A forensics investigator dusts a crime scene for fingerprints. When she finds one, she reaches to her holster, pulls out a handheld device, and aims it at the fingerprint. The device captures the image and also the chemical composition. That chemical analysis reveals that the person who left the print had touched ephedrine—an illegal drug, which is a stimulant that goes by many street names, including meow. With this information, the investigators can use biometrics—the fingerprint— to identify the person and the chemical analysis to start piecing together the crime.
Faster, lighter, and more ergonomic devices emerge
Is this scene a scientific description of reality or a futuristic vision? For now, it’s a look ahead, but not for long. In fact, ongoing research could already make it possible to extract chemicals from the ridges of a fingerprint that has been left behind. In addition, many new devices help forensic scientists take high-powered instrumentation into the field.
At the University of North Texas in Denton, associate professor of chemistry Guido Verbeck works on projects such as this. As he explains, “One side of my research is portable mass spectrometry. We have that down to 12 pounds for the detector and monitor.” That’s a very small device, given that some mass spectrometers take up as much space as some residential dish washing machines. To reduce the size and weight of a mass spectrometry (MS) device, though, something has to go. “When you make a mass spectrometer small, it doesn’t retain all the things that it can usually do.”
That reflects a few trends in field instrumentation for forensics as well as for the field in general. As Verbeck describes it, “The trend is that if you can get the cost and the size down, people will forgive that it doesn’t do everything.”
Motivation to miniaturize
There are many reasons to reduce the size and weight of MS devices. For one thing, says Verbeck, a portable mass spectrometer could improve on the sensitivity—by a couple orders of magnitude—of some existing field tests for drugs. In addition, there’s room in the market for new devices. “If you plot cost versus size in MS,” says Verbeck, “there’s a giant hole at low cost, small size, and the world is moving in that direction.”
Beyond the needs in MS, the ability to make smaller, “fieldworthy” versions of these devices reveals another trend for portable instruments in general. One of the key changes driving advances, says Verbeck, comes from improvements in micromanufacturing. That allows miniature devices to be made in quantity. “We’ve made one-offs for 10 years,” says Verbeck, “but now silicon coating, micromanufacturing, and electrical discharge machining let you make reproducible pieces on the 0.5 to 1 millimeter scale, and that changes everything.” He adds, “Now I can make 20 mass spectrometers, and they all perform the same way.”
Verbeck’s work on developing a fieldworthy device also reveals another trend in this overall area of instrumentation: “If you want a portable instrument,” he says, “something needs to become simpler.”
For a portable MS, this means removing the common front end, which is gas or liquid chromatography. That can require developing new sample preparation techniques for different applications. As an example, Verbeck says, “We came up with a single-solvent method to use MS to see every explosive.” Doing that required modifying the mass spectrometer, but Verbeck did it in a modular way so that it can be tailored for other applications.
In addition to making field devices smaller and lighter, Trey Sieger, market leader, portable analyzers at Thermo Fisher Scientific, which is headquartered in Waltham, Massachusetts, says that there’s a strong trend to make them faster. He adds, “Devices are also built for specific purposes. We see things like a Raman spectrometer that is small enough to fit in a cargo pocket and also much more rugged than a delicate lab instrument.”
The user of such a device—someone on a bomb squad or a soldier, perhaps—might expose the device to extreme temperatures plus other physical assaults. “They need to be able to drop it but still pull out a working device,” Sieger explains.
The growing range of users of field devices drives another trend: usability. As Sieger says, “In general, today’s portable devices need interfaces that allow them to be used by nonscientists.” He adds, “So you’re not just taking a spectrometer to the field and asking it to collect spectral data. It also needs to interpret it, and that requires building some intelligence into the device so people without any scientific background can use it in the field and get useful information.” As an example, he asks, “Is this a drug or an explosive or a pile of sugar that we found on the side of the road?”
Depending on where and how a portable device will be used, it needs different capabilities. If a device will be used to collect data that could be presented in court, for example, the instrument must provide data security so that someone can testify to the validity of the results. The Thermo Scientific TruNarc, for instance, is a handheld Raman spectrometer that identifies narcotics, all without even directly touching the sample, which could contaminate the evidence. “It identifies drugs, cutting agents, [and] precursors,” Sieger says. “There are hundreds of different chemicals that get used in illegal drugs today, especially with all the synthetic drugs, and many look like white powder or some crystal.”
The rampant increase in chemicals used for drugs also demands that a portable device can be upgraded to identify new things. So, Thermo Scientific designed TruNarc to include an updatable library. “In the most recent update,” Sieger says, “the library grew by 70 percent.” He adds, “Customers get free updates for the life of the instrument because they are buying the overall capability to detect raw materials and finished drugs.”
