<p>➀ Researchers have developed a novel caffeine sensor using zinc-doped tin oxide nanoparticles as an electrocatalyst.</p><p>➁ The sensor exhibits exceptional sensitivity and selectivity, with potential applications in food safety, healthcare, and environmental monitoring.</p><p>➂ The sensor is based on Zn-SnO₂ nanoparticles, which are coated onto a gold electrode and show high sensitivity and selectivity in detecting caffeine.</p>