Recoveries of trace pseudoephedrine and methamphetamine residues from impermeable household surfaces: implications for sampling methods used during remediation of clandestine methamphetamine laboratories.
Evaluation of the risk posed by contaminants present during and after decontamination of clandestine methamphetamine laboratories requires a connection between the levels of contaminants measured and those actually present at the scene. The recoveries of pseudoephedrine and methamphetamine from glass, stainless steel, and a range of impermeable surfaces likely to be found in a clandestine laboratory were examined, using GC-MS of derivatized samples as the analytical method. When surfaces had been cleaned prior to drug deposition, wiping with water-dampened filter paper can recover 60-80% of pseudoephedrine immediately after deposition, and at least 50% of the pseudoephedrine still present on a surface after 2 days when deposited at a surface concentration of 2.5 microg/100 cm(2). Wiping with methanol-dampened filter paper could recover 60-90% of the methamphetamine immediately after deposition, and could recover at least 50-60% of the methamphetamine still present after 2 days when 0.6 microg/100 cm(2) was initially deposited on the surface. Recoveries were lower for surfaces that had not been pre-cleaned. Methamphetamine and pseudoephedrine showed significant volatility in both the free base and hydrochloride forms, with experiments in an enclosed format showing up to half the recovered drug being present on a glass plate held about 4mm above a substrate contaminated with one of the drugs at the above surface concentrations after 2 days. It is therefore important to remove any visible bulk contaminants and remove obvious pseudoephedrine or methamphetamine-contaminated surfaces prior to heating, ventilation or sealing of a clandestine laboratory to avoid redistribution of material around the site. A revised method for pseudoephedrine analysis was developed that could also detect the pseudoephedrine-formaldehyde adduct that can form from trace pseudoephedrine present at clandestine laboratories.
Abdullah
A F Lim
AF
Forensic Science Programme, Department of Chemistry, The University of Auckland, Private Bag 92019, Auckland, New Zealand.
Miskelly
Gordon M
GM
D052918:Environmental Restoration and Remediation / Q000379:methods*; D006798:Housing; D007753:Laboratories; D008694:Methamphetamine / Q000032:analysis / Q000737:chemistry / Q000302:isolation & purification*; D010080:Oxazoles / Q000032:analysis / Q000737:chemistry; D010539:Permeability; D054199:Pseudoephedrine / Q000032:analysis / Q000737:chemistry / Q000302:isolation & purification*; D013499:Surface Properties
D010080:Oxazoles; C064210:oxazolidine; D008694:Methamphetamine; D054199:Pseudoephedrine