Fingerprint matching

Arnold, R. J. Reilly, J. P. Fingerprint matching of E. coli strains with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry of whole cells using a modified correlation approach. Rapid Commun. Mass Spectrom. 1998,12,630-636. 

In cases of sexual assault, tiny samples of DNA in blood, semen, skin, or hair found on the victim may be purified and the amount of DNA increased by the use of a polymerase chain reaction to produce quantities large enough to analyze. Since DNA is as specific to a person as fingerprints, matching the DNA of a perpetrator to a sample found on a victim is considered to be proof of contact. The Federal Bureau of Investigation (FBI)... 

Currently, rapid and unambiguous identification of tropane alkaloids is routinely accomplished by GC-MS by fingerprint matching, comparing the MS spectra with... 

Scientists can then determine the exact proportions of the elements present. This method gives scientists a fingerprint of the elements in the sample. If the fingerprint matches materials that were not available when the work was supposedly created, then the artwork is a fake. 

The identification of polymers is largely done by fingerprint matching. Representative spectra of the most important commercial polymers are included here for the convenience of the reader (Figures 2-10). They are grouped by structure to emphasize the features that chemically related polymers have in common and to demonstrate the distinctive identifying characteristics of each polymer class,... 

Peak detection is an important step in the identification process. Sometimes only a few experimental peptide masses in the fingerprint match the theoretical masses, and therefore the failure to detect a relevant peak can hinder the correct identification of a protein. However, if too many false peaks are considered, this may lead to erroneous database matches causing false identifications, as well as increasing search duration. Furthermore, it is important to precisely determine the peptide masses. 

A relative newcomer to the atomic emission instruments commercially available, LIBS has some significant advantages over the other emission techniques and over ICP-MS and XRF. It is virtually nondestructive and often can be used with no sample preparation. It has the ability to detect all of the elements in virtually any sample type. Versions are available that are field-portable, and versions are available for remote/standoff analysis. Instrumentation is relatively inexpensive. The major disadvantage is the lack of LIBS spectral libraries for easy fingerprint matching, but that is being remedied as the instrumentation becomes more common. 

At least in principle, comparison of DNA fingerprints can determine the guilt or innocence of a suspect beyond a reasonable doubt. If the two fingerprints differ, the suspect is innocent. Conversely, if the fingerprints match perfectly, the odds that the suspect is guilty are about 80 billion to one. 

---