Reaching for more Raman
Other companies also turn Raman spectrometers into handheld devices. For example, B&W Tek in Newark, Delaware, developed the TacticID-GP, and Ocean Optics in Dunedin, Florida, created the IDRaman mini handheld Raman spectrometer.
In describing B&W Tek’s TacticID-GP, marketing communications manager Stephanie Nave says, “It’s geared toward law enforcement and forensic labs, so it includes a library of narcotics, pharmaceutical drugs, precursors, and cutting agents.” She adds, “It’s as easy to use as a smartphone. You scan a sample [and] the device compares the spectra with a library and then provides a match or no match.” Weighing less than two pounds, this device can still detect about 1,000 drugs and narcotics. “Users can also add custom library items and update the system as new drugs or new mixtures come out,” says Nave.
For the IDRaman mini from Ocean Optics, senior applications scientist Yvette Mattley says, “It really is handheld. It fits in the palm of your hand.” She adds, “It can take Raman measurements from solids or liquids in vials. You can also just point and shoot at a surface to make measurements of samples like narcotics or pharmaceuticals anywhere you need to make them.” Ocean Optics provides libraries for matching, and users can also easily add their own spectra for other materials.
This device can even detect trace compounds on a surface because it uses raster orbital scanning. That means that it guides its tightly focused laser beam in an orbital fashion that works its way through a raster pattern, or grid. This increases the sample area interrogated with the tightly focused laser to improve sensitivity while reducing the laser power that lands on any single spot, which means that this device won’t damage even delicate samples or ignite explosive or flammable materials. In addition, this device runs on two AA batteries, which provide 11 hours of operation.
Transforming the techniques
In March 2014, Agilent Technologies, which has its headquarters in Santa Clara, California, delivered a new tool for the field—the 4300 Fourier transform infrared (FTIR) spectrometer. John Seelenbinder, marketing manager for mobile spectroscopy at Agilent, describes this device as a “handheld infrared spectrometer that provides full-frequency range FTIR.” He adds, “It includes lots of the capabilities you’d have on a lab bench model.” In addition to its being smaller and lighter—60 percent lighter—than the previous version, Seelenbinder points out that the 4300 is also more ergonomic.
Although the first portable IR devices were used most by military personnel scanning for hazardous materials, these instruments can also be used to identify illegal drugs and abused prescription drugs. “The idea,” Seelenbinder says, “was to move the technology onto the street so that law enforcement officers can get immediate feedback [and then] police can make actionable decisions.”
That requires fast and accurate results from the 4300. “Improved electronics and better optimization of using the available light allows these capabilities,” says Seelenbinder.
In St. Petersburg, Florida, Field Forensics provides portable materials detection and identification tools based on colorimetric, chromatographic, and spectroscopic technologies. For example, company vice president Michael Kayat describes the microTLC as “a new class of portable, laboratory- quality analysis tool that can be used for a wide range of forensics applications.” This device uses the well-established laboratory technique of thin layer chromatography (TLC). More specifically, says Kayat, “The microTLC is a tool for rapidly separating forensic samples into constituent substances, using a unique combination of accessories and small plates that are pre-spotted with a range of standard compounds.” Consequently, this device compares the separated components in a sample to a “library” of compounds on the TLC plates. The development of new plates expands the range of potential applications.
Forensics scientists, law enforcement officers, first responders, and military professionals can use the high-utility microTLC for many tasks. A few of the applications that Kayat named include identifying multicomponent mixtures of illicit narcotics and controlled drugs and detecting counterfeit medicines and other consumer TECHNOLOGY goods. The microTLC was initially developed together with a major US defense laboratory to identify trace quantities of different types of explosives in complex samples. In addition, says Kayat, “The device can be used in a process that follows US government guidelines for the identification of seized drugs— SWGDRUG—and explosive materials—TWGFEX. The microTLC is classed as a Category B method that can be used for presumptive identification of these substances.”
In less than five minutes, the microTLC provides digital output that, says Kayat, “can be used with a LIMS.” Additional field colorimetric and spectroscopic results on the same samples provide further presumptive and confirmatory results.
In the end, a comprehensive forensics facility requires field and lab instruments. As Sieger says, “No one instrument will replace the huge capability that resides in the lab, but we see the field devices helping a user prioritize what they see out in the field.” That information can be used to decide which samples need further testing at the lab. Sieger says, “It’s more efficient, and it focuses the energy where appropriate.” That’s something that every modern science lab hopes to achieve.