Analytical Chemistry and Microscopy Laboratory

To furnish high-quality analytical support and technical consultation to research units of the Forest Products Laboratory, Forest Service and outside organizations to further Forest Service goals.

Analytical Chemistry and Microscopy Laboratory, with its highly specialized team of chemists and equipment, provide high-quality analytical support and technical consultation to researchers within the U.S Government and private sectors with focus in the following areas:

• Elemental analysis
• Spectroscopy
  • Infrared
  • Nuclear Magnetic Resonance
  • UltraViolet / visible
  • X-Ray Photoelectron
• Chromatography
  • Gas Chromatography/Mass spectrometry
  • Liquid Chromatography/Mass spectrometry
  • Sugar analysis
• Microscopy
• Atomic Force Microscopy
• Nanoindentation
• Scanning Electron Microscopy
• Transmission Electron Microscopy

Chromatography

Gas Chromatography/Mass Spectrometry

GC/MS is used for the separation and chemical identification of components of mixtures of volatile materials. The components are separated using gas chromatography and the individual components identified through mass spectroscopy.

• Gas phase separation
• Volatile materials
• Sensitive and specific detection

High Pressure Liquid Chromatography

Ion chromatography is mostly applied for quantitative sugar analysis--the resolution and quantification of polysaccharides after hydrolysis. Capability also exists to separate polymeric species by molecular weight using gel permeation chromatography.

Sugar Analysis

All carbohydrates (cellulose and hemicellulose) are composed of sugar molecules which are chemically linked. Through sugar analysis the carbo-hydrates are decomposed into individual sugars. The mixture of sugars is separated by chromatography and each sugar is measured quantitatively.

• Hydrolysis (carbohydrate -> sugars)
• Chromatographic separation
• Electrochemical detection
• Quantitative
• Sensitivity and limits vary
• Difficult to look for small differences

Liquid Chromatography/Mass Spectrometry

Similar to GC/MS but is not limited to materials which can be volatilized. Separation of mixtures is effected by chromatography of solutions. The solutes are separated from the solvent at the entrance of the mass spectrometer.

• Separation from solution
• Very sensitive and specific detection
• Fragment to ions then weigh
• Difficult transfer solute to gas phase

Microscopy

Scanning Electron Microscopy (SEM/EDX)

SEM provides image resolution exceeding that obtained by optical microscopy. The current microscope can image samples in low vacuum and without the application of metal coatings. It is also equipped with an energy dispersive x-ray analyzer which can be used for image-wise elemental analysis. Our SEM is also capable of imaging natural materials without extensive drying, so that they can be observed in a native state. The laboratory also has optical microscopes for polarized light, phase contrast or fluorescence microscopy.

Transmission Electron Microscopy

Transmission electron microscopy (TEM) offers the possibility of sub-nanometer spatial resolution along with limited image-wise chemical information. The most serious limitations are that specimens must be thin enough that only single electron scattering events are likely--ca. 100 nm or less--and specimens must resist electronic damage.

Nanoindenter

The nanoindenter uses a fine stylus to measure hardness and stiffness of materials at a sub-micrometer scale. The stylus can also be used to create topographical images. These measurements of mechanical properties at a microscopical scale support the development of hardened wood products, more durable adhesives and better composites. In addition it is being used to explore the structure of wood cell walls which is still not completely understood.

Atomic Force Microscope (AFM)

This is an extraordinarily versatile tool for 3-dimensional imaging at a resolution which cannot be achieved by light microscopy. Sample preparation for AFM is often easier than for electron microscopy.

Hysitron Triboindenter

Atomic Force Microscope, Optical Microscope and Nanoindenter in one.