One of the newest trends in spectrometers utilizing near infrared, infrared, or Raman spectroscopy is to make measurements in process, manufacturing, and field situations using portable instruments. These instruments are specifically designed for use in field and manufacturing plant deployment. Applications for such devices include inspection and security, forensics, safety and quality, pharmaceuticals, food, beverages, and agriculture; environmental analysis, authentication, and medicine. This presentation will describe key applications currently in use as well as the theory of and instrumentation for process and field spectrometer deployment.

The different spectroscopic techniques covered include near infrared, infrared, and Raman with comparisons of the advantages and disadvantages of each technique and how to optimize each for specific applications. Handouts include charts for selection of sources, detectors, beamsplitters and other spectrometer components, as well as optimization of sample presentation techniques for both quantitative and qualitative analysis.

Spectra-structure correlation charts are also made available as handouts for comparison of band positions and optimization of spectral band selection for specific applications of each of the techniques.

A brief description is given below for the main uses of near infrared, infrared, and Raman spectroscopic techniques - these will be covered in greater detail during the presentation:

Near infrared spectroscopy is used where multicomponent molecular vibrational analysis is required in the presence of interfering substances. The near infrared spectra consist of overtones and combination bands of the fundamental molecular absorptions found in the mid infrared region. Near infrared spectra consist of generally overlapping vibrational bands that are non specific and poorly resolved without specialized math pretreatment. The use of chemometric mathematical data processing can be used to calibrate for qualitative or quantitative analysis despite these apparent spectroscopic limitations. The dominant near-infrared spectral features include the methyl C-H stretching vibrations, methylene C-H stretching vibrations, aromatic C-H stretching vibrations, O-H stretching vibrations, methoxy C-H stretching, and carbonyl associated C-H stretching. In addition, N-H stretching from primary amides, secondary amides (both alkyl, and aryl group associations), N-H from primary, secondary, and tertiary amines, and N-H from amine salts predominate near infrared spectral features of polymers and organic compounds. Bending modes and combination bands are also prevalent such that C-H stretching occurs in eight distinct spectral windows from 690 nm (nanometers) to 2950 nm.

Mid infrared spectroscopy provides a measurement technique for intense, isolated and reliable absorption bands of fundamental molecular vibrations from organic and inorganic compounds and composite materials. The spectrometric methodology allows for univariate calibration with higher signal strength (absorptivities) required for solid, slurry, liquids or gas phase measurements. Relatively small pathlengths of 0.1 to 1.0 mm are required for hydrocarbon liquids and solids. The technique is generally incompatible with the use of fiber optics, but specialized fiber materials exist that allow such measurements. Instrumentation is higher cost than near infrared spectrophotometers for the most part. Dominant mid-infrared spectral include the C-H (methyl, methylene, aromatic, methoxy, and carbonyl) fundamental stretching and bending molecular vibrations, O-H (hydroxyl) stretch fundamental vibrations; N-H (amine) stretching, C-F (fluorocarbon) stretching, -C=N (nitrile) stretching, -C=O (carbonyl) stretch from esters, acetates, and amides; C-Cl  stretch from chlorinated hydrocarbons, and -NO₂ from nitro- containing compounds. The fundamental regions and fingerprint regions are used for interpretation of key structural characteristics and identification.

Raman spectroscopy can be used for a variety of measurements on samples that are aqueous in nature, are difficult to sample, or where glass sample holders are present. Carbon dioxide, water, and glass (silica) are weak Raman scatterers and thus there is generally minimal interference problems when analyzing samples having these properties. There is typically no sample preparation involved in samples measured using Raman. Raman spectroscopy is complimentary to mid infrared spectroscopy in the measurement of fundamental molecular vibrations. Raman measurements are compatible with fiber optics. Raman measurements exhibit high signal-to-noise and a reasonable cost for instrumentation. The dominant Raman spectral features are acetylenic C=C stretching, olefinic C=C stretching at 1680-1630 cm^-1; N=N (azo-) stretching, S-H (thio-) stretching, C=S stretching, C-S stretching, and S-S stretching bands.  Raman spectra also contain such molecular vibrational information as CH₂ twist and wagging, carbonyl C=O stretch associated with esters, acetates, and amides; C-Cl (halogenated hydrocarbons) stretching, and -NO₂ (nitro-/nitrite) stretching. In addition, Raman yields information content of phenyl-containing compounds at 1000 cm^-1.

