Optical detection of scopolamine and ketamine with a BODIPY-Phen conjugate and Cu(II)

Abstract

Chemical submission is becoming a global growing threat. Therefore, the development of fast and reliable methods for detecting the presence of chemical submission drugs in drinks is of great interest. For this purpose, a new BODIPY-Phen conjugate consisting of a 1,10-phenanthroline moiety connected through its 4-position to the meso position of a BODIPY dye has been synthesized and characterized by NMR, UV–vis spectroscopy and by single-crystal X-ray diffraction. BODIPY-Phen in combination with Cu(II) was used as a probe for the fluorescent and colorimetric detection of scopolamine and ketamine, two of the drugs used in cases of chemical submission. The determined limits of detection in water were 3 μM for scopolamine and 2.88 μM for ketamine. Selectivity of the probe in the presence of other drugs and some possible interferents that could be found in beverages has also been tested. The detection process seems to be due to a reduction of the Cu(II) ion to Cu(I) followed by coordination of Cu(I) to the BODIPY-Phen conjugate, which results in quenching of its fluorescence together with a visible color change. The probe is able to detect by the unaided eye the presence of scopolamine in real soft drinks and alcoholic beverages spiked with the drug.