Raman spectroscopy is a highly efficient technique used to identify chemicals.
While the Raman Effect has been known for almost 100 years, recent developments have enabled Raman spectrometers to be packaged into compact, field portable instruments suitable for use by police, emergency services crews, border security/customs, the military, and first responders.
Furthermore, their simplistic operation and ability to provide chemical analyses in seconds make them ideally suited to various practical applications such as identifying drugs, explosives, chemical warfare agents, hazardous materials, and routine quality control.
Image Credit: Rigaku Corporation
Handheld Raman spectrometers allow non-destructive analysis and can scan through packaging, streamlining the inspection process and protecting operators from the risk of exposure.
The specificity of Raman comes from it being a vibrational spectroscopy technique. Any chemical or physical changes that result from molecular vibrations will change the Raman spectrum making it highly sensitive to chemical and some physical differences in materials.
How Does Raman Spectroscopy Work?
Raman spectroscopy is an established vibrational technique that works by first exciting a sample with a laser. A small portion of this light undergoes “inelastic scatter” (also referred to as the Raman scatter or the Raman Effect). A detector then receives and reads the return signal, resulting in what is referred to as a Raman spectrum.
The Raman spectrum contains a series of peaks related to features in the sample’s molecular structure. Each compound’s Raman spectrum is unique and serves as a “chemical fingerprint” that can be used to identify an unknown compound or a mixture of compounds. Click here for more information on how Raman Spectroscopy works.
Image Credit: Rigaku Corporation
Why 1064 nm Raman Spectrocopy?
The most common excitation wavelength used in handheld Raman spectrometers is 785 nm. However, to identify unknown substances, 1064 nm is more effective since it reduces absorption by the sample, allowing more signals to be reflected. This is known as fluorescence interference, and it results in stronger signals and faster analysis times.
Reduced fluorescence allows 1064 nm handheld Raman to:
- Identify colored, dirty, or impure samples
- Scan through colored wrappings, packaging, or containers
- Analyze mixtures without additional operator action
- Generate results in less than one minute
Example of 785 nm spectra (in red) and 1064 nm spectra (in blue) of a chemical through an amber bottle. Image Credit: Rigaku Corporation
Key Design Features of a Handheld Raman Spectrometer
Ensuring that an analytical technique's hardware and software design is fit for purpose is essential when it is put to use in the field.
Rigaku Analytical Devices is the pioneer in handheld 1064 nm Ramen technology and now has thousands of units deployed for in-field use. Based on its award-winning platform (R&D 100 Award in 2015), Rigaku handheld Raman analyzers are the optimal high-quality 1064 nm excitation handheld Raman spectrometers.
They are small, lightweight, rugged, versatile, and easy to use without compromising spectral quality. Each module and major functional component of the Rigaku ResQ CQL and Rigaku Progeny have been designed and built to meet these requirements.
Hardware Design
Handheld Raman devices, such as those manufactured by Rigaku, are designed to be used by field operators in high-stress environments. Therefore, they feature compact, rugged designs for easy transportation and field use (including purpose-designed travel cases).
The Rigaku portfolio of handheld Raman analyzers is certified to MIL-STD-810G – a U.S. Department of Defense test method standard, and the analyzers have an IP-68-rated enclosure, protecting them against dust and dirt.
Image Credit: Rigaku Corporation
GUI -Graphical User Interface
Rigaku analyzers also benefit from an intuitive touchscreen interface that requires minimal training to use. The interface features a large icon-driven menu that can be operated by a user wearing full PPE.
Image Credit: Rigaku Corporation
Library Components/Chemical Recipes
The ResQ CQL features an onboard library of over 12,000 chemical substances for identifying unknown substances. The user can add to or update this library at any time.
4C Technology is standard on the ResQ CQL. This feature expands incident response by warning users of potential dangerous combinations while scanning individual chemicals.
For quality control applications, the Progeny can also be used for rapid screening in pass/fail mode, with operators able to set suitable thresholds to define levels of acceptability.
Image Credit: Rigaku Corporation
Onboard Camera
The Rigaku analyzers' onboard camera can capture pictorial evidence that can be used for traceability in reporting or as a barcode scanner for error-free sample information entry.
Image Credit: Rigaku Corporation
The Ability to Scan Through Packaging
The nose cone of Rigaku analyzers is adjustable, allowing it to scan through different thicknesses and types of packaging.
Identification of Low Concentration Levels
The optional QuickDetect feature of the ResQ CQL allows non-visible quantities of a substance to be detected.
Applications of Handheld Raman Devices
Handheld Raman spectrometers are being used more frequently as knowledge of their applications and versatility grows. Further examples of their current uses are listed below.
Chemical Threat Analysis
Customs, police, the military, and other emergency and first responders are often required to deal with chemicals of unknown nature and origins, such as explosives, chemical warfare agents, toxic industrial materials, or household hazardous materials.
Handheld Raman provides a fast and effective method to identify unknown substances, even through their packaging.
