Facile method for detecting C23H25ClN2 in fish using Au nanoparticle films as SERS substrates on glass

Malachite green (C 23 H 25 ClN 2 ) is an illegal fungicide of aquatic products due to its potential carcinogenic, teratogenic, and mutagenic effects. It is typically challenging to detect C 23 H 25 ClN 2 in fish with conventional techniques. The study reported a simple and rapid method for detecting C 23 H 25 ClN 2 on fish surface with surface-enhanced Raman scattering (SERS). Using the seed growth method with trometamol as the modifier, 110 nm in-diameter gold nanoparticles on thin glass as SERS substrate were prepared, which exhibited high SERS activity, reproducibility, stability, and flexibility in SERS measurement. The fish samples required no pretreatment and the entire measurement took <5 min. Quantitative analyses were also conducted. Excellent linear relationships ( R 2 = 0.9397–0.9977) were obtained between the concentrations and the peak intensities of C 23 H 25 ClN 2 at some characteristic peaks with a wide concentrations range (0.5–10 μM). The detection limit can reach 0.5 μM. This method provided an easy and fast way to detect C 23 H 25 ClN 2 on fish surface for food safety.