Highly sensitive fluorescent probe and portable test strip based on polyacrylic acid functionalized quantum dots for rapid visual detection of malachite green

Malachite green (MG) has been banned in aquaculture by many countries due to its high carcinogenicity, high teratogenicity, and easy residue. However, it is cheap and efficient characteristics have made it difficult to eliminate in recent decades, so it is essential to develop a rapid and accurate detection method for MG. Here, a highly Sensitive fluorescent probe based on polyacrylic acid (PAA) functionalized CdSe/CdxZn1-xS quantum dots (QDs) was prepared for the determination of MG. QDs functionalized by PAA (QDs@PAA) were used as energy donors, and MG was used as energy acceptor to construct fluorescence resonance energy transfer (FRET) system. The fluorescence of QDs@PAA could be linearly quenched by MG in the range of 0.05 ⁓ 2 μM, and the detection limit was 0.011 μM. In addition, a small amount of QDs@PAA (30 μL) was printed on the solid substrate by inkjet printing technology to prepare fluorescent test strips. When the concentration of MG was 2 μM, the fluorescent test strips were quenched and the detection process could be completed within 10 s, demonstrating significant potential for rapid visual detection of MG.