Rapid Analysis of Cocaine in Saliva by Surface-Enhanced Raman Spectroscopy.

Kathryn Dana,Chetan Shende,Hermes Huang,Stuart Farquharson

doi:10.4172/2155-9872.1000289

Abstract

Increases in illicit drug use and the number of emergency-room visits attributable to drug misuse or abuse highlight the need for an efficient, reliable method to detect drugs in patients in order to provide rapid and appropriate care. A surface-enhanced Raman spectroscopy (SERS)-based method was successfully developed to rapidly measure cocaine in saliva at clinical concentrations, as low as 25 ng/mL. Pretreatment steps comprising chemical separation, physical separation, and solid-phase extraction were investigated to recover the analyte drug from the saliva matrix. Samples were analyzed using Fourier-transform (FT) and dispersive Raman systems, and statistical analysis of the results shows that the method is both reliable and accurate, and could be used to quantify unknown samples. The procedure requires minimal space and equipment and can be completed in less than 16 minutes. Finally, due to the inclusion of a buffer solution and the use of multiple robust pretreatment steps, with minimal further development this method could also be applied to other drugs of interest.

Highlights

Illicit drug use is a growing problem in the United States, with associated detrimental health effects to users that may cause them to seek urgent care
Within approximately the same period, the number of annual emergency-room visits attributable to drug misuse or abuse rose by 52%, and cocaine was detected in 40.3% of all illicit-drug-related admissions [2]
Throughout the development of this method, various aspects were investigated to achieve the detection of 10-50 ng/mL cocaine in saliva

Summary

Introduction

Illicit drug use is a growing problem in the United States, with associated detrimental health effects to users that may cause them to seek urgent care. The number of recent users increased from 8.3 percent in 2002 to 9.4 percent in 2013, an estimated 24.6 million people [1] This figure includes 1.5 million cocaine users. Within approximately the same period, the number of annual emergency-room visits attributable to drug misuse or abuse rose by 52% (between 2004 and 2011), and cocaine was detected in 40.3% of all illicit-drug-related admissions [2]. In order to accurately diagnose and treat patients in emergency room situations, it is critical to identify the cause of admission, e.g., the type of drug present in the patient’s system. Drugs are represented in saliva at concentrations similar to blood plasma [5,6], while saliva is characterized by better sample integrity than urine and can contain both the parent compound and metabolites [7]. Saliva is 99.5% water, making it easy to chemically analyze [8]; and simple saliva collectors are readily commercially available

Methods

Results

Conclusion