title: Simple and Sensitive Molecularly Imprinted Polymer - Mn-Doped ZnS Quantum Dots Based Fluorescence Probe for Cocaine and Metabolites Determination in Urine.
abstract: A new molecularly imprinted polymer (MIP)-based fluorescent artificial receptor has been prepared by anchoring a selective MIP for cocaine (COC) on the surface of polyethylene glycol (PEG) modified Mn-doped ZnS quantum dots (QDs). The prepared material combines the high selectivity attributed to MIPs and the sensitive fluorescent property of the Mn-doped ZnS QDs. Simple and low cost methods have therefore been optimized for assessing cocaine abuse in urine by monitoring the fluorescence quenching when the template (COC) and also metabolites from COC [benzoylecgonine (BZE) and ecgonine methyl ester (EME)] are present. Fluorescence quenching was not observed when performing experiments with other drugs of abuse (and their metabolites) or when using nonimprinted polymer (NIP)-coated QDs. Under optimized operating conditions (1.5 mL of 200 mg L(-1) MIP-coated QDs solution, pH 5.5, and 15 min before fluorescence scanning) two analytical methods were developed/validated. One of the procedures (direct method) consisted of urine sample 1:20 dilution before fluorescence measurements. The method has been found to be fast, precise, and accurate, but the standard addition technique for performing the analysis was required because of the existence of matrix effect. The second procedure performed a solid phase extraction (SPE) first, avoiding matrix effect and allowing external calibration. The limits of detection of the methods were 0.076 mg L(-1) (direct method) and 0.0042 mg L(-1) (SPE based method), which are lower than the cutoff values for confirmative conclusions regarding cocaine abuse.
authors: Department of Analytical Chemistry, Nutrition and Bromatology, Faculty of Chemistry, University of Santiago de Compostela , Avenida das Ciencias, s/n, 15782 - Santiago de Compostela, Spain.
authors: María Pilar
authors: MP
authors: Chantada-Vázquez
authors: Department of Analytical Chemistry, Nutrition and Bromatology, Faculty of Chemistry, University of Santiago de Compostela , Avenida das Ciencias, s/n, 15782 - Santiago de Compostela, Spain.
authors: Juan
authors: J
authors: Sánchez-González
authors: Department of Analytical Chemistry, Nutrition and Bromatology, Faculty of Chemistry, University of Santiago de Compostela , Avenida das Ciencias, s/n, 15782 - Santiago de Compostela, Spain.
authors: Elena
authors: E
authors: Peña-Vázquez
authors: Department of Pathologic Anatomy and Forensic Sciences, Faculty of Medicine, University of Santiago de Compostela , Rúa de San Francisco, s/n, 15782 - Santiago de Compostela, Spain.
authors: María Jesús
authors: MJ
authors: Tabernero
authors: Department of Pathologic Anatomy and Forensic Sciences, Faculty of Medicine, University of Santiago de Compostela , Rúa de San Francisco, s/n, 15782 - Santiago de Compostela, Spain.
authors: Ana María
authors: AM
authors: Bermejo
authors: Department of Analytical Chemistry, Nutrition and Bromatology, Faculty of Chemistry, University of Santiago de Compostela , Avenida das Ciencias, s/n, 15782 - Santiago de Compostela, Spain.
authors: Pilar
authors: P
authors: Bermejo-Barrera
authors: Department of Analytical Chemistry, Nutrition and Bromatology, Faculty of Chemistry, University of Santiago de Compostela , Avenida das Ciencias, s/n, 15782 - Santiago de Compostela, Spain.
authors: Antonio
authors: A
authors: Moreda-Piñeiro
mesh_terms: D002138:Calibration; D003042:Cocaine / Q000031:analogs & derivatives* / Q000652:urine*; D005456:Fluorescent Dyes / Q000737:chemistry*; D006801:Humans; D057230:Limit of Detection; D008345:Manganese / Q000737:chemistry*; D054802:Molecular Imprinting / Q000379:methods*; D011108:Polymers / Q000737:chemistry*; D045663:Quantum Dots; D013050:Spectrometry, Fluorescence; D015813:Substance Abuse Detection / Q000379:methods; D013440:Sulfides / Q000737:chemistry*; D017967:Zinc Compounds / Q000737:chemistry*
chemical_list: D005456:Fluorescent Dyes; D011108:Polymers; D013440:Sulfides; D017967:Zinc Compounds; D008345:Manganese; C005618:benzoylecgonine; D003042:Cocaine; C031238:zinc sulfide; C034524:ecgonine methyl ester