Combined Colorimetric and Electrochemical Measurement Paper-Based Device for Chemometric Proof-of-Concept Analysis of Cocaine Samples

Abstract

Cocaine (COC) is one of the most widely consumed illegal drugs around the world. Street COC is commonly adulterated with pharmaceutical compounds that mimic or intensify the COC's sensory effect. Adulteration is performed to increase the profit of criminal organizations and each one has their own way of doing it. Therefore, determining the composition of seized COC samples (chemical profile) provides evidence for the police to track criminal organization networks and their activity patterns. Using filter paper as a substrate, we developed a multiple detection paper-based analytical device (PAD) that combines colorimetric and electrochemical measurements to discriminate COC samples according to adulterant's content. A regular graphite lead modified with a gold film made from Au leaf (graphite/Au) to improve electron transfer was used as a working electrode. Silver and Ag/AgCl were used as auxiliary and reference electrodes, respectively. The colorimetric device was patterned using a laser cutter and coupled to the electrochemical device using a double-sided tape, allowing simultaneous analysis to gather more analytical information about COC samples. Graphite/Au was characterized by scanning and transmission electron microscopies and electrochemical assays. The simultaneous colorimetric and electrochemical analyses combined to principal component analysis improved the analytical characterization of COC trial samples and provided a fast discrimination based on the assembled database.

Sensitive Multi‐Detection of Escherichia coli by Quartz Crystal Microbalance with a Novel Surface Controllable Sensing Method in Liquid Organic Fertilizer Produced by Sewage Sludge

“…Detection of these pathogens with conventional methods involves complex, time‐consuming and costly processes that cannot be carried out in the field [60] . Techniques that combine colorimetric paper‐based biosensors [61] with paper‐based electrochemical biosensors [62] have recently become very popular due to their portability, speed, cost, and field availability [63] . Magnetic quantum dots, [64] which may be used instead of fluorescent microspheres in the controlled removal method with synthetic DNAs, which has been used for the first time in this study, not only provide magnet control of captured pathogens, but also provide visual verification.…”

Dual-mode ion-selective electrodes and distance-based microfluidic device for detection of multiple urinary electrolytes

“…The dual-mode sensing with colorimetric detection and electrochemical detection using cyclic voltammetry on a μPAD has been demonstrated in several works for environmental and criminal applications. 26,27 Likewise, colorimetric and electrochemical detection can be accompanied each other to allow highly sensitive analysis of various ions that cannot be detected by a color change for clinical applications to extend the working range for ion of interest. In a recent work, potentiometric K + -ISE on transparency polyethylene terephthalate (PET) substrate using in-house stencil printing method and paper-based device was combined.…”

Rapid Formation of Nanoclusters for Detection of Drugs in Urine Using Surface-Enhanced Raman Spectroscopy

“…Surface-enhanced Raman spectroscopy (SERS) has been used to detect a variety of molecules [ 6 , 7 , 8 , 9 , 10 ] because SERS-based methods only need a small sample and take a few seconds to achieve the multiplexed detection of molecules with high sensitivity. Many studies have reported the SERS detection of drugs, including cannabinoid [ 11 ], cocaine [ 12 , 13 , 14 , 15 , 16 , 17 ], flunitrazepam [ 18 ], alpha-methyltryptamine [ 19 ], heroin [ 17 , 20 ], ketamine [ 21 ], morphine [ 13 , 22 ], benzodiazepine [ 23 ], methamphetamine [ 13 , 24 , 25 , 26 , 27 , 28 , 29 , 30 ], amphetamine [ 31 ], opioid [ 32 ], 3,4-methylenedioxymethamphetamine (MDMA) [ 25 , 27 , 28 , 33 ], 4-MMC [ 34 , 35 ], MC [ 25 ], barbiturate [ 36 ], and sulfa drugs [ 37 ]. While the plasmonic properties of nanostructured substrates or nanoparticles used for SERS measurements is critical for the sensitive detection of molecules, it has been demonstrated that sample pretreatment is also very important for the SERS detection of drugs in biological samples such as urine [ 14 , 25 , 27 ,…”