Page 16 - Prescription for Crime Drug Testing
P. 16
Each unknown substance is made of many different Ultraviolet Spectrophotometry is a confirmatory test
molecules that, when combined create, a separate similar to the GC-MS. In this analysis the unknown
chemical compound (i.e. cocaine, LSD, HTC, substance is identified through detection of the
etc.). A drug technician inserts a minute amount light being reflected by the main elements of the
of the unknown substance into the GC-MS. The compound. This is analyzed and compared to a known
gas chromatograph then takes this chemical sample range that helps identify the unknown drug.
compound and reduces its chemical structure to
individual molecules. The difference in the chemical Many real-life examples show the importance of
properties of each molecule will separate the forensic testing and how it can be used to clarify
molecules as they travel the length of the column. questionable cases. In 1984, FedEx employees
The molecules take different amounts of time to examined a damaged package of a cardboard box
exit the gas chromatograph, which enables the wrapped in brown paper. Inside they found a tube
mass spectrometer to capture and detect the that had a number of plastic bags placed inside one
molecules individually. After the GC produces these another. In the innermost bag they found a white
fragments, the MS is used to classify the chemical powder substance, and they subsequently called
compounds and create a ratio with its mass and the Drug Enforcement Administration (DEA) to
electrical charge, called the mass-to-charge ratio. investigate. When an officer arrived, he removed
With this information about the unknown chemical a small trace of the powder and performed a
substance, a forensic scientist is able to identify presumptive field test which indicated the presence
the chemical fragments and place them back in the of cocaine. A search warrant was issued for the
proper order, thus restoring the whole chemical address to which the package was to be delivered,
compound using their expertise and knowledge of and the recipients were arrested and eventually
general and organic chemistry. convicted of drug possession.
16 THE MYSTERY OF LYLE AND LOUISE
