Malachite Green In Fish Samples Research Articles

A highly selective dual-signal response ratiometric fluorescence sensing strategy for malachite green in fish based on carbon dots/copper nanoclusters nanocomposite

Malachite green (MG), a widely used antiparasitic agent, poses health risks to human due to its genotoxic and carcinogenic properties. Herein, a stable dual-emission fluoroprobe of carbon dots/copper nanoclusters is prepared for highly selective detection of MG based on the inner filter effect. This probe exhibits characteristic emission bands at 435 and 625 nm when excited at 376 nm. After adding MG, the both emission signals were significantly quenched, and the ratio of fluorescence intensity (F435/F625) was linearly related to the concentration of MG in the range of 0.05–40 μmol L−1 with a limit of detection of 18.2 nmol L−1. Meanwhile, the two signals exhibit linear relationships with the concentration of MG, respectively, and the corresponding detection results were consistent. The fluoroprobe was successfully used for the detection of MG in fish samples with the recoveries ranging from 96.0% to 103.8% and a relative standard deviation of <3.3%.

Facile fluorescence detection of malachite green in fish using molecularly imprinted polymers doped CdTe quantum dots based system

Malachite green (MG) possesses high toxicity, therefore, the detection of MG in fish tissues is of vital importance. A novel core–shell MIPs doped CdTe quantum dots coated silica nanoparticles (CdTe-MIP/SiO2 NPs) were synthesized via a simple one-pot strategy. The materials were characterized carefully. The resulting CdTe-MIP/SiO2 NPs were coated on the thin layer chromatography plate, and coupled with miniaturized fluorimeter for fluorescence detection of MG in fish samples. The resulting CdTe-MIP/SiO2 NPs based system possessed good linearity (0.01 ∼ 20 μmol/L), high recoveries (98.36 %∼101.45 %) and low detection limit (3.7 nmol/L) for MG. Furthermore, CdTe-MIP/SiO2 NPs based system were employed to measure fish samples spiked with MG, meanwhile, HPLC was utilized to evaluate the accuracy and reliability. And the paired t-test was conducted to evaluate differences between fluorescence method and HPLC, P > 0.05 means no significant difference was observed, the results demonstrated that both fluorescence method and HPLC are suitable for MG analysis.

An ultrasensitive analytical strategy for malachite green determination in fish samples based on bright orange-emissive carbon dots

In this work, a novel fluorescence method based on an orange-emissive carbon dots (O-CNDs) was for the first time reported for the rapid and ultrasensitive determination of malachite green (MG). The O-CNDs were simply produced via a one-pot hydrothermal treatment of rhodamine B. The detection mechanism was based on the interaction between O-CNDs and MG, where the fluorescence of O-CNDs was suppressed by MG via a combined effect of inner filter effect (IFE) and dynamic suppressing. Under the optimum sensing conditions, the O-CNDs were found to display rapid reaction time (1.0 min), high selectivity and excellent sensitivity with two linear concentration ranges of 0.01–0.1 and 0.1–10.0 μmol L−1, and the corresponding detection limits were as low as 0.08 and 0.93 nmol L−1, respectively. The developed fluorescence method was successfully applied for the determination of MG in fish samples, including silver carp, blackfish, blunt-snout bream, common carp and grass carp, with satisfactory results; the recoveries were in a range of 96.0–104.8 % and the relative standard deviations (RSDs) below 4.54 %. The results of this study validated the great potential of O-CNDs as an effective fluorescence sensing agent for MG monitoring in aquatic samples.

Rapid detection of malachite green residues in fish using a surface-enhanced Raman scattering-active glass fiber paper prepared by in situ reduction method

Food safety issues, especially those related to drug residues, have caused concern in recent years. Malachite green (MG), which is frequently used as ectoparasiticide, fungicide, and antiseptic in fish farming, is poisonous and carcinogenic. Several technologies and methods have been developed to accurately detect MG, but they can be time-consuming and expensive. Herein, we prepared a glass fiber paper as a surface-enhanced Raman scattering substrate for rapid and convenient detection of MG residues in fish. Uniform silver nanoparticles were deposited on the glass fiber paper by two in situ reduction steps of silver nitrate. The Raman signal of MG was detected and recorded using a portable Raman spectrometer in 10 s. There was a good linear relationship between the surface-enhanced Raman scattering signal intensity and the concentration of MG between 1 × 10−7 and 1 × 10−5 mol/L and the limit of detection was 5 × 10−10 mol/L. Residual MG in fish samples was extracted and detected with a recovery rate range of 98.9–119.4%. This method provides a novel way to detect MG in fish.

