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Objective Method for Presumptive Field-Testing of Illicit Drug Possession Using Centrifugal Microdevices and Smartphone Analysis

NCJ Number
Date Published
August 2016
9 pages
This article describes the use of inexpensive polyester-toner, rotation-driven microfluidic devices with a smartphone as a potential alternative for current presumptive colorimetric field-testing of illicit drugs, allowing for an objective and user-friendly image analysis technique for detection.
Current colorimetric presumptive identification of illicit drugs for law enforcement officers’ determination of illegal possession of controlled substances relies solely on the subjective interpretation of color change using drug- or class-specific reactions. In the presumptive field test described in this article, the centrifugal microfluidic platform accommodates simultaneous presumptive testing of material from a single input to multiple reaction chambers, enabling rapid screening. Hue and saturation image analysis parameters are used to define threshold values for the detection of cocaine and methamphetamine as proof-of-principle with 0.25 and 0.75 mg/mL limits of detection, respectively, with nonvolatile reagents stored on-board and smartphone for detection. Reported LODs are lower than those concentrations used in the field. Additionally, the developed objective detection method addresses the testing of drugs with various common cutting agents, including those known to produce false negative and positive results. The effectiveness of this method was demonstrated by successfully identifying the composition of 30 unknown samples. (Publisher abstract modified)
Date Published: August 1, 2016