Residue Analysis Laboratory

About AINW

Archaeological Investigations Northwest Inc. (AINW) is a cultural resources firm established in June 1989. The Residue Analysis Laboratory was established in 1990. AINW conducts field projects throughout the Pacific Northwest, but our focus is Oregon and Washington. The Residue Analysis Laboratory has analyzed artifacts for more then 150 projects from: Arizona, California, Colorado, Idaho, Louisiana, Mississippi, Missouri, Montana, Nevada, North Dakota, Oregon, South Dakota, Texas, Utah, Washington, Wisconsin, and Wyoming.

The Portland office and laboratory facilities of AINW occupy approximately 6,000 square feet of space. Our facilities are secured with an electronic burglary and fire alarm system which activates an audible alarm and alerts a manned switchboard monitor that notifies the police or fire stations.

The Residue Analysis Laboratory

The Residue Analysis Laboratory at AINW uses the technique of cross-over electrophoresis (CIEP, for crossed immunoelectrophoresis), a type of immunoelectrophoresis, to analyze surface residues extracted from stone and other artifacts. CIEP uses an agarose gel platform. Antisera from commercial laboratories are the reactants used to identify the type of animal residue(s) present. The AINW Residue Analysis Laboratory can test for mammal, fish and/or bird residues.

The accuracy and usefulness of the CIEP technique was well established in forensic medicine before being adapted for archaeological applications. In fact, the antisera used by our laboratory, are forensic grade antisera. A 5% amonia solution is applied to each artifact (usually on one side only) in a shallow plastic dish which is then placed in an ultrasonic cleaner for five minutes, and then on a rotator for an additional five minutes. Artifacts too large for the ultrasonic extraction may be placed on the rotator only, but for a longer period of time. The solution is then extracted and placed in a capped vial, so the time the artifacts are needed in-house is quite brief, and they may be returned quickly.

The testing itself is rapid, depending on the number of artifacts and number of antisera ordered. When "positive" reactions are observed, these are reprocessed to confirm the testing accuracy. Controls of known sera are run during the procedure to ensure validity.

AINW provides an easy artifact/residue checklist form showing residue testing options.

Recommended Handling

We recommend that artifacts submitted for analysis not be handled, avoiding possible contamination. Ideally, artifacts should be placed into closable plastic bags without being handled. For artifacts from subsurface contexts we recommend that 0.25 gram of sediment from the appropriate stratum be submitted as a sample for analysis in addition to the artifacts. We have had good results on artifacts from both surface and subsurface contexts and from curated collections.

Our Residue Analysis Reports

• Each of our Residue Analysis Reports include:
• A letter report summarizing the results.
• Lists of the artifacts tested.
• The types of antisera used.
• A brief description of what kinds of animals selected antisera may be expected to represent.
• A description of the artifacts with positive reactions, if any.
• A brief description of our testing and storage procedures.
• A chart of the results is included with the report.

A standardized, more detailed report with description of the laboratory methods and procedures is also included for each project. Typically, we provide reports as text on paper. We can also deliver reports on computer disk in a number of formats, upon request.

Site last modified: December 23, 2005

For more information, please email us: ainw@ainw.com