Determination of Morphine

What is it about?

A simple and selective method was described for the rapid determination of morphine based on its extraction and preconcentration by molecularly imprinted polymers (MIPs) on multi-walled carbon nanotubes (MWCNTs) prior to its chemiluminometric recognition. MIP–MWCNTs composite was obtained by copolymerization of certain monomers on the surface of vinyl modified MWCNTs using morphine as template molecule. Dispersed MIP–MWCNTs indicated good tendency and selectivity to low amounts of morphine in relatively acidic condition. Some important factors containing buffer and its pH, ionic buffer, incubation time, eluent, etc., were optimized for extraction step. KMnO4–carbon dots (C-dots) chemiluminescence (CL) reaction was applied as recognition device for extracted morphine. Morphine can linearly quench the CL emission of this system via its interaction with C-dots. The calibration graph was obtained in the range of 0.003–1.2 mg L 1 morphine concentration with a detection limit (3 s) of 0.82 mg L 1. The relative standard deviation (RSD%) for five determinations of 0.01, 0.1, and 0.8 mg L 1 morphine were 1.11%, 2.54% and 1.98%, respectively. The developed method has acceptable features in comparison with other reported methods and was satisfactorily applied to the accurate determination of morphine in pharmaceutical and urine samples.

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Why is it important?

A molecular imprinted polymer on the surface of multi-walled carbon nanotubes was generated via selective polymerization of vinyl functional groups. Morphine was applied as template molecule. The produced composite of MIP–MWCNTs was exploited as suitable absorbent to the effective extraction of low quantities of morphine using dispersive solid phase extraction technique followed by elution by alkali ethanol. The offered extraction method showed high selectivity and efficiency. The extracted morphine was determined by using simple and inex- pensive chemiluminescence method based on quenching effect of morphine on the CL emission produced by direct reaction of carbon dots and KMnO4. The developed method was applied to the quantication of morphine in pharmaceutical and human urine samples with good agreement to the standard method.

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