Cobalt thiocyanate reagent revisited for cocaine identification on TLC

Haddoub, Rose; Ferry, Daniel; Marsal, P.; Siri, Olivier

doi:10.1039/c1nj20234k

Cited by 24 publications

(17 citation statements)

References 19 publications

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“…Raman spectra and powder X‐ray diffraction (PXRD) experiments clearly show that graphite is the source of the black colour; in the red acetone extract corresponding signals of graphite are absent. Thus, the acetone‐soluble material contains Cu 2+ and Fe 3+ ions, SCN − and CocH + which strongly reminds to the above mentioned procedures for the extraction and detection of cocaine and related atropine bases using anionic thiocyanate metal complexes such as [Cr(SCN) 6 ] 3− , [Fe(NCS) 6 ] 3− , [Fe(NCS) 4 ] − , [Co(SCN) 4 ] 2− , [Ni(SCN) 4 ] 2− , but also [BiI 4 ] − (Dragendorff reagent), or [AuCl 4 ] − . The anionic complexes form tight ion‐pairs with the protonated atropine bases (or related molecules), allowing the selective liquid‐liquid extraction using organic solvents.…”

Section: Resultsmentioning

confidence: 67%

“…On the other hand it is well known that anionic transition metal complexes formed from SCN − and metal ions such as Fe 3+ , Co 2+ , Cu 2+ , Hg 2+ can form ion pairs with protonated nitrogen bases such as the alkaloids cocaine or atropine thus enabling liquid(water)‐liquid(organics) extraction methods for isolation and detection of these bases . Related liquid‐liquid extraction (LLE) was also reported for the recovery and detection of metal ions by using SCN − and suitable (large, organic) cations .…”

Section: Introductionmentioning

confidence: 99%

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Copper thiocyanato complexes and cocaine – a case of ‘black cocaine’

Laussmann¹,

Grzesiak

Krest

et al. 2014

Drug Testing and Analysis

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The chemical composition of a black powder confiscated by German customs was elucidated. Black powders are occasionally used as a 'transporter' for cocaine and are obviously especially designed to cloak the presence of the drug. The material consisting of cocaine, copper, iron, thiocyanate, and graphite was approached by analytical tools and chemical modelling. Graphite is added to the material probably with the intention of masking the typical infrared (IR) fingerprints of cocaine and can be clearly detected by powder X-ray diffraction (XRD) and Raman spectroscopy. Cu(2+) and NCS(-) ions, when carefully reacted with cocaine hydrochloride, form the novel compound (CocH)2 [Cu(NCS)4 ] (CocH(+) = protonated cocaine), which has been characterised by single crystal XRD, IR, NMR, UV/Vis absorption and EPR spectroscopy. Based on some further experiments the assumed composition of the original black powder is discussed.

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Section: Resultsmentioning

confidence: 67%

Section: Introductionmentioning

confidence: 99%

Copper thiocyanato complexes and cocaine – a case of ‘black cocaine’

Laussmann¹,

Grzesiak

Krest

et al. 2014

Drug Testing and Analysis

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“…Although unable to isolate the colored complex, Oguri et al proposed an octahedral structure for the cocaine‐cobalt(II) thiocyanate complex with 2 thiocyanate ligands and 2 bis chelating cocaine ligands, based on a stoichiometric study. Another study by Haddoub et al revisited the use of cobalt thiocyanate for the detection of cocaine by applying the reagent to a TLC plate and proposed a hexacoordinated cobalt(II) complex with one bis chelating cocaine molecule, 3 water molecules, and one isothiocyanate ligand (Figure c). Scott modified the cobalt thiocyanate test to differentiate between the cocaine free base and cocaine hydrochloride…”

Section: Chemistry Of Common Color Testsmentioning

confidence: 99%

A review of chemical ‘spot’ tests: A presumptive illicit drug identification technique

Philp

2017

Drug Testing and Analysis

107

121

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Chemical 'spot' tests are a presumptive illicit drug identification technique commonly used by law enforcement, border security personnel, and forensic laboratories. The simplicity, low cost, and rapid results afforded by these tests make them particularly attractive for presumptive identification globally. In this paper, we review the development of these long-established methods and discuss color test recommendations and guidelines. A search of the scientific literature revealed the chemical reactions occurring in many color tests are either not actively investigated or reported as unknown.Today, color tests face many challenges, from the appearance of new psychoactive substances to concerns regarding selectivity, sensitivity, and safety. Advances in technology have seen color test reagents used in digital image color analysis, solid sensors, and microfluidic devices for illicit drug detection. This summarizes current research and suggests the future of presumptive color testing. KEYWORDScolor spot test, illicit drugs, new psychoactive substances, presumptive identification, seized material

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“…For caffeine and benzocaine, ionic currents were overlaid with the background electrolyte ion transfer ( H aq ↔ org + ) and were located >400 mV toward more positive potential values as compared to the transfer potential of cocaine. Especially worth attention is lidocaine, being false positive in colorimetric Scott tests, 47 with Δ org aq Φ 1/2 = 115 mV being far enough from the cocaine transfer potential.…”

Section: Resultsmentioning

confidence: 99%

Electrified Soft Interface as a Selective Sensor for Cocaine Detection in Street Samples

et al. 2018

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A straightforward, direct, and selective method is presented for electrochemical cocaine identification in street samples. The sensing mechanism is based on a simple ion transfer reaction across the polarized liquid–liquid interface. The interfacial behavior of a number of cutting agents is also reported. Interfacial miniaturization has led to improved electroanalytical properties of the liquid–liquid interface based sensor as compared with the macroscopic analogue. The reported method holds great potential to replace colorimetric tests with poor selectivity for on-site street sample analysis.

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Cobalt thiocyanate reagent revisited for cocaine identification on TLC

Cited by 24 publications

References 19 publications

Copper thiocyanato complexes and cocaine – a case of ‘black cocaine’

Copper thiocyanato complexes and cocaine – a case of ‘black cocaine’

A review of chemical ‘spot’ tests: A presumptive illicit drug identification technique

Electrified Soft Interface as a Selective Sensor for Cocaine Detection in Street Samples

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