To the Contemporary World

  1. Court witness. The forensic chemist is often called to testify as an expert in civil and criminal cases. In criminal cases, forensic chemists may be asked to explain the identification (chemical test, analytical instrumentation, reliability of test, etc.) of a drug found in the body of a deceased person. In civil cases, he/she may testify in cases involving water quality, product liability, etc.

  2. Driving while intoxicated (DWI) and the Breathalyzer . The Breathalyzer has been shown to be a reliable, noninvasive instrument for forensic alcohol analysis. The chemistry of the Breathalyzer involves the reduction of orange potassium dichromate by ethanol contained in the breath of the test subject.

    3C 2 H 5 OH(g) + 2K 2 Cr 2 O 7 (aq) + 8H 2 SO 4 (aq)--->

  3. 3CH 3 COOH(l) + 2Cr 2 (SO 4 ) 3 (s) + 2K 2 SO 4 (aq) + 11H 2 O(l)

    The reduction product, Cr 2 (SO 4 ) 3 , is a green solid. The Breathalyzer scale provides a percent blood-alcohol concentration. A value of 0.10% is the minimum amount for being legally intoxicated and subject to a DWI conviction (see Demonstration 1 in Chemistry in Medicine module).

  4. Computers. In forensic laboratories computers can collect and store voluminous quantities of laboratory data. Minicomputers link local crime laboratories via telephone lines to large, perhaps national, computers. Such systems facilitate the collection of reference information on glass, paint, tire prints, shoe prints, and headlights. Computers can help with interpretation of data; instead of manually comparing and subjectively evaluating chromatograms of drugs, accelerants, paints, plastics, etc., computers can be used to precisely scrutinize and compare samples to references by pattern recognition algorithms.

  5. Literature. As forensic science developed in police laboratories, fiction writers began to base some characters in their novels on forensic scientists. Sherlock Holmes is perhaps the most popular fictional detective. He is noted for solving crimes by the application of science. He recognized the odor of iodoform, the black mark of silver nitrate on a finger, and readily confirmed Watson's diagnosis concerning the "pleasant almondy odor" of a "small blue bottle" as prussic acid in Arthur Conan Doyle's The Veiled Lodger. The chemical discovery of which Holmes is most proud is described in A Study in Scarlet. "`I've found it! I've found it!' he shouted, running toward us with a test-tube in his hand. `I have found a reagent that is precipitated by hemoglobin and by nothing else.' In an instant, the contents assumed a dull mahogany color, and a brownish dust was precipitated to the bottom of the glass jar." [See Gillard, R. D. (1976). Sherlock Homes: Chemist. Education in Chemistry, p. 10.] However, Arthur Conan Doyle was surprisingly uninformed in science and Sherlock Holmes, as a scientific detective, perhaps was not really the scientist we thought. [See Asimov, I. (1983). The roving mind, Part IV Science Opinion, "Sherlock Holmes as a Chemist," Prometheus Books, Buffalo, NY.]

    Ian Rae [Dustcoats in dust jackets. (1983). Chemistry in Britain, 19, 565.] discusses other authors who use chemistry in their novels, including Austin Freeman whose Famous Cases of Dr. Thorndyke (Hodder and Stoughton, London, 1929; reprinted 1965) contains much chemistry. In this book, Freeman describes the Marsh test for arsenic, including its distinction from antimony (using hypo-chlorite), and a description of an attempted poisoning by atropine that relied on secretion of this substance in eggs of pigeons that had been fed belladonna.

    Dorothy Sayers apparently had learned some chemistry and used it in several of her novels. Strong Poison (Gollancz Publisher, London, 1930) deals with the ability of a practiced arsenic eater to withstand a dose that kills his victim. There is also an account of the Marsh test for arsenic. In The Documents in the Case, Sayers and Robert Eustace base the apprehension of a murderer on the stereoisomers in poisonous mushrooms. The poisoning occurred with the racemic mixture, indicating the death was not accidental.

    Forensic chemistry is mentioned in other poisoning whodunits. Thallium poisoning was discussed in Agatha Christie's The Pale Horse (Fontana, London, 1972; first published 1961). Ngaio Marsh's Final Curtain (Middlesex Penguin, 1961; first published 1947) gives a sketchy description of the chemistry of embalming and the flame test for thallium.

    Many of J. J. Connington's stories involve forensic chemistry. Connington was the pen name of A. W. Stewart, a professor of chemistry at Queen's University (Belfast, 1919-1944). The Counsellor (Hodder and Stoughton, London, 1939) discusses mescaline trances and Jack in the Box (Hodder and Stoughton, London, 1944) contains a poisoning with nickel tetracarbonyl.

    >Forensic science techniques have been used in several recent fictional and nonfictional books. The following is a brief listing:

    Ted Bundy: The Killer Next Door by Steven Winn

    The Man Who Killed Boys by Clifford Linedecker

    The French Connection by Robin Moore

    Coma by Robin Cook

    Fatal Vision by Joe McGinnis

    The Third Deadly Sin by Lawrence Saunders

    The Michigan Murders by Edward Keyes

    The Boston Strangler by Gerald Frank

    The Wood-Chipper Murder by Arthur Herzog

  6. Community Resources

    a. Guest speaker from a local police department crime laboratory, the state crime laboratory, or the local medical examiner's office.

    b. Field trip to the local police department or crime laboratory.

    c. Guest speaker on uses of forensic chemistry in archaeology.

    d. Invite a race track tester or large-animal veterinarian for a classroom discussion on testing for drugs in horses.

    e. A museum curator is generally a good person to discuss art frauds.