A “drop‐wipe‐test” SERS method for rapid detection of pesticide residues in fruits

Abstract

A simple “drop‐wipe‐test” approach for rapid detection of pesticide residues in fruits was developed based on surface‐enhanced Raman spectroscopy (SERS) coupled with wiper‐type filter paper substrate. The filter paper was coated with silver nanoparticles (Ag NPs) and used as a flexible and absorbent wiper‐type SERS substrate. The first two steps “drop” and “wipe” were combined to simplify the procedures of extraction and sampling of the analyte molecules. “Test” was the last step to obtain the spectral data using a portable Raman spectrometer (Hx‐Spec) developed by our laboratory. The entire detection process was completed just in a few minutes. The optimal wipe time of ~15 s was confirmed used to ensure a thorough extraction of analyte molecules. The as‐prepared SERS substrate was used for rapid detection of pesticide residue (i.e., thiram) in apple, pear, and grape by “drop‐wipe‐test” method. Results demonstrate that the concentrations of thiram spiked on the three fruits skin show a linearly relationship with the average intensity (n = 7) of SERS spectra with R‐square values of 0.9991, 0.9872, and 0.9841, respectively. The limit of detection of thiram in apple, pear, and grape peel was 4.6261, 5.1799, and 5.7061 ng/cm2, respectively. The detection limits are all below the maximum residue limits for pesticide in food that were set by the National Food Safety Standard of China (GB). The results demonstrate that SERS method coupled with a flexible and absorbent SERS substrate can be used as a practical application for a reliable, rapid, and sensitive detection of pesticide residues.

Recent advances in linear and nonlinear Raman spectroscopy. Part XIII

“…Wang et al described a "drop‐wipe‐test" SERS method for the rapid detection of pesticide residues in fruits. The results demonstrate that SERS coupled with a flexible and absorbent SERS substrate can be used as a practical application for the reliable, rapid, and sensitive detection of pesticide residues . Wang and co‐workers described the on‐site detection of succinylcholine, a depolarizing neuromuscular blocking agent to relax muscles, in a biomedical matrix by SERS for the first time .…”

SERS detection of food contaminants by means of portable Raman instruments

“…Wang et al used a flexible SERS substrate, produced by immersing filter paper in a solution of colloidal Ag NPs, to detect the presence of thiram on the peel of fruits that had been spiked with the pesticide. The analyte was collected by simply wiping the substrate on the fruit peel.…”

Rapid Quantitative Detection of Deltamethrin in Corydalis yanhusuo by SERS Coupled with Multi-Walled Carbon Nanotubes

“…Huang et al (2015) combined SERS technology with a rapid pretreatment quick, easy, cheap, effective, rugged and safe (QuEChERS) method to detect chlorpyrifos pesticide residues in rice, and the limit of detection of chlorpyrifos in rice was less than 0.506 mg L −1 [ 20 ]. Wang et al (2017) developed a flexible and absorbent wiping SERS substrate, which is used to quickly detect thiram residues in apples, pears and grapes [ 21 ]. Zhai et al (2017) used SERS for the determination of acetamiprid, chlorpyrifos and carbendazim mixed pesticides in apple samples, which provides an ultra-sensitive SERS performance for the simultaneous quantification of multiple residual pesticides in apple samples [ 22 ].…”