Electrochemiluminescent properties of CdTe quantum dots in different potential ranges and their application to the ultra-sensitive detection of phenylephrine hydrochloride and paliperidone

Abstract

CdTe quantum dots (CdTe QDs) were synthesized using mercaptopropionic acid (MPA) as a stabilizer. The electrochemiluminescence (ECL) mechanism of CdTe QDs was examined at cathodic (−2.1 to 0 V) and anodic (0–1.5 V) potentials. Utilizing dissolved oxygen as a co-reactant for cathodic CdTe QDs, the addition of phenylephrine hydrochloride (PEH) triggers a burst effect on the intermediate OH at the electrode surface, resulting in a reduction of electron hole formation. Consequently, a novel method for detecting PEH in the concentration range of 0.2–10 μM has been developed. A strong linear correlation was observed between LgC_PEH and the ECL intensity ratio (I/I₀) of cathodic CdTe QDs, with a detection limit of 37 nM. Tri-n-propylamine (TPrA) was utilized as a co-reactant for the anode of CdTe QDs. The addition of paliperidone (PP) occupies the oxidized vacancies of TPrA, leading to a diminished ECL signal. A new method was subsequently established to detect PP in the concentration range of 0.2 nM–1.0 μM with a detection limit of 18 pM. This method has been successfully applied to detect PEH in urine and in compound tropicamide eye drops, as well as to quantify PP content in paliperidone sustained-release tablets and serum, demonstrating excellent recovery and selectivity.