The Interpretation of Infrared Spectra
The annual four day intensive course on the Interpretation of Infrared Spectra will be held 8 – 11 November 1999.
Participants will concentrate on practical interpretation of infrared spectra for the majority of the course, being guided though many examples of both typical and a-typical spectra. Building on a foundation of generating and using correlation tables on day one, the student will progress through a comprehensive set of fundamental group vibrations, and by the end of the course will have achieved a good working knowledge of spectral interpretation.
This course also includes a brief resume of basic infrared theory and a presentation on computer methods used in interpreting and matching infrared spectral data. Many people have benefited from this course in recent years.
For further details contact Monica Pope at Perkin-Elmer Ltd.
Training Courses – Infrared Spectroscopy
Perkin-Elmer holds a series of training courses throughout the year in the training centre at Seer Green, Buckinghamshire. Dates for courses up to June 2000 are now available.
Available courses include:
Introduction to Infrared Spectroscopy
Advanced Infrared Spectroscopy
Sampling Techniques for Infrared Spectroscopy
Interpretation of Infrared Spectra
Quantitative Analysis (Basic and Advanced)
Courses can also be held at users sites.
For details contact Monica Pope at Perkin-Elmer Ltd
The LabRam Infinity
The Next Generation in Analytical Raman Microscopes
The application of Raman spectroscopy in the analytical laboratory has now become a more common place event and with the introduction of new technologies such as CCD detection and holographic laser rejection filters the dispersive Raman microscope has become a truly bench-top tool.
Introduction to Raman Microscopy
Instruments SA and its group divisions of Jobin Yvon, Dilor and SPEX developed the first commercial Raman microprobes in the early 1970’s (1). Since then the technique has been refined and developed to provide an essential method for micro analysis (2).
The Raman microprobe, based around the well characterised principles of the confocal pinhole and coupling optics (see Figure 1.) can provide the very highest spatial resolution – The latest systems can now reach close to the theoretical diffraction limit and typically analyse particles as small as one mm. When a motorised X,Y,Z stage is used, a full confocal Raman mapped image can be generated – invaluable to studies of dispersed particles and surface structure (see Figure 2.)
Figure 1.The Confocal Principle for a confocal microscope can be applied to the Raman microscope. The energy from a point on the sample irradiated by a laser is focused onto a spatial filter, the confocal hole (c.h.) and is detected by a detector D. With a confocal hole, only the energy generated by a point in the plane P is detected. The energy derived from a plane P’ or P’’, is not focused on the confocal hole and is rejected( and not detected). This is the principle of the confocal microscope. Replacing the simple detector by a spectrometer system gives the basis of the dispersive Raman microscope
Figure 2. Raman mapped image of explosive particles dispersed over a surface. Generated from a confocal XY map using 633 nm laser excitation.
The LabRam Infinity
It has long been the case that although the possible capabilities of the Raman microscope have proved attractive, Raman systems and in particular Raman microscopes have been often difficult in their operation and with only a fixed and inflexible configuration. As with all Raman instruments there are often many competing effects and processes that can have a great bearing on the quality of the data obtained. Fluorescence, sample heating, photo degradation, weak scattering efficiency can all produce adverse effects on the Raman spectrum. The limitations imposed by fixed configurations has led to the development of instruments which set out to solve these problems by offering flexible instrumentation where the laser source, laser power and resolution are easily adjusted to suit the varied samples found in the routine analytical and development laboratory.
The LabRam Infinity Raman system (Figure 3.) has been specifically designed to give the analytical laboratory a lower cost yet high performance Raman microscope. One that also meets the flexibility and operational requirements demanded by the modern analytical laboratory. The aim being to provide the widest range of highly specific analysis of solid, liquid and solution samples that this technique can potentially offer to the analyst.
Figure 3. The LabRam Infinity from Instruments SA- Horiba Group
Flexibility is the Key
Within the unique optical design of the LabRam Infinity it is possible to incorporate features and facilities traditionally only found on larger high-end research instruments. The single chassis design also provides the ultimate in stability and so removes the need for any optical adjustment or alignment essential for a system that is to be used for fast routine analysis.
