, amosite, and chrysotile.
All the different forms show characteristic absorption bands due to various Si-O stretching (υs) and bending (υb) vibrational modes between 1200-800cm-1 and O-Si-O scissoring (δ) vibration below 650cm-1.
The region between 3200 and 2000cm-1 is featureless although some weak absorption bands attributed to hydroxyl groups can be found between 3700 to 3200cm-1 which have been used to characterize some asbestos (6), (7).
*Variable Fe2+/Mg ratio. The predominant element is placed first in the formula.
The diffuse reflectance spectra of the three asbestos forms (Fig. 2) show distinct differences enabling characterization of the various forms.
These differences are due to the influence of the different cationic groups, and proximity of the hydroxyl groups associated with the crystal lattice causing changes in band shifts and intensities.
The weak absorption bands occurring between 1700 to 1400cm-1 are attributed to the hydroxyl groups (chemically or physically bonded).
The broad hydroxyl absorption at 605cm-1 in chrysotile is absent in both amosite and crocidolite. Chrysotile may also be distinguished from the inosilicates by the absence of absorption bands between 950 to 750cm-1.
Crocidolite may be distinguished from amosite by bands at 870, 690, and 580cm-1 and the absence of strong bands at 1000 and 460 cm-1.
Conclusion
The diffuse reflectance infrared Fourier transform (DRIFT) analysis and classification of asbestos fibres gives quick and reliable results without elaborate handling and preparation of these carcinogenic fiborous materials. The potential problem associated with the KBr disc technique of production of non-isotopic samples from fiborous materials is also eliminated.
The DRIFT method is relatively inexpensive, and requires less technical skill when compared to microscopy techniques. The Specac Selector Diffuse Reflectance Accessory may also be used to analyse asbestos dust filtered on to a filter paper without prior preparation due to it’s off-axis design.
References
1. Bates, R.L., “Geology of the Industrial Rocks and Minerals”, Dover Publications Inc., New York, N.Y., 1969.
2. Rowe, W.F., McLane, A., International Laboratory, pg 20, March 1989.
3. Coates, J.P., Perkin Elmer Application Note No. IR141.
4. Lazalev, A.N., “Vibration Spectra and Structure of Silicates”, Plenum Press, New York, pp110-112, 1972.
5. Ed. Davis S., “Biological Effects of Asbestos”, IAAC Scientific Publications, W.H.O., No. 8, pg1073, Lyon 1972.
6. Farmer, V.C., The Infrared Spectra of minerals, pp306-330, Mineralogical Society, Monograph 4, 1974.
2011 has arrived and once again the Specac team and products will be visiting trade shows around the world, below are the shows we have confirmed so far for 2011. To keep up to date with where we are when please visit our website.
The premier spectroscopy show in the USA will soon be here again. Specac will be in attendance with a wide range of our products including our newest products for you to see. Members of our sales and technical support teams will be on hand to answer your questions and give you any support you need.
Come and see us at booth 2260. If you would like to arrange an appointment with a member of our team please contact us at reach@specac.co.uk
October sees the return of China’s BCEIA show in Beijing, following the success of the 2009 show Specac will be retuning to China in October for the 2011 version. On display at our booth will be a wide range of our products including our new developments. Also on hand will be members of or sales and technical support teams to provide any help and support you need.
Our booth location has yet to be published but when it is we will have it listed on our trade shows webpage.
We are updating our 2010 product catalogue and we will release the 2011 version very soon, please look out for it. To be one of the first to receive the new issue please send us your details to (reach@specac.co.uk)
Our technical experts are always willing to help our customers with their technical queries and issues. The team can be contacted via the "Technical Support" section of our website or by email: techsupport@specac.co.uk
