Development of cellulose Nanofiber-based substrates for rapid detection of ferbam in kale by Surface-enhanced Raman spectroscopy

This study developed a novel surface-enhanced Raman spectroscopy (SERS) method coupled with cellulose nanofiber (CNF)-based SERS wipers that were fabricated on quartz papers coated with a mixture of silver nanoparticle (AgNP) and gold nanostar (AuNS). A drop-wipe-test protocol was developed for rapid detection of pesticide residues in vegetables by SERS. Tremendously enhanced Raman scattering signals were obtained from the quartz/CNF/mixture (AgNP + AuNS) substrate, which were much higher than the paper/mixture (AgNP + AuNS) substrate. This method was used to detect ferbam on kale leaves within a few minutes and the detection limit was 50 mu g/kg based on the PLS models (R-2 = 0.89). The enhancement factor of the SERS substrate was calculated to be similar to 10(4) with satisfactory reproducibility. Satisfactory SERS performance could be achieved within 1-month storage period. These results demonstrate that this CNF-based SERS/wiper method is a practical approach for rapid detection of chemical contaminants in fresh produce.

Automated summary

A novel SERS method coupled with CNF-based wipers was developed for rapid detection of pesticide residues in vegetables. The method showed satisfactory performance in detecting ferbam within a few minutes with a detection limit of 50 μg/kg. The enhancement factor of the SERS substrate was calculated to be around 10^4 with satisfactory reproducibility.