The new Dual laser models offer two laser sources mounted internally. The advantage of having multiple laser sources and not just a single laser line is well known. For instance, with the 532nm/785 nm dual option, high scattering efficiencies are provided by the green laser , whilst switching over to the NIR 785 nm diode laser enables the user to often avoid fluorescence problems (Figures 4 and 5.). Other configurations, including HeNe and even UV laser sources can also be accommodated on such an instrument truly offering an unprecedented versatility.
Figure 4. Raman spectrum of DLC (Diamond like carbon) with 532nm laser.
Figure 5. Raman spectra of an Industrial polymer with 532nm (top) and 785 nm(below) laser excitation
To add further flexibility, the LabRam infinity has dual gratings incorporated in the instrument. Again, a well established advantage of the research grade instruments was to have the ability to change diffraction gratings. Hence, this could enable the user to select different spectral resolutions. For example, to offer Raman spectra with a high resolution grating and to offer a broader fluorescence spectrum with a lower resolution grating. Moreover, if multiple lasers sources were to be used the instrument could have gratings optimised for performance in different regions, say 488 nm and 785 nm. (Figure 6.)
Figure 6. Typical Efficiency Curves for Visible (blue trace) and NIR (red trace) optimised gratings
The Dual gratings used in the LabRam infinity now give this same versatility to the bench-top instrument.
In addition to flexibility, a further prerequisite for the analytical instrument is to be able to operate the system with the minimum of effort and maximum of ease. The next generation of Raman microscopes such as, the LabRam Infinity now offer a very high level of automation. The Infinity is a truly unique ‘turnkey’ system where the selection of different lasers, spectral coverage and other facilities is all automated and requires no user intervention. To switch gratings or lasers is now trivial and accomplished in seconds by computer command.
Laser (operator) Safety
All this sophistication and flexibility is very fine but if the instrument is confined to a laser laboratory with restricted access, then its usefulness is greatly reduced. For this reason the LabRam Infinity was designed to meet class (I) laser safety protocols. The integral laser safety frame and tiered password protected software means that the inexperienced user is totally isolated from the laser sources. Of course, for the ‘Raman traditionalist’, or those users with large format cryostats the system can be operated with the frame open, provided they have the correct security password.
In summary, the LabRam Infinity represents the next generation in analytical Raman microscopes. It offers the very highest level of performance and versatility, whilst its integrated and automated design means this system is regarded as almost a ‘black box’ instrument.
- P Dhamelincourt, University of Lille, Doctoral thesis (1979)
- “Confocal Raman Imaging” ISA publication
For Further Information on the LabRam Infinity or any of the Raman instruments in the ISA range. Please contact
|UK and Ireland
Instruments SA UK
2-4 Wigton Gardens
HA7 1BG Tel : 0181 204 8142
Fax: 0181 204 6142
Email : mailto:Sales@isa-gs.co.ukWebsites : http://www.isa-gs.co.uk
|Instruments SA Inc.
3880 Park Avenue
Edison, NJ 08820Tel : 1 732 494 8660
Fax 1 732 549 5125
The Chemistry and the Internet (ChemInt’99) meeting being held in at Georgetown University in Washington DC on September 25-27, 1999. Poster abstract are still being accepted. To date 24 have been accepted. September 1 is the final deadline for poster abstract submissions.
The program of invited speakers and panel members of the 3 panel sessions is available on the meeting web site – www.chemint.org
You are urged to look at the program and to consider submitting a poster paper to the meeting.
The main lecturers for the meeting will be:
Alan Arnold, University College (UNSW)
Steven Bachrach, Northern Illinois University
Robert Bovenschulte, ACS
Stephen Boyer, IBM
Karl Harrison, Oxford University
Clemens Jochum, Deutsche Bank
Gary Mallard, NIST
Tom Pierce, Rohm & Haas
Jerome Reichman, Vanderbilt
Achim Zielesny, Bayer AG
Steven S. Zumdahl, University of Illinois at Urbana-Champaign
The (current) corporate sponsors for the meeting are
Technical Sponsors are:
ACS CINF Division
ACS COMP Division
The Chemical Structure Association (CSA)
Georgetown University – Department of Chemistry
International Union of Pure and Applied Chemistry (IUPAC) (pending)
Japan Association for International Chemical Information (JAICI)
Special Libraries Association (SLA) Chemistry Division
Royal Society of Chemistry (RSC)
Steve Heller, Guest Researcher
NIST/SRD, Mail Stop: 820/113
820 Diamond Avenue, Room 101
Gaithersburg, MD 20899-2310 USA