ANALYTICAL INSTRUMENTS

Nuclear Magnetic Resonance Spectroscopy

The NMR is a powerful tool for the analysis of sequence, conformation, and other molecular attributes of biologically significant molecules, organics, and polymers, and also in the rapidly expanding areas of organometallic and inorganic NMR.  Kinetic and dynamic studies can be done on nearly all NMR active elements.  Both 1-D and 2-D experiments are now offered including:  INEPT, DEPT, carbon-carbon coupling detection (INADEQUATE), COSY, NOESY, ROESY, TOCSY, HMQC/HSQC/HMBC, and many others.

Two modern NMR spectrometers are operational:  a Varian Mercury 400 MHz NMR with autosampler capabilities for routine organic work and a Varian ^UnityINOVA 500 MHz NMR with inverse probe, broadband probe and a Varian nanoprobe which is an HRMAS (High Resolution / Magic Angle Spinning) probe with the capability to examine samples as small as 40 mL.  This probe can be used for swelled polymers, on-bead combinatorial work, oligosaccharides, and other biologics.

Ultraviolet-Visible-Near-Infrared Spectrophotometry

The Cary 500 UV/Vis/NIR Spectrophotometer covers the wavelength range of 3300 nm (near infrared or NIR) to 175 nm (ultraviolet or UV) with an accuracy of 0.1 nm in the UV/Vis range and 0.4 nm in the NIR range.  This instrument uses a double beam, double out-of-plane Littrow monochromator and dual double-sided gratings with up to 3 sources.  Detection in the UV/Vis range is with a high performance R928 photomultiplier tube and, in the NIR, with a low noise, electrothermally-controlled PbS photocell.  Spectral bandwidths from 0.01 - 5.00 nm (UV/Vis) and 0.04 - 20.0 nm (NIR) are possible.  Signal averaging is available from 0.033 to 999 seconds and scan rates up to 2000 nm/min (UV/VIS) and 8000 nm/min (NIR).  Accessories currently include:  square cell and cylindrical cell (gas and liquid), as well as a variable-angle reflectance (VASRA) accessory and highly-adaptable, solid-sample holders for films, blocks, slides, and membranes.

Infrared Spectrometry

The Nicolet 205 FTIR is a general-purpose, computer-controlled instrument designed for easy operation.  The resolution of the spectrometer is 2 cm^-1, and the spectral range is 4800 to 200 cm^-1.  The sample chamber and optics are purged with air with a dew point of -95^oF. 

Optical Rotation

The Rudolph Research Autopol III polarimeter is capable of measuring the absorbance of strongly absorbing compounds at 589 nm (sodium D line).  This instrument may take either 1 dm cells (10 mL solution) or 0.10 dm cells (5 mL solution).  Balancing of optical rotation is automatic, as is sample absorbance by simultaneous compensation with automatic gain control.

X-ray Photoelectron Spectroscopy

The Kratos Axis HS XPS (X-ray Photoelectron Spectroscopy) system offers surface analysis, surface chemical mapping, and depth profiling of metallic, semi-metallic, and nonmetallic samples as deep as 1 nm.  The sample is evacuated to 10^-9 Torr or better, for quality measurements.  The system is designed around a 127 mm mean radius hemispherical analyzer, which is equipped with a triple channeltron detection system for improved sensitivity.  By using a magnetic immersion lens, high sensitivity is apparent on small analysis areas.  A standard feature is XPS Imaging, which goes down to the 30 um level.  The charge neutralization system allows high resolution spectra to be obtained from insulating materials such as polymers using either the standard Mg/Al source or the Al monochromatic source.  The instrument is controlled by the VISION data system, on a SUN computer workstation and a Windows-like operating system.  To learn more about XPS, look up XPS or ESCA (Electron Spectroscopy for Chemical Analysis) on Kratos’ web site at www.Kratos.com.

Scanning Electron Microscopy

The Amray 3300FE field emission SEM with PGT Imix-PC microanalysis system provides three-dimensional visual interpretation and elemental analysis of a specimen surface.  The electron optics allow a depth of focus nearly 300X that of the light microscope, as well as a magnification range from 15X to 100kX at accelerating voltages from 1-25kV.  The SEM resolution at 25kV is 1.5 nm.  The 2048x2048 frame buffer allows high resolution (4.8 MB .tif) micrographs to be saved on the SEM computer and/or transferred directly to your office computer via ethernet or CD.  Imaging modes available are:  full field, split screen, dual magnification, variable partial field, spot, and elemental mapping.

Transmission Electron Microscopy

Two transmission electron microscopes are available in the Electron Microscopy Facility (Kendall Hall).  The JEOL 100S TEM is a teaching microscope with accelerating voltages from 40 to 100kV and has magnification from 1000X to 100kX with resolution capabilities of 1.5 nm. The electronic alignment and automatic vacuum-valving systems make this microscope easy to operate.  The camera holds 50 sheets of film, and micrographs are printed with magnifications and sequential numbers.

The Zeiss/LEO 922 Omega TEM is a research microscope with accelerating voltages of 120 and 200kV and has magnification from 80X to 1,000,000X with a resolution line of 0.12nm.  The in-column energy filter allows researchers to look at unstained or faintly stained materials and tissues.  The high resolution objective lens allows the user to tilt a single-grid specimen holder plus or minus 15 degrees.  The camera holds 40 sheets of film; and micrographs are printed with magnification, label, micron bar and sequential numbers.  

Confocal Microscopy