In 2026, Analytica Chimica Acta published the work of Prof. Fei Junjie's group (first author: Huang Linzi; corresponding authors: Fei Junjie and Zhao Pengcheng; DOI: 10.1016/j.aca.2026.345715) on the first photoelectrochemical (PEC) sensor for the food additive carmine (CRM).
Carmine is a natural red colorant widely added to baked goods, beverages, meat and dairy products, jams and candy. Although generally considered safe within regulatory limits, excessive intake may cause allergic reactions, asthma, gastrointestinal disorders and ADHD-like symptoms in children, so sensitive detection matters for food safety.
CuO is a narrow-band-gap p-type semiconductor with strong visible-light absorption and an ideal partner for n-type Sb2WO6. The internal electric field (IEF) formed at the heterojunction interface promotes charge separation and suppresses recombination. Density functional theory calculations directly confirmed the interfacial interaction between the two components.
The sensing mechanism relies on the specific adsorption and electrostatic interaction between CRM molecules and the CuO surface: CRM passivates surface active sites and blocks hole transfer, producing a characteristic photocurrent suppression. The sensor achieves high-sensitivity CRM detection under conventional UV-Vis excitation with good selectivity and stability.
Photoelectrochemical measurements used the Perfectlight PLS-FX300HU High-Homogeneity Integrated Xenon Lamp, which delivers a continuously tunable 10x10 to 50x50 mm2 rectangular uniform light spot and reaches Class-A solar-simulator uniformity for areas up to 20x20 mm2.
Read the Chinese report: ACA: Sb2WO6/CuO PEC sensor.
