A novel approach to determine leucomalachite green and malachite green in fish fillets with surface‐enhanced Raman spectroscopy (SERS) and multivariate analyses

Abstract

The use of illegal fish drugs, such as malachite green (MG) in aquaculture has raised growing concerns over the safety of aquatic food products, and sensitive and rapid methods for detection of these drugs in fish muscle are much needed. Simplified extraction methods coupled with surface‐enhanced Raman spectroscopy were used for analysis of MG and its metabolite leucomalachite green (LMG) in tilapia fillets containing 0–50 ng g−1 LMG or MG. Principal component analysis and partial least squares (PLS) regression were used for spectral data analyses. High sensitivity (MG or LMG could be detected at 1–2 ng g−1 levels) and PLS models with good predictability [root mean square error of validation (RMSEV) = 1.97–2.21 ng g−1, R2 = 0.984–0.988] were possible with suitable sample extraction methods. The simplest extraction method developed provided an RMSEV of 9.32 ng g−1 and R2 of 0.788, and although this was not ideal, detection of MG and LMG at 5 ng g−1 level with this method could reduce sample throughput time and provide for faster detection of LMG and MG. Copyright © 2012 John Wiley & Sons, Ltd.

Detection of Prohibited Fish Drugs Using Silver Nanowires as Substrate for Surface-Enhanced Raman Scattering

“…Particularly for MG, it was the number one illegal drug found in fish and fish products in the past ten years, based upon the database of the Rapid Alert System for Food and Feed of European Union [30]. In our previous study, we were able to detect MG and CV at concentrations as low as 0.1 ng/mL using Au–Ag core–shell (Au@Ag) bimetallic nanoparticles [31], which is much more sensitive than that using two commercial SERS substrates and as-obtained Au nanospheres [18,19,20,21,22]. However, because of the effect of sample matrices, the sensitivity for the detection of MG in actual fish muscle could be decreased by as much as 20 times compared to that in standard solutions [22].…”

“…A 20× microscope objective and 5 mW laser power were used for the acquisition of the normal Raman and SERS spectra (400–2000 cm −1 ). The selection of a 633 nm laser source was based upon the results of our previous studies on CV and MG [19,21,31]. The maximum absorption wavelength of CV (590 nm) and MG (620 nm) are close to the 633 nm laser excitation wavelength, leading to strong resonance enhancement and an overall high enhancement factor [22,31].…”

“…SERS methods could be sensitive, easy-to-use, and affordable, serving as a good alternative to the more complicated and expensive chromatographic method. Our group’s previous studies involving the use of commercial SERS substrates and lab-synthesized Au nanospheres as SERS substrates led to less ideal results in sensitivity: the lowest detectible concentrations for standard solutions were 0.5–700 ppb for MG, 0.5–50 ppb for CV, and 0.8–5 ppm for furazolidone [18,19,20,21,22]. This study is a continuation of our previous work on the development of more sensitive SERS approaches for the detection of banned fish drugs.…”

Permethylated-β-Cyclodextrin Capped CdTe Quantum Dot and its Sensitive Fluorescence Analysis of Malachite Green

“…The commercial use of MG is not permitted in the UE since 2002 and a minimum required performance limit (MRPL) at 2 μg·kg −1 has been established for the determination of MG residues in aquaculture products. The determination of residual MG in environmental water samples or fish had been carried out by liquid chromatography [18,19] coupled to several detectors such as fluorescence detection and mass spectroscopy [20].…”

“Zero-transfer” production of large-scale, flexible nanostructured film at water surface for surface enhancement Raman spectroscopy

“…As shown in Figure 3(a), the NBA characteristic peak at 593 cm À1 can be clearly identified, down to low concentration of 1 Â 10 À10 M. We further explored the prepared SERS substrate as a pesticide sensor as shown in Figure 3(b), where our Ag coated elastomer film is efficient for the detection of malachite green (MG) at 2.7 Â 10 À7 M, which is illegal to exist in fishery aqueous environments. 41 For the RSD test, 5 ll of 1 Â 10 À7 M NBA aqueous solution was dropped onto the film surface and results for 10 measurement spots as randomly selected are shown in Figure 4. The RSD was calculated as 9.7% for NBA characteristic peak, indicating a good reproducibility of our prepared SERS substrate.…”