A strong electrochemiluminescence (ECL) of palmatine in NaOH medium was observed at a vaseline-impregnated graphite anode. The ECL production could be described as follows: hydroxyl radical (OH(•)) was generated via the oxidation of hydroxyl group (OH(-)) in NaOH medium, and the formed OH(•) subsequently oxidized palmatine base converted from palmatine in NaOH medium to the excited state oxypalmatine (oxypalmatine*). As the oxypalmatine* went back to its ground state, a stronger chemiluminescence was produced. Based on the ECL of palmatine, an ECL method for the determination of palmatine was proposed. An ECL signal of palmatine in NaOH solution was obtained by applying direct current of 15 mA to the vaseline-impregnated graphite anode. The ECL intensity was rectilinear with palmatine concentration in the range of 8.0 × 10(-7) to 2.0 × 10(-5) mol l(-1) and the limit of detection (signal-to-noise = 3) was 3 × 10(-7) mol l(-1) . The proposed method was applied to the determination of palmatine in pharmaceutical preparations.

Fluorescent carbon nanodots (CNDs) capable of dual emission blue and red light (B-R-CNDs) (460 and 610 nm) have been synthesized by a simple and low cost electrochemical method of discharging indole dissolved in ethanol in the presence of alkali. The presence of alkali played an important role to achieve switching from single blue emission to dual emission (red and blue). The as-synthesized CNDs have been thoroughly characterized by different spectroscopic techniques. Moreover, the origin of the red emission has been investigated by analyzing the intermediate product of CNDs using gas chromatography−mass spectrometry. It was found that 2naphthaleneamine, an intermediate product of B-R-CNDs, achieves an extended π-conjugated system and heteroatom functional groups to B-R-CNDs, which are synergistically responsible for emission at longer wavelength. Moreover, the alkaliethanol system played a pivotal role in structural transition from single emission to dual emission, because surface oxidation is caused by hydroxyl radicals produced in the alkaline system. Surface oxidation creates surface defects thereby giving rise to the surface-state-related red emission. The red emission of B-R-CNDs are found highly pH dependent which makes them a potential candidate for application in pH sensing. Moreover, as-prepared B-R-CNDs have been used in full color bioimaging of HepG2 cells and exhibit an accurate mitochondrial-targeting ability.

A novel electrochemiluminescence (ECL) luminophor of amoxicillin was studied and found to generate ECL following the oxidation or reduction of amoxicillin. The amoxicillin oxidation state was also found to eliminate the reduction state, generating ECL. When solutions of amoxicillin were scanned between +1.5 V and -1.0 V with a graphite electrode in the presence of cetyltrimethyl ammonium bromide using KC1 as the supporting electrolyte, ECL emissions were observed at potentials of -0.7 V and +0.5 V. The ECL intensity at -0.7 V was enhanced by HO. Based on these findings, an ECL method for the determination of the amoxicillin concentration is proposed. The ECL intensities were linear with amoxicillin concentrations in the range of 1.8 × 10 g/mL to 2.5 × 10 g/mL, and the limit of detection (signal/noise = 3) was 5 × 10 g/mL. The florescence of amoxicillin had the greatest emission intensity in a neutral medium, with the emission wavelength dependent on the excitation wavelength. The experiments on the ECL mechanism for amoxicillin found that the electrochemical oxidation products of dissolved oxygen and active oxygen species contributed to the ECL process. The data also suggest that the hydroxyl group of amoxicillin contributed to its ECL emission.

A novel mechanically durable superhydrophobic material is prepared from kaolin by mimicking the lotus leaf's ability of self-repairing micro-structures and regenerating hydrophobic wax layer.