Self-assembly PS@dual-emission ratiometric fluorescence probe coupled with core-shell structured MIP for the detection of malachite green in fish

Rapid detection of malachite green (MG) by fluorescence probes of CdTe quantum dots (QDs) coated with molecularly imprinted polymer (MIP) has been reported, but low sensitivity, slow response and narrow linear range were the main disadvantages for these MIP@QDs probes. Here, an ultra-sensitive ratiometric fluorescence probe based on self-assembly functionalized polystyrene (PS) and core-shell structured MIP was developed for the detection of MG in fish. After modified with poly(diallyldimethylammonium chloride) and hexadecyl trimethyl ammonium bromide, CdTe QDs and silica encapsulated carbon quantum dots (CDs@SiO2) with negative charges, used as detection and reference fluorophores, were respectively self-assembled on the surface of PS to form PS-QDs&CDs. And a core-shell structured MIP layer was fabricated on the surface of PS-QDs&CDs to form a ratiometric fluorescence probe of MIP@PS-QDs&CDs with sol-gel method using MG, (3-aminopropyl)triethoxy-silan and tetraethyl orthosilicate as template, functional monomer and cross-linker, respectively. With intensive fluorescence densities of QDs&CDs in nucleus, the fluorescence emission of probe at λem of 630 nm could be linearly quenched by MG, while the fluorescence emission at λem of 430 nm remained unchanged. The probe of MIP@PS-QDs&CDs owned good fluorescence stability (RSD ≤2.3%), fast response time (5 min), wide linear range (0.1–32 μmol L−1) and low detection limit (5.6 μg kg−1), and has been applied to the detection of MG in fish samples with recoveries of 94.3–110.2%. The result validated that the as-prepared probe of MIP@PS-QDs&CDs had an excellent performance for MG detection in fish samples.

Ratiometric fluorescence probe of MIPs@CdTe QDs for trace malachite green detection in fish.

A facile and practical ratiometric fluorescence probe based on two CdTe quantum dots (QDs) coated with molecularly imprinted polymers (MIPs) was prepared for the detection of trace malachite green (MG) in fish. Two CdTe QDs coated with MIPs were fabricated by a one-pot method using MG, (3-aminopropyl) triethoxysilane (APTES) and tetraethyl orthosilicate (TEOS) as template, functional monomer, and cross-linker, respectively. CdTe QDs with λem 530nm (gQDs) and 630nm (rQDs) were used as the referential fluorophore and target sensitive fluorophore, respectively. The fluorescence intensity of gQDs remained unchanged in the presence of MG, while the fluorescence of rQDs could be quantitatively quenched by MG based on the strategy of fluorescence resonance energy transfer. The ratiometric fluorescence probe (MIPs@gQDs&rQDs) was characterized by transmission electron microscopy and Fourier transform infrared spectroscopy. The linear range of MG detection was 0.1-32μmolL-1 with a detection limit of 8.8μgkg-1. The constructed probe has been successfully applied to the detection of MG in fish with the recoveries of 92.3-109.1%, which were validated by the method of HPLC. The result indicated that the probe possessed rapid response, wide linear range, high sensitivity, and relatively high selectivity, and was low-cost and easy in operation in the detection of MG in fish samples.

Detection of malachite green in fish based on magnetic fluorescent probe of CdTe QDs/nano-Fe3O4@MIPs

A magnetic fluorescent probe of CdTe QDs/nano-Fe3O4@MIPs was prepared using CdTe QDs and Fe3O4 nanoparticles as co-nucleus and molecularly imprinted polymers (MIPs) as specific recognition sites based on a reverse microemulsion method. With the specific enrichment and magnetic separation properties, the probe of CdTe QDs/nano-Fe3O4@MIPs was used to detect malachite green (MG) in fish samples. The TEM analysis showed that the particles of CdTe QDs/nano-Fe3O4@MIPs were spherical with average diameter around 53nm, and a core-shell structure was well-shaped with several Fe3O4 nanoparticles and CdTe QDs embedded in each of the microsphere. Quick separation of the probes from solutions could be realized with a magnet, indicating the excellent magnetic property of CdTe QDs/nano-Fe3O4@MIPs. The probe exhibited high specific adsorption towards MG and excellent fluorescence emission at λem 598nm. The fluorescence of CdTe QDs/nano-Fe3O4@MIPs could be linearly quenched by MG at the concentrations from 0.025 to 1.5μmolL−1. The detection limit was 0.014μmolL−1. The average recovery of spiked MG in fish samples was 105.2%. The result demonstrated that the as-prepared CdTe QDs/nano-Fe3O4@MIPs could be used as a probe to the detection of trace MG in fish samples.