The U.S. Department of Defense has committed to modernizing its DR SKO (Dismounted Reconnaissance Sets, Kits, and Outfits) systems worldwide using Rigaku ResQ CQL 1064 nm handheld Raman spectrometers to be able to better respond to potential chemical threats. Click here to read the full story.
Image Credit: Rigaku Corporation
Illicit Drug and Counterfeit Screening
Many illicit drugs are manufactured in backyard laboratories with little or no quality control. The supply of these substances offers yet another avenue for substitution or contamination using potentially toxic cutting agents.
Handheld Raman provides a crucial role in drug screening and is a proven technique to easily discern legitimate pharmaceuticals from illicit or counterfeit drugs, such as the current use of fentanyl by cartels.
Image Credit: Rigaku Corporation
Handheld Raman can also be used to detect precursor chemicals; for example, Rigaku ResQ handheld Raman was used by Thai authorities to identify crystal meth bound for Taiwan, hidden in a powdered form. Thai customs officials were thus able to intercept nearly 900 kg of crystal methamphetamine worth $88 million dollars.
Precursor Chemicals
Precursor chemicals are used in the illegal manufacturing of illicit drugs or explosives. These chemicals can be obtained legally and are monitored when purchased in large quantities.
However, they are often disguised among criminal trafficking groups. Handheld Raman is an ideal application for verifying shipments during the transportation process.
Click here to read the case study describing how the Rigaku ResQ CQL was used to degrade the illicit precursor supply chain in Myanmar.
Image Credit: Rigaku Corporation
Hazardous Household Chemicals
Common materials found in homes and businesses can create hazardous waste if not disposed of properly, especially when their containers break or leak.
First responders need to identify these potentially hazardous materials immediately to mitigate the potential threat to others correctly. Raman technology provides responders with a molecular fingerprint of substances and material identification.
Raman spectroscopy is a non-destructive, non-contact method that can analyze substances through glass, plastic bags, and bottles, protecting the user from potentially hazardous exposure.
Homemade Explosives
As commercial explosives become more difficult to obtain, terrorists turn to the production of homemade explosives (HMEs). HMEs are typically produced in makeshift laboratories using materials easily obtained by the public.
They are synthesized under improvised conditions, typically resulting in a product that contains impurities, many of which color the sample and produce fluorescence. This makes them difficult to analyze with traditional 785 nm-based Raman systems.
Image Credit: Rigaku Corporation
Chemical Warfare Agents
History shows that chemical warfare agents (CWAs) are the most widely proliferated and used weapons of mass destruction (WMDs). Unlike ultrapure laboratory-grade chemicals, munitions-grade CWAs used in attacks are likely to contain impurities from the storage container, degradation, or unreacted precursors.
These impurities often cause fluorescence when analyzed using 785 nm-based Raman analyzers. To minimize fluorescence in these real-world threats, the Rigaku portfolio of handheld Raman analyzers uses a longer wavelength laser at 1064 nm, which leads to more reliable identifications and shorter measurement times.
Image Credit: Rigaku Corporation
Click here to read how Rigaku 1064 nm Raman is used in conflict regions.
Quality Assurance/Control in Pharmaceutical Manufacturing
Pharmaceutical manufacturing is a precise science. The exact chemical composition of the final product will directly impact its efficacy.
This chemical composition often directly correlates to the purity of materials, which can easily be checked and monitored using handheld Raman devices. Handheld Raman can also be used to quickly check the composition of the final products.
Image Credit: Rigaku Corporation
The success of manufacturing operations relies on processes operating within specified limits. When these operations require raw materials, the Rigaku Progeny handheld Raman can provide a convenient way to confirm their chemical makeup.
Understanding the chemical analysis of raw materials means that they can be rejected before reaching the workflow if they do not meet certain specifications, for example, if they have been mislabeled.
This can prevent the issues and considerable expenses incurred if a problem with the raw material is not identified until the Q.C. of the final product. Small variations in the chemical composition of the raw materials can also be compensated for if detected early.
Click here to read how pharmaceutical manufacturers use handheld Raman.
Products
Source: Rigaku Corporation
| Rigaku Model |
ResQ CQL |
Progeny |
| |
 |
 |
| Applications |
Unknown chemical identification |
Raw material identification |
| Industries Served |
Customs, military, first responders, law enforcement, harm reduction |
Pharmaceutical, cosmetics, nutraceutical manufacturing, and academia |
| Excitation Wavelength |
1064 nm |
| GUI Interface |
Touchscreen or button |
| Onboard camera |
Included |
| Standard Library |
>12,000 compounds |
| User-Created Library |
Included |
| File Export for Reporting |
Included |
| Sampling Accessories |
Available |
Available |
| 4C Technology for recipe monitoring and alerts |
Included |
Not applicable |
| QuickDetect Automated Colorimetrics |
Optional |
Not applicable |
| Ruggedness |
U.S. MIL-STD 810 G, IP-68 |
| Warranty |
24 months |
| Learn More |
|
Progeny |
This information has been sourced, reviewed and adapted from materials provided by Rigaku Corporation.
For more information on this source, please visit Rigaku Corporation.