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Mass Spectrometry in Forensic Science 169

detecting the origin of illicit waste discharge. A common and the other from Californian crude oil. The latter source
issue is to link the constituents of, for instance, an oil spill had probably been released in to the sea from storage tanks
sample with its original source. GC or GC/MS are usually by an earthquake that had taken place in the area 40 years
used to do the analysis when the individual hydrocarbons earlier.
are separated and displayed on a chromatogram, whose
pattern is compared with that of the suspected original SEE ALSO THE FOLLOWING ARTICLES
source. A major problem in such a survey, however, is
that some time usually has passed between the waste dis-
DNA TESTING IN FORENSIC SCIENCE • GAS CHROMATO-
charge and the specimen collection. Owing to weathering
GRAPHY • ION KINETICS AND ENERGETICS • LIQUID
by evaporation and biodegradation of the components dur-
CHROMATOGRAPHY • MASS SPECTROMETRY • POLLU-
ing this period, the composition of the oil spill may have
TION,ENVIRONMENTAL • SPECTROSCOPY IN FORENSIC
changed to the extent that it bears only limited similarities
SCIENCE • TOXICOLOGY IN FORENSIC SCIENCE
with that of the origin.
Monitoring the contents of stable isotopes by MS in the
whole sample or in its individual constituents after GC has BIBLIOGRAPHY
isolated them is an approach used to get around the weath-
ering problems. It has been shown that the most common Currell, G. (2000). “Mass spectrometry systems.” In “Analytical Instru-
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stable isotope parameter used (i.e., the C/ C ratio) may mentation, Performance, Characteristics and Quality,” pp. 181–191,
be specific for a source and not very much influenced by John Wiley & Sons, New York.
weathering effects. Technically, the analysis is done after Fifield, F. W., and Kealey, D. (2000). “Mass spectrometry.” In “Principles
andPracticeofAnalyticalChemistry,”5thed.,pp.426–440,Blackwell
the test material has been combusted to carbon dioxide and Scientific, Oxford.
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water, and the C/ C ratio is then determined in the car- Keto, R. O. (1995). “GC/MS data interpretation for petroleum distil-
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bondioxidefractionbyMS.Todeterminethe C/ Cratio late identification in contaminated arson debris,” Journal of Forensic
of the individual components of a sample, they are sepa- Sciences 40, 412–423.
ratedbyGC,eachisolatedhydrocarbongoesdirectlyintoa Masucci, J. A., and Caldwell, G. W. (1995). “Techniques for gas chro-
matography/mass spectrometry.” In “Modern Practice of Gas Chro-
combustion chamber, and the carbon dioxide, after having
matography,” 3rd ed. (R. L. Grob, ed.), pp. 323–391, John Wiley &
been freed from water, enters the mass spectrometer. An il- Sons, New York.
lustration of the use of this tool to identify oil spill sources McNair, H. M., and Miller, J. M. (1998). “Special topics.” In “Basic Gas
is the stable isotopes of samples taken from the area of Chromatography. Techniques in Analytical Chemistry,” pp. 153–163,
Prince William Sound several years after the Exxon Valdez John Wiley & Sons, New York.
Wasels, R., and Belleville, F. (1994). “Gas chromatographic–mass spec-
disaster. The isotope distribution in the samples as mea-
trometric procedures used for the identification and determination
sured on the bulk contents correlated with two distinct ori- of morphine, codeine and 6-monoacetylmorphine,” Journal of Chro-
gins of the oil spill: one coming from the Exxon Valdez oil matography A 674, 225–234.