Discriminative detection of morphine and methamphetamine-like street samples by label-free Cu doped-silver nanoparticles chemosensor

This research provides a straightforward and sensitive method for detecting morphine (MOR) and methamphetamine (MET) by colorimetry. In order to characterize the nanoprobe as it was prepared, XRD, FT-IR, XPS, UV–vis, TEM, ICP, DLS, and EDS analyses were conducted. We evaluated the performance of Ag/Cu nanoparticles for colorimetric sensing of MOR and MET. As well as naked-eye detection (photographs), UV–visible spectroscopy was used to monitor and record the results. Color shifts of colloidal NP solutions or surface plasmon resonance (SPR) absorbance bands were used to differentiate between MOR and MET, leading to the discovery that NP could distinguish between the two. Based on the linearity of the calibration curves' ranges, MOR and MET were found to have different limits of detection (LODs), which are 0.21 µg/mL and 0.49 µg/mL for each, respectively. In addition, they displayed a linear range of 0–50 µg/mL and 0–100 µg/mL, for MOR and MET, respectively. When Ag/Cu NPs are exposed to MOR and MET, they aggregate and exhibit noticeable color changes. For MOR, the changes ranged from bright yellow to smoky, while for MET, they were dark orange. The optimal incubation time for sensing MOR and MET was 7 and 35 min, respectively.