Page 9 - Prescription for Crime Drug Testing

Pre-Lab

Solutions

1. Why must forensic technicians perform a 4. Why is it important to identify the exact drug
confirmatory test after receiving a positive and the quantity?
result on a pre sumptive test? In most jurisdictions an individual is punished
False positives frequently occur, therefore a based on both the type of drug and the quantity
confirmatory test is required in order to identify that they possess.
the substance.

5. Describe the function of a GC-MS.
2. What is a false positive? The gas chromatograph takes the chemical
A false positive test result means that the test compound and reduces its chemical structure
you have run has returned positive for the to molecules. The difference in the chemical
suspected substance, but, in reality, it is another properties of each different molecule will
substance completely. separate the molecules as the substance
travels the length of the column. The molecules
take different amounts of time to exit the
3. What is a drug that can usually be identified gas chromatograph, which enables the mass
just on the visual appearance of the spectrometer to capture. and detect the
substance? molecules separately. After the GC produces
Marijuana or intact prescription pills can often these fragments of the substance, the MS
be identified just by visual appearance. is used to classify the chemical fragments
and create a ratio with its mass and electrical
charge, called the mass-to-charge ratio.

THE MYSTERY OF LYLE AND LOUISE 9