skip navigation

PUBLICATIONS

Register for Latest Research

Stay Informed
Register with NCJRS to receive NCJRS's biweekly e-newsletter JUSTINFO and additional periodic emails from NCJRS and the NCJRS federal sponsors that highlight the latest research published or sponsored by the Office of Justice Programs.

NCJRS Abstract

The document referenced below is part of the NCJRS Virtual Library collection. To conduct further searches of the collection, visit the Virtual Library. See the Obtain Documents page for direction on how to access resources online, via mail, through interlibrary loans, or in a local library.

 

NCJ Number: 136034 Find in a Library
Title: Direct Analysis for Cocaine in Urine by High-Performance Liquid Chromatography (HPLC) Using a Column-Switching Technique
Journal: Journal of Forensic Sciences  Volume:37  Issue:2  Dated:(March 1992)  Pages:636-639
Author(s): A K Larsen Jr; I R Tebbett
Date Published: 1992
Page Count: 4
Type: Test/Measurement
Format: Article
Language: English
Country: United States of America
Annotation: This article describes a relatively rapid and accurate method for detecting cocaine in urine with very low drug concentrations.
Abstract: Any chromatographic analysis of urine for cocaine requires the use of an efficient extraction procedure, together with a sensitive analytical technique. Column switching has been previously reported to be useful for the preliminary identification of drugs in biological samples such as plasma and vitreous humor. This approach involves the use of a precolumn placed in the injection loop of the high-performance liquid chromatograph in such a way that a sample can be injected onto the precolumn and then flushed with another solvent. The precolumn retains the compounds of interest while the endogenous compounds run to waste. The sample can then be washed by injecting, typically, 0.5 to 1 mL of water, buffer, or organic solvent through the injection system. After flushing, the injector is switched to the inject position, and the mobile phase passes through the precolumn and takes the relatively pure compounds of interest onto the analytical column. This technique eliminates lengthy extraction procedures prior to the chromatographic analysis. The method was used to screen postmortem urine samples for the presence of cocaine and benzoylecgonine. Recoveries of near 100 percent make this an attractive technique for the analysis of very low drug concentrations. The volume of urine injected onto the system can also be increased up to 2 mL, thus concentrating the sample onto the precolumn as an additional step to improve sensitivity. 2 figures and 6 references
Main Term(s): Urinalysis
Index Term(s): Chromatography; Cocaine; Drug testing
To cite this abstract, use the following link:
http://www.ncjrs.gov/App/publications/abstract.aspx?ID=136034

*A link to the full-text document is provided whenever possible. For documents not available online, a link to the publisher's website is provided. Tell us how you use the NCJRS Library and Abstracts Database - send us your feedback.