Portable surface-enhanced Raman spectroscopy for insecticide detection using silver nanorod film fabricated by magnetron sputtering

Abstract

In order to increase agricultural productivity, several countries heavily rely on deadly insecticides, known to be toxic to most living organisms and thus significantly affect the food chain. The most obvious impact is to human beings who come into contact, or even consume, pesticide-exposed crops. This work hence focused on an alternative method for insecticide detection at trace concentration under field tests. We proposed a compact Raman spectroscopy system, which consisted of a portable Raman spectroscope, and a surface-enhanced Raman scattering (SERS) substrate, developed for the purpose of such application, on a chip. For the selected portable Raman spectroscope, a laser diode of 785 nm for excitation and a thermoelectric-cooled CCD spectrometer for detection were used. The affordable SERS substrates, with a structure of distributed silver nanorods, were however fabricated by a low-energy magnetron sputtering system. Based on an oblique-angle deposition technique, several deposition parameters, which include a deposition angle, an operating pressure and a substrate rotation, were investigated for their immediate effects on the formation of the nanorods. Trace concentration of organophosphorous chemical agents, including methyl parathion, chlorpyrifos, and malathion, adsorbed on the fabricated SERS substrates were analyzed. The obtained results indicated a sensitive detection for the trace organic analyses of the toxic chemical agents from the purposed portable SERS system.

Determination of the Limit of Detection of Multiple Pesticides Utilizing Gold Nanoparticles and Surface-Enhanced Raman Spectroscopy

“…The SERS spectra of 10 ppm of malathion is shown in Figure 3d, where the LOD is 0.1 ppm, as evidenced by the peaks that appear at 503, 628, 829, 1236, and 1392 cm −1 . 11,39,40 In Figure 3e, the SERS spectrum for 10 ppm of phosalone exhibits several peaks that are distinctly different compared to the solvent reference but only one of the peaks can be assigned on the basis of literature findings: the peak at 656 cm −1 is assigned to the PS stretch in the (RO) 2 P(S−)S moiety (R = alkyl group). 21 The LOD for phosalone is 1 ppm, which exhibits the same peak positions as the 10 ppm sample in the 300−1600 cm −1 range.…”

Rapid Detection of Acetamiprid in Foods using Surface‐Enhanced Raman Spectroscopy (SERS)

“…Recently there have been several SERS studies on pesticides. However, most of them have mainly focused on substrate development by testing simple pesticide solutions (Shende and others , ; Wong‐ek and others ; Liu and others , ), and spectral characterization (Guerrini and others ). For the applications in food matrices, many of the SERS studies still used a complex extraction procedure, which increased the analytical time (Liu and others , 2012b; Xie and others ), or achieved unsatisfactory sensitivity (Shende and others , ).…”

Applications of surface-enhanced Raman scattering (SERS) substrate

“…The SERS measurements were conducted for tree solution of organophosphate substances using a portable Raman spectrometer system [5] as described above. The SERS spectra, which related to chemical structures with P=S or p=o bonds are shown in Figure 2.…”

“…Trace detection of several toxic organophosphorous compounds [5], explosives including TNT and commercial explosives [6] and a narcotic drug based on methamphetamine [7] -at a sensitivity that can compete with, or even better than, conventional methods will be presented.…”