FRSC 2001 – Introduction to Forensic Science Technology
II
Spring, 2014
Homework Assignment #6
(25 points total)
Name
Date
In class today, we talked about various types of chemical instrumentation that are commonly used in the crime
laboratory. Specifically, we looked at the gas chromatograph, the mass spectrometer, the infrared
spectrophotometer, the UV-Vis spectrophotometer, the high performance liquid chromatograph, and the atomic
absorption spectrophotometer. Please answer the following questions to the best of your ability based on the
information you learned in class.
1. What do the letters FID stand for in a chemical instrumentation laboratory? (1 pt)
2. What are some example of samples that would be commonly analyzed on an FID in a crime laboratory?
(1 pt)
3. A gas chromatograph has three major components. Draw a basic diagram of a gas chromatograph, label
these three major components, and describe the basic function of each. (2 pts)
4. a) What does the term retention time mean? (1 pt)
b) What is the approximate retention time of ethylene glycol (anti freeze) given the analytical data
shown here? (1 pt)
5. a) What do the terms mobile phase and stationary phase mean? (2 pts)
b) In gas chromatography, what makes up the mobile phase and what makes up the stationary phase?
(1 pt)
c) In liquid chromatography, what makes up the mobile phase and what makes up the stationary phase?
(1 pt)
6. Describe, in simple terms as you might explain to a jury, how a mass spectrometer works. (3 pts)
7. Briefly explain what you are looking at in the above data. That is, what do the vertical lines represent?
What does the term m/z mean? (2 pts)
8. What does the term “spectroscopy” mean? Provide two example of chemical instrumentation that uses
spectroscopic techniques. (2 pts)
9. Explain the difference between absorption and emission spectroscopy. Make sure you clearly explain
what happens to electrons in each. Also, provide an example of an instrument that utilizes absorption
techniques and one that utilizes emission techniques. (3 pts)
10. a) Describe what is shown in the instrumental data given below. (2 pts)
b) What instrument provided the data above? (1 pt)
11. What is an ATR head and where would you find one in the chemical instrumentation laboratory? (1 pt)
12. What type of samples would a scientist analyze on an AAS (Atomic Absorption Spectrophotometer)?
(1 pt)