Forensic Analysis of an Artificial Sweetener Commonly Employed in Hoax Powder Attacks using Morphologically Directed Raman Spectroscopy
Application Note Feb 27, 2015
Malvern Instruments Limited
In the wake of the September 11th terrorist attacks, there was an influx of white powder events throughout the United States. A white powder event is when an unknown white powder is received in the post. More often than not, the attacks do not contain any toxic materials and are carried out for the sole purpose of causing terror and damaging infrastructure. Since these attacks, the FBI and US Postal Service have responded to thousands of white powder events.
This application note details how Morphologically Directed Raman Spectroscopy (MDRS) using the Morphologi G3-ID can be applied to the forensic identification of commercially sourced white powders commonly used in hoax powder attacks.
Artificial sweeteners are one of the most commonly employed commercial sources of white powders. These blends are simple mixtures of a sweetening agent and bulking material. Since, the sweetening agents used are several times sweeter than a comparable amount of table sugar, a bulking agent or filler, such as dextrose, is required. Detection of the sweetening agent allows identification of the brand of sweetener.
Raman spectroscopy is a useful technique in forensic science for determining molecular chemistry because it is rapid, reliable, does not require contact with the sample, and is non-destructive. The technique can be used to verify that hoax powders are artificial sweeteners. However, when doing a traditional bulk analysis, the high volume of bulking material present has a tendency to drown out the Raman signature of the sweetening agent. Raman microspectroscopy has the advantages of bulk Raman spectroscopy but can also be used to analyze and identify the various chemically distinct components of the white powder.
Information from particle morphology and size is also valuable for differentiating artificial sweeteners that are mixtures of the same components. Automatic image analysis takes the subjective element out of the measurement of particle size and morphology. It also makes the process more rapid than counting and measuring the individual particles within a greater mixture.
When Raman microspectroscopy is paired with automatic image analysis of the particles, as in Morphologically Directed Raman Spectroscopy (MDRS), physical and chemical information about the components of the mixture can be obtained. This can be used for discrimination and brand identification between mixtures, thus making it an ideal tool for the investigation of suspicious white powders.