High-Performance Liquid Chromatography with Column Switching for the Determination of Cocaine and Benzoylecgonine Concentrations in Vitreous Humor
Logan, BK
Senior research associate, Department of Toxicology and Chemical Pathology, University of Tennessee, Memphis, TN: currently, laboratory director, State Toxicology Laboratory, University of Washington, Seattle, WA.

Stafford, DT
Laboratory director, Department of Toxicology and Chemical Pathology, University of Tennessee. Memphis, TN.


Abstract
A sample concentration technique was adapted for the determination of cocaine and benzoylecgonine (BE) concentrations in vitreous humor. Vitreous humor (0.5 mL) was diluted 1:1 with water and applied through a filter onto a 3-cm preconcentration column. Following a simple wash step, the analytes were flushed directly onto a reversed-phase analytical high-performance liquid chromatography (HPLC) system. Absolute recoveries were high (above 90%) and the chromatograms were free from interference. Analysis for the drug and its breakdown product was performed using ultraviolet (UV) visible photodiode array detection, which allowed confirmation of peak identity. Recognizable UV spectra could be measured with as little as 20 ng on column. Comparison of the drug levels in 27 blood and vitreous humor samples showed that, while there was only a low correlation between the blood and vitreous concentrations (R = 0.70), vitreous cocaine and BE determinations were good indicators of antemortem cocaine use. In almost all cases, the vitreous BE concentrations were higher than the cocaine concentrations. The technique was easy to perform and the vitreous samples were especially compatible with this low-labor analytical procedure.

Keywords:
benzoylecgonine, benzoylecogonine, cocaine, forensic science, HPLC, postmortem drug distribution, toxicology, vitreous humor

Paper ID: JFS356901303

ASTM International is a member of CrossRef.
Author Logan BK, Stafford DT Title High-Performance Liquid Chromatography with Column Switching for the Determination of Cocaine and Benzoylecgonine Concentrations in Vitreous Humor Symposium , Committee on