Related Experiment Video
Updated: Oct 2, 2026

Nano-fEM: Protein Localization Using Photo-activated Localization Microscopy and Electron Microscopy
Published on: December 3, 2012
The storage of forensic urine drug specimens as dry stains: recovery and stability
1Corning National Center for Forensic Science, Baltimore, MD 21227, USA.
Abstract:
The feasibility of storing forensic urine drug specimens as dry stains on Whatman #3 paper was studied by evaluating the stability of the drugs and recovery from the stains. Drug stains prepared from urine (3 mL) were stores at -20 degrees C, 4 degrees C, and at room temperature for a period of 12 weeks. The study included: amphetamine, benzoylecgonine, 11-nor-delta-9-tetrahydrocannabinol-9-carboxylic acid (THC-COOH), morphine, and phencyclidine (PCP) as examples of the HHS regulated drug classes. Drugs were eluted from the stains as follows: methanol:saline (1:1) for PCP and THC-COOH, saline for benzoylecgonine and carbonate/bicarbonate buffer pH 9.2 for amphetamine and morphine. Stains were eluted from the support matrix (Whatman #3 filter paper), extracted and analyzed by gas chromatography/mass spectrometry. All drugs were stable under all of the storage conditions except the THC-COOH urine stain stored at room temperature that degraded to zero after 12 weeks. Therefore, drug stains when kept frozen or refrigerated appear to provide a viable means for storing positive urine specimens.
Related Concept Videos
Fixation and Sectioning
The simplest type of preparation is the wet mount, in which the specimen is placed in a drop of liquid on the slide. A liquid specimen can be directly deposited on the slide using a dropper. Solid specimens, such as skin scraping, can be placed on the slide before adding a drop of liquid to prepare the wet mount. Sometimes the liquid is simply water, but stains are often added...
Preparation of Samples for Electron Microscopy
Sample Handling
Samples should be transported carefully from collection points to the laboratory. They should be properly sealed and clearly labeled to prevent cross-contamination. To preserve the sample integrity, optimal temperature conditions during transport are essential. This could involve using...
Drug Product Stability
Urine Studies I: Urinalysis

