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The complex, bis(N,N-diethyl-4-methyl-4-piperazine-1-carboxamide) tetrakis(isothiocyanato-κN)cobalt(II) (N,N-diethyl-4-methyl-4-piperazine-1-carboxamide = diethylcarbamazine), (C10H22N3O)2[Co(NCS)4], is presented. This complex is a blue precipitate, insoluble in water but soluble in organic solvents, that is formed from the reaction of diethylcarbamazine citrate, a protonated tertiary amine, with cobalt(II) and thiocyanate. This reaction, in the form of the Scott test, is a common presumptive test for cocaine hydrochloride. The known cobalt compound, [K2Co(NCS)4]·3H2O, has a deep-blue coloration due to the tetrahedral [Co(NCS)4]2- that is also present in the ion pair with bulky amines, and is similar to the color of other tetrahedral cobalt(II) complex ions, such as [CoCl4]2-. The structure is consistent with a previous proposal that a hydrophobic ion pair formed between [Co(NCS)4]2- and two protonated molecules of cocaine is responsible for the blue hydrophobic products formed by cocaine in the Scott test. [ABSTRACT FROM AUTHOR]

As drug overdose deaths across the United States continue to rise, there is increasing interest in field testing of illicit substances. This work discusses a paper‐based analytical device (idPAD) that can run a library of 12 colorimetric tests at the same time, each detecting different chemical functional groups and materials found in illicit drugs, distractor substances, and cutting agents. The idPAD requires no electricity, costs less than $2 USD, and requires minimal training to operate. The results of the 12 tests form a color barcode which is "read" by comparison to standard images. The accuracy of the idPAD was assessed using samples of heroin, cocaine HCl, crack, and methamphetamine at concentrations of 25%–100% in a lactose matrix, as well as pure lactose. Based on 840 "reads" by three different users, the idPAD showed 95% sensitivity and 100% specificity for detecting these drugs; the most common error was mistaking cocaine HCl for crack or crack for cocaine HCl. In a second step, samples of heroin, cocaine, and methamphetamine (n = 30) and distractor substances (pharmaceuticals, cutting agents, and other illicit drugs, n = 64) were tested by two readers, yielding a sensitivity of 100% and specificity of 97%. Targeted substances were detected reliably at 55–180 μg/lane, and the idPAD was found to be stable for at least 3 months when stored at room temperature. The library approach used in the idPAD may provide the accuracy and robustness necessary for a presumptive field drug test. [ABSTRACT FROM AUTHOR]