product review
Raman on the Run A portable analytical tool puts the power of photonics in the hands of almost anyone. Cheryl M. Harris
S
am Bryan and his co-workers at Pacific Northwest National Laboratory (PNNL) have a job to do that, at first, just sounds like another day at the office: They’ve been assigned to analyze some chemical compounds for the U.S. Department of Energy. But these compounds are radioactive waste stored underground in 177-million-gallon tanks since World War II. The history researchers want to repeat—this time the right way—is the disposal of the radioactive waste at the 560-square-mile Hanford Site in southeastern Washington state. The waste is mostly precipitated sodium nitrate, sodium nitrite, sodium phosphate, and sodium sulfate. “It’s all from the processing of the uranium fuel that scientists produced plutonium with . . . for the weapons program,” explains Bryan. And the solution isn’t leaving the waste in those tanks, he adds. “The issue is: These tanks are aging.” For the researchers, Raman spectroscopy came to the rescue. To remove these radioactive salts, scientists had to dissolve them and send them down stainless steel pipes at a rate of ~5 gal/min to other tanks for processing and vitrification. During this waste removal project, PNNL researchers needed to know how much salt they were processing and whether they were efficiently dissolving the salts being pumped from tank to tank. Meanwhile, says Bryan, project engineers wanted to make sure
the analyses wouldn’t slow things down. They sought a fast, automated device rugged enough to withstand radiation. After looking at various analytical techniques ranging from fluorescence to NMR, Bryan’s group chose a transportable Raman system to help them do the job, which is an ongoing project. “Our task was to come up with a good process monitor that could inline measure the analyte concentration on the fly as it’s going down the pipe,” he says. “Raman came to the very top [of the list] because it was anion-specific, and it was very easy to implement that in a radioactive environment. The spectrometer was not down in the pit. We could actually get the light down there by fiberoptic cabling.” Having a doctorate is no longer required to operate a Raman device, say experts. Today, these systems can be downscaled for easy use and moved out of the laboratory for everyday industrial or forensic applications. Last year, Analytical Chemistry explored mostly benchtop Raman systems—how they’ve come
down in price and are now easier to use (1). This Product Review shows how large benchtop Raman units have been shrunk down to marketable portable analyzers that can run on batteries or a car’s cigarette lighter. Table 1 lists some examples of portable Raman systems available to prospective buyers.
The power of portable Raman Whether they’re for the technician employed at a food-processing plant, a federal worker at the Occupational Safety and Health Administration, or an agent at the U.S. Federal Bureau of Investi-
F E B R U A R Y 1 , 2 0 0 3 / A N A LY T I C A L C H E M I S T R Y
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product review
Table 1. Selected portable Raman spectrometers and microscopes. Product
Handheld Portable Raman Spectrometer (RSL-1)
InPhotote
Scout
Company
Digilab U.S.A 68 Mazzeo Dr. Randolph, MA 02368 781-794-6400 www.digilabglobal.com or www.ramansystems.com
InPhotonics, Inc. 111 Downey St. Norwood, MA 02062 781-440-0202 www.inphotonics.com
Spectracode Purdue Research Park Business & Technology Center 1291 Cumberland Ave., Ste. B West Lafayette, IN 47906 765-463-7427 www.spectracode.com
Price (U.S.D.)
~$25,000+
≤$50,000
~$55,000
Size h w d (cm)
15.24 30.48 10.16
23 41 25
18 53 32 (attaché case)