This audio seminar CD is presented by Jerry Workman, a worldwide expert on spectroscopy.

A detailed outline and Dr. Workman's qualifications follow below.

All Participants will receive:

Process & Field Applications using Portable Instruments
for Near Infrared, Infrared, and Raman Spectroscopy

Part I
A worldview of portable and process instruments, their uses, and a survey of available technologies and commercial instruments

• Background of portable instruments
• Survey of available technologies

Part II
Principles of Spectral Measurements: A comparison of the various techniques

• Molecular vibrations
• Absorption spectroscopy
• Quantitative analysis
• A comparison of NIR, IR, and Raman spectra

Part III
Spectra-Structure Correlation and Assignments: How to locate specific chemical groups

• Details of Near Infrared Spectra
• Near Infrared Spectra-Structure correlation charts (handouts)
• Infrared Spectra-Structure correlation charts (handouts)
• Raman Spectra-Structure correlation charts (handouts)

Part IV
How to select the appropriate spectroscopic technique for different measurement and sampling situations

• The Electromagnetic Spectrum (nomenclature) - consider your application
• Qualitative analysis applications: Choosing the right spectrometer tools (handout)
• Quantitative analysis applications: Choosing the right spectrometer tools (handout)
• Sampling techniques and methods: Transmission, reflection, ATR, DRIFTS, Specular, Raman

Part V
Spectroscopic Techniques and Technologies

• FT instruments
• Selection of optical components (Comparison chart)
• The Michelson Interferometer, FT-IR, FT-NIR, and FFT
• Raman spectroscopy
• Comparing NIR, IR, and Raman instruments

Part VI
Spectroscopic applications for each technique

• Inspection and Security
• Forensics
• Safety and Quality
• Medicine and Pharmaceuticals
• Food and Beverages
• Agriculture
• Environmental
• Authentication
• NIR Materials applications
• Other applications

Part VII
References

• Spectra-Structure references for NIR, IR, and Raman
• Process/Field spectroscopy - Textbooks
• Process/Field spectroscopy - Journals

Jerry Workman

Jerome (Jerry) J. Workman, Jr. is the Director of Research, Technology & Applications Development for Molecular Spectroscopy & Microanalysis at the Thermo Electron Corporation. He was formerly Chief Technical Officer and Vice President of Research & Engineering at Argose Inc., Senior Research Fellow at Kimberly-Clark Corporate Analytical Science & Technology, and Principal Scientist at Perkin-Elmer.

In his career, his focus has been on multiple aspects of spectroscopy, including fluorescence, near infrared, infrared, ultraviolet-visible, Raman, and process spectroscopy as well as chemometrics. He is co-author of the popular Spectroscopy series Statistics in Spectroscopy and Chemometrics in Spectroscopy which have published over 100 columns since 1986. He has authored multiple books, several hundred scientific papers, commercial software programs, and U.S. and international patents. He co-authors the Fundamental Reviews for both Process Analytical Chemistry and Chemometrics for the journal Analytical Chemistry, which includes a wide variety of new process technologies and applications, and serves on the U.S. National Academies NRC Panel for assessment of NIST programs. He was a Charter Member of U.S. Food & Drug Administration PAT and Chemometrics Committee, 2002 and was invited as a Visiting Professor in the Lecture Series at the U.S. Food & Drug Administration, 2002. In 2002 he was the recipient of the Eastern Analytical Symposium Award for Outstanding Achievements in the Field of Near Infrared Spectroscopy, the ASTM International Award of Merit, and IBC International Scientist of the Year.

As former Principal Scientist in the Real-Time Systems Division of Perkin-Elmer he lead software, hardware, and applications work for process NIR (petroleum and fine chemicals), and IR (gas analysis), and light scattering technology for chemical and pharma processes. He was the Perkin-Elmer Industrial Representative for the Center for Process Analytical Chemistry (CPAC) at the University of Washington, and then moved to the Analytical Sciences group at Kimberly-Clark where he was K-C's Industrial Advisory Board representative. At K-C he initiated the use of chemometrics in general analytical and process work and applied process analysis to liquid stream monitoring and high speed web monitoring.  During his time at K-C he chaired the CPAC Industrial Advisory Board, was on the CPAC/University of Washington Policy Board, and the CPAC Industrial Advisory Board Steering Committee. He has also actively participated as a visiting MCEC (Measurement Control and Engineering Center - UT) participant.