Oliver PreslyHow does the Resolve handheld Raman analyzer work?
The Resolve system is a Raman spectrometer and uses Raman spectroscopy—a well stablished spectroscopic technique—for chemical identification of a wide variety of substances.
Typically, the Raman technique uses a monochromatic light source, such as a laser, to illuminate a sample. A small proportion of the light that is scattered from the sample changes in energy, based on specific energy levels in the molecule. This is collected and separated by a spectrograph. The resulting spectrum can be matched to a known library spectrum to provide identification of a single chemical or a mixture. Resolve is unique as it uses a Raman variant, spatially offset Raman spectroscopy (SORS), to conduct Raman measurements through colored and opaque materials—meaning it can identify what is inside a wide variety of sealed containers.
Learn about the fundamentals of Raman spectroscopy and how Raman spectrometers work:
- What is Raman Spectroscopy? – A comprehensive FAQ guide to all things Raman
Is the Agilent Resolve just another Raman spectrometer?
The Resolve Raman system is the world’s only handheld Raman system that enables true through-barrier identification of hazardous or contraband materials. Unique to Agilent, our proprietary handheld spatially offset Raman spectroscopy (SORS) technology enables positive identification through a wide range of sealed nonmetallic containers, barriers, and packaging, eliminating the need to open the container.
SORS works through many millimeters of material, enabling accurate chemical analysis through barriers such as paper, glass, plastic, fabric, and even skin. The method requires no previous knowledge of the container or surface material and does not require direct physical contact.
Find more information on SORS and its applications:
How does Raman compare to FTIR?
Both Raman and FTIR are spectrally detailed techniques containing functional group and so-called fingerprint regions. The vast majority of chemicals are both Raman and mid-infrared (MIR) active and their spectral signatures are both complementary and supplemental. FTIR and Raman peaks/bands are both derived from symmetry rules—whilst FTIR requires a degree of dipole moment for a peak to be active, Raman spectroscopy relies on polarizability. These two qualities are not mutually exclusive, and the two techniques work very well together. For example, the complexity and variety of narcotics and hazardous chemicals often benefit from a dual identification approach, where the parallel Raman and FTIR data enables a positive identification which would be difficult with any single technique.
For more information:
- Combined spectroscopy techniques for narcotic identification - 2022 - Wiley Analytical Science
- What Is FTIR Spectroscopy? – A comprehensive FAQ guide to all things FTIR
The most popular technique for FTIR by far uses a diamond ATR (attenuated total reflectance) interface, which requires that a sample or an aliquot of powder be transferred atop a crystal and then a clamp provides considerable force to ensure contact with the crystal. Raman spectrometers can be used for most samples through clear bags or simple clear containers, without the need for sample removal. Resolve’s through-barrier SORS capability expands the range of containers where sampling is not needed to many opaque and colored containers.
Overall, the main points when comparing Raman to FTIR for hazardous material detection are:
- Raman is non-destructive - samples do not need to be crushed or ground.
- Raman is non-invasive - samples do not need to be removed from a container or decanted in most cases. SORS increases this capability.
- Raman is insensitive to water in aqueous systems.
- The spectral detail is equally as high for both techniques.
What can the Resolve handheld Raman analyzer identify?
Raman has a wide variety of applications as it can be used to analyze many different samples. In general, it is suitable for analysis of:
- Pure chemicals, mixtures, and solutions
- Solids, powders, liquids, gels, slurries, and gases
- Inorganic, organic, and some biological materials
Typical examples where Raman is used today for field detection include:
- Explosives
- Drugs of abuse
- Pharmaceutical drugs
- Toxic industrial chemicals (TICs) and toxic industrial materials (TIMs)
- Common chemicals
- Food samples
- Geological samples
- Academic research in the field or a lab
Learn more:
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