Jellylike flexible nanocellulose SERS substrate for rapid in-situ non-invasive pesticide detection in fruits/vegetables

This study aimed to develop a jellylike flexible substrate based on nanocellulose decorated with Ag nanoparticles (Ag/NC substrate) and explore its applications for rapid in-situ pesticide detections in fruits and vegetables by surface-enhanced Raman spectroscopy (SERS). The performances of Ag/NC substrate were characterized by rhodamine 6G (R6G). The limit of detection recorded by a portable Raman spectrometer is 10(-8) M. The substrate still exhibited satisfactory sensitivity after 60-day preservation. Jellylike and slightly sticky Ag/NC substrate demonstrated good adaptabilities in attaching to sample surfaces and is suitable for in-situ SERS detection. Two types of pesticides on apple peels and cabbages were detected by rapid in-situ and non-invasive SERS method coupled with Ag/NC substrate. The lowest detectable level was 0.5 ng/cm(2) for thiram and 5 ng/cm(2) for thiabendazole, which were well below the maximum residue levels. These results demonstrate that Ag/NC substrate is sensitive for rapid in-situ multi-pesticide detection in food.