News
LABORATORY PROFILE Forensics on the wild side A fur coat, some feathers, a package of nontraditional medicine—each item is potential evidence of a crime. The victims in these cases are any of thousands of different species of wildlife protected in the U.S. by federal and state laws or internationally by the Convention on the International Trade of Endangered Species (CITES). Since 1989, the National Fish and Wildlife's Forensic Laboratory (Ashland, OR)— the only wildlife crime lab in the world—has been a key element in enforcing these laws. It has also taken a lead in pioneering analytical methods for this unique area of forensics. Each year, the wildlife lab receives about 5000 items to investigate, including evidence seized in other countries under CITES, says Ed Espinoza, deputy director of the lab. In some cases, the evidence arrives as nearly intact animal remains; and the lab's pathology section tries to establish how the creature died. In other instances, the evidence is only part of the animal, such as a paw, a feather, or an animal skin. These pieces are examined in the morphology section. Reference collections of fur hairs skins and even whole preserved animals and birds aid in matching these bits and pieces to a particular species Sometimes it is not clear whether the item is from an animal, let alone one protected by law. On the day Analytical Chemistry visited tht lab, a bab containing some 80 different Chinesemade medicines, which had been seized by U.S. Fish and Wildlife agents, had just arrived. According to Espinoza, each medicine would be tested by four or five analytical methods to be sure none of the drugs were derived from an endangered species.
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For example, the keratin in rhinoceros horn is identified by a characteristic FT-IR fingerprint spectrum. Espinoza adds that finding ways to identify more species is a major challenge for the lab. Many of the samples requiring identification are tested in the serology laboratory, where protein and DNA techniques are used to characterize the species and even the individual animal. Samples are first classed by famiiy (such as feline, deer, or bear) by testing for an immunological reaction against the appropriate antisera. Next comes species identification based on the gel electrophoresis analysis of enzymes such as superoxide dismutase and glucose phosphate isomerase; as a rule, four different enzymes involved in the Krebs cycle or glycophosphorylation are mapped. Standard DNA analysis also identifies species and, if tiiere is enough genetic variation can tag individual animals Unfortunately says Espinoza "The more endangered the species the less variation we see in the DNA " Rare black-footed ferrets for example share almost identical DNA When serology fails to identify a species, the lab turns to other chemical markers in its criminalistics lab. For example, musk deer fall onto the evolutionary periphery of the deer family, and the antisera test fails for this species. The lab developed an alternative method that identifies these animals by GC/MS detection of the unique odorant muskone. In anodier example, black bear gall bladders, used in certain traditional Asian medicines, can be identified through HPLC with UV detection of three unique bile acids. (The protein and DNA markers for the gall bladders are generally degraded by the bile acids.) Of course, most pieces of evidence require contributions from all the lab's sections. When dead eagles were found near Kodiak, Alaska, a GC/MS analysis of the stomachs identified the sedative pentobarbital, and antisera tests of the contents were positive for feline. It turned out that the birds were feeding on euthanized cats being disposed of in a landfill by the local humane society, and thus they indirectly consumed toxic levels of pentobarbital. Method development is also part of the lab's agenda. About $100,000 is allocated each year for research, but the lab has stretched those dollars through the help of numerous community volunteers who aid with tasks such as preparing standard
Analytical Chemistry News & Features, April 1, 199
solutions. (Volunteers are kept away from criminal evidence.) Recently, Espinoza and his colleagues stumbled onto a new method for species identification based on LC/MS analysis of hemoglobin. Espinoza was searching for a method to characterize cyanohemoglobin when he noticed that the molecular weights of the a and B protein chains varied with animal species or family. In retrospect, it made sense because the a and P chains represent two different genes covering about 5000 DNA base pairs, he says The LC/MS method offers species identifications in less than one day versus three days for DNA analysis However Espinoza "the method isn't ready for court yet" He is still searching for a method that detects cyanide bound to hemoglobin The lab is also developing a method for characterizing soils using FT-IR. Spectra of soil samples are recorded both neat and after burning off all the organics in a furnace. The difference between the two is a measure of the soil's organic component, which characterizes the soil type, says Espinoza. The lab is now building a library of soil types from the data. Of course, not all items received by the lab originate from a crime involving wildlife. Espinoza opens a drawer and pulls out what was claimed to be a tiger penis, a supposed aphrodisiac that sells for around $2000. In fact, it is a fraud. Morphology and protein/DNA analysis show that it was fabricated from cow and dog parts, then carved to look like a tiger penis. Alan Newman
