Portable Raman Spectroscopy as a Functional Tool in Homeland SecurityIzake, E. , Forensic and homeland security applications of modern portable Raman spectroscopy. Forensic Science International. (2010), vol 9, pp. 1 – 8

Kassandra Luening and Neil Rybak

Conventional Techniques

GC/MS HPLC/MS THZ (Terahertz radiation spectroscopy)

Limitations Operator must come into contact with potentially

hazardous samples Instruments must be disposed of or decontaminated after

contact with hazardous materials These techniques are not portable. Require the

movement of complex instruments

Portable Raman Instruments

Allows for the portability of Raman spectroscopy

High volumes of samples can be scanned, without the operator coming into contact with the sample, and the units are now fully portable

Chemistry of Raman Spectroscopy

Monochromatic light applied to sample Incident light is scattered

Rayleigh (elastic) and Raman (inelastic) Rayleigh scatter is filtered out The returned scattered light is a

different wavelength This difference corresponds to an

energy shift which provides a unique chemical fingerprint

Advantages of Raman Spectroscopy

Provides molecular fingerprints of each analyte, providing the possibility of highly selective determinations

Applicable to any optically accessible sample; organic, inorganic, or biological

Solid, liquid, gaseous, transparent and non-transparent samples can be measured

Aqueous solutions present no special technical problems

Sample scanning is non-invasive

Detection can be of sample sizes from 1 µm – dm2 and distances from millimetres up to several metres

Raman fingerprint is independent of excitation wavelength, allowing for the use of any laser for excitation

Detection can be done day and night without the presence of background signals due to ambient light interference

Raman spectroscopy has become fully portable

Examples of Portable Raman in Use

Has been used to identify illicit drugs using NIR laser excitation2

Capable of rapid detection, acquisition times of 1 minutes when analyzing amphetamine street samples3

Ultra trace amounts of illicit drugs (5 – 20 µm in size) found under nail varnish in a non-destructive manner in under three minutes4

Stand-off Raman detection of hazardous substances Constructing a gated

detector system can restrict the laser pulse of the light source

Data collected at the time the laser is expected to arrival at the sample

Allows for sample detection from distances up to 100 metres5

Ahura First Defender

Currently in use by emergency response teams6

Has been used to assist the FBI to identify hazardous materials7

Results of the analysis of the “First Defender” instrument have been used in court to assist in a conviction9

Ahura TruNarc

The ease of use of the instrument and the library of samples “potentially eliminates the need for a chemist to testify” Simple non-expert use of the instrument

Rigaku Firstguard Handeld Analyzer8

No sample prep needed

Operated like a point and shoot camera

Delivers results in seconds with no chance of human error

User can either build their own database or use supplied library

Conclusions Portable Raman has been shown to be more

effective than conventional methods in the detection of drugs and other hazardous samples No contact of sample with analyst or

instrument High throughput capability Can be used in close proximity of sample or at

distances Can analyze organic, inorganic and biological

samples through containers, in both light and dark environments

New portable instrumentation is user friendly allowing non expert users to easily identify samples

References1. Izake, E. , Forensic and homeland security applications of modern portable

Raman spectroscopy. Forensic Science International. (2010), vol 9, pp. 1 – 8

2. S.E.J. Bell, D.T. Burns, A.C. Dennnis, L.J. Matchett, J.S. Speers, Composition and profiling of seized ecstasy tablets by Raman spectroscopy, Analyst 125 (10) (2000) 541 – 544

3. E. Katainen, M. Elomaa, M. Laakkonen, E. Sippola, P. Niemela, K. Janne Suhonen, Jarvinen, Quantification of the amphetamine content in seized street samples by Raman Spectroscopy, J. Forensic Sci. 52 (1) (2007) 88 – 90

4. E. Ali, H. Edwards, M. Hargreaves, I. Scowen, Raman spectroscopic investigation of cocaine hydrochloride on human nail in a forensic context, Anal. Bioanal. Chem. 390 (4) (2008) 1159 – 1166

5. S.K. Sharma, New trends in telescopic remote Raman spectroscopic instrumentation, Spectrochim. Acta Part A 68 (5) (2007) 1008 – 1022

6. City of Albany, NY. Department of Fire, Emergency Services and Code Enforcement Accomplishments for 2009.

7. Monmouth County Health Department Hazardous Materials Response/UST Units 2009 Annual Report

8. Information obtained from brochure provided by contact with Rigaku Raman Technologies (www.rigakuraman.com)

9. Rains, S. (2011, May 7), Convict Guilty of Courthouse Hoax. Lawton Constitution (http://www.swoknews.com/main.asp?SectionID=11&SubSectionID=98&ArticleID=34618)

Ahura TruScan in use