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Biomedical subjects

W E Brewer

Publications and source records attributed to W E Brewer.

4 recordsLinked to original sources
PubMed2001

Analysis of cocaine, benzoylecgonine, codeine, and morphine in hair by supercritical fluid extraction with carbon dioxide modified with methanol.

Supercritical fluid extraction (SFE) using CO2 modified with methanol (10%) was employed for the extraction of cocaine from human hair. Extraction conditions were developed by using designed experiments to characterize the effects of pressure, temperature, and percent methanol on the recovery of cocaine from hair. When compared to the conventional acid hydrolysis method for hair analysis, SFE was faster and gave higher recoveries. Amounts of cocaine, benzoylecgonine (cocaine metabolite), codeine, and morphine in a hair standard reference material were determined by SFE-gas chromatography/ mass spectrometry (GC/MS) and found to be in agreement with reported levels. Analyses of hair from forensic case studies are also reported.

Carbon Dioxide↗
PubMed1999

Rapid gas chromatographic analysis of drugs of forensic interest.

High-speed gas chromatographic (GC) screening for drugs of forensic relevance is performed using a commercial Flash GC instrument in which the chromatographic column is resistively heated at rates of up to 30 degrees C/s. Temperature programming conditions are varied in an experiment designed to evaluate trade-offs between resolution and analysis time for a mixture of 19 drugs of abuse. All 19 components can be separated with excellent resolution in 90 s. Specific analytes can be analyzed even faster; for example, amphetamine analysis is completed in less than 20 s. Case studies of confiscated street drugs containing amphetamine, cocaine, and heroin are analyzed to evaluate the retention time repeatability. Ten replicate injections over a 2-day period for 3 different drug samples achieved retention time relative standard deviations in the range of 0.48 to 0.81%.

Amphetamine↗
PubMedDate not supplied

The confirmation of volatiles by solid-phase microextraction and GC-MS in the investigation of two traffic fatalities.

A simple, sensitive, and reliable method was developed for the confirmation of nonroutine volatiles in the investigation of two traffic fatalities. Solid-phase microextraction (SPME) fibers were used to extract volatile compounds from the headspace of sample vials; components were subsequently analyzed by gas chromatography-mass spectrometry (GC-MS). In the first case, ethanol and methylene chloride were detected in a urine sample by headspace SPME and GC-MS. The second case involved the analysis of volatile petroleum products from submitted specimens by headspace SPME and GC-MS. In both cases, SPME and GC-MS analyses provided crucial evidence in the investigation of the traffic fatalities.

Accidents, Traffic↗