Development and application of molecularly imprinted polymer – Mn-doped ZnS quantum dot fluorescent optosensing for cocaine screening in oral fluid and serum

A molecularly imprinted polymer – Mn-doped ZnS quantum dot-based fluorescence probe for cocaine abuse screening has been prepared and applied to complex samples such as serum and oral fluid. The fluorescent sensing material was prepared by anchoring a selective MIP for COC on the surface of polyethy...

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Bibliographic Details
Published in:Talanta (Oxford) 2018-05, Vol.181, p.232-238
Main Authors: Chantada–Vázquez, María Pilar, de–Becerra–Sánchez, Carolina, Fernández–del–Río, Alba, Sánchez–González, Juan, Bermejo, Ana María, Bermejo–Barrera, Pilar, Moreda–Piñeiro, Antonio
Format: Article
Language:English
Subjects:
Cocaine
Mn-doped ZnS quantum dot
Molecularly imprinted polymer
Oral fluid
Serum
Spectrofluorimetry
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Summary:A molecularly imprinted polymer – Mn-doped ZnS quantum dot-based fluorescence probe for cocaine abuse screening has been prepared and applied to complex samples such as serum and oral fluid. The fluorescent sensing material was prepared by anchoring a selective MIP for COC on the surface of polyethylene glycol (PEG) modified Mn-doped ZnS quantum dots (QDs). Simple and low cost methods have thus been optimized for assessing cocaine abuse in serum and oral fluid by monitoring fluorescence quenching when cocaine (COC) is present (optimized operating conditions with 1.5mL of 200mgL-1 MIP-coated QDs solution, pH 5.5, and 15min before fluorescence scanning). The matrix effect was found to be important when analyzing oral fluid and serum, and several strategies based on centrifugation for oral fluid and solid phase extraction (SPE) for serum were explored. Two analytical methods were developed for oral fluid. The first one (direct method) requires a centrifugation step (6°C, 4000rpm, 20min) to avoid the matrix effect, and allows for cocaine determination by using an aqueous calibration (1:20 dilution). The second method was developed for oral fluid sampled by Salivette devices, and also requires a further centrifugation (6°C, 4000rpm, 20min) of the recovered oral fluid. This method, however, requires the standard addition technique (1:20 dilution) because of the existence of the matrix effect. Regarding serum samples, a direct method (serum dilution) was not possible, and an SPE procedure was needed to avoid the matrix effect (use of aqueous calibration). The limits of detection and quantification when using the Salivette method were 0.035mgL-1and 0.117mgL-1, respectively; whereas, 0.015mgL-1 (LOD) and 0.050mgL-1 (LOQ) were obtained for serum. [Display omitted] •Molecularly imprinted polymer – coated Mn-ZnS QDs for cocaine recognition.•Fast cocaine and metabolites assessment in serum and oral fluid by spectrofluorimetry.•High sensitivity and selectivity of the prepared composite material and low-cost of the analytical procedure.
ISSN:0039-9140
1873-3573
DOI:10.1016/j.talanta.2018.01.017