Colorimetric Aptasensor for Detection of Malachite Green in Fish Sample Based on RNA and Gold Nanoparticles

A facile colorimetric aptasensor based on unmodified gold nanoparticles (AuNPs) for rapid, highly sensitive and selective detection of malachite green (MG), one of triphenylmethane dyes and antibiotics, was successfully developed. Malachite green RNA aptamer having the binding ability with high affinity and specificity would be the ideal recognition receptor for MG. RNA aptamer can adsorb on the AuNPs and protect AuNPs against salt-induced aggregation. When malachite green were added in a solution, aggregation of AuNPs was specifically induced by desorption of aptamer from the surface of gold nanoparticles as the formation of aptamer-target complex. Therefore, the salt could trigger AuNP aggregate and the solution color changed from red to blue. The solution colors and absorbance were related with the concentrations of MG, and a well linear relationship in the wide range was obtained. The detection limit of MG was down to 15.95 nM. This colorimetric method was better than other traditional methods in terms of its reduced detection time, simple signal generation, high selectivity, lower detection limit, and observation with the naked eye. The proposed one-step, label-free method was successfully used to determine MG in actual fish samples. The high recoveries of MG in fish sample detection were satisfied.

Rapid detection of malachite green in fish based on CdTe quantum dots coated with molecularly imprinted silica.

A sensitive fluorescence sensor for the detection of malachite green (MG) was fabricated by grafting molecularly imprinted polymers (MIPs) onto the surface of CdTe quantum dots (QDs). The MIP-coated QDs were synthesized via a reverse microemulsion method using (3-aminopropyl)triethoxysilane (APTES) and tetraethyl orthosilicate (TEOS) as functional monomer and cross-linker, respectively. The optimum molar ratio of MG, functional monomer and cross-linker was 1:3:10. The MIP-coated QDs exhibited uniform spheres with diameter around 49nm and excellent fluorescence emission at λex 370nm. A linear relationship with two segments between the relative fluorescence intensities and the MG concentrations ranging from 0.08 to 20μmol·L-1 could be obtained with a detection limit of 12μg·kg-1. The fluorescent probe was successfully applied to the determination of MG in fish samples with the spiked recoveries ranging from 94.3% to 109.5% which were in accordance with those of the measurement by HPLC-UV.

Mini-column assay for rapid detection of malachite green in fish

A simple, rapid and economical mini-column method for detecting malachite green (MG) residue in fish was developed. The method used a column with 2mm ID that was tightly packed with silica gel followed by alumina. Detection of MG was performed by viewing the developed mini-column at visible light by naked eye; where MG was seen as compact green band at the confluence of the silica gel layer with alumina layer. The limit of detection of the assay was 2ng which conform the minimum required performance limit (MRPL). Evaluation utility of the method indicated that all blank and spiked samples at levels below MRPL were assessed as accepted. The intensity of the green band increased whenever MG level in the extract increased; indicated that suggested mini-column technique could be used for semi-quantitative determination of MG in fish samples. The method can be used to select the questionable samples.

Application of magnetic molecularly imprinted polymers in the detection of malachite green in fish samples

Magnetic molecularly imprinted polymers (MMIPs) synthesized through suspension polymerization were used as the adsorbent for the detection of malachite green (MG) in fish samples. The morphological, thermal and magnetic properties of the MMIPs were characterized. The influence of polymerization condition on the absorption capacity of the MMIPs for MG was explored. The results gave the optimum polymerization condition as follows: using MG (0.25mmol) as template, methacrylic acid (1mmol) as monomer, ethylene dimethacrylate (5mmol) as cross linker, 2,2′-Azobis(2-methylpropionitrile) (100mg) as initiator, Fe3O4 (100mg) as magnetic nuclei, and PVA (1%) as dispersant. Under the optimum condition the apparent maximum adsorption capacity of MMIPs is 5693μg·g−1 with dissociation constant being 23.5mg·L−1. The MMIPs also have strong magnetic responses to an external magnet, which enable the rapid separation from the sample solution. The MMIPs were employed for the detection of MG residue in fish samples combined with HPLC. The recoveries of spiked MG in fish samples ranged from 82.7% to 111% with RSD in the range of 2.0%–12.8%. The MMIPs can retain 90% of the original adsorption capacity even if used for 5 times. Thus, the prepared MMIPs can be applied to the sample pretreatment for separation and enrichment of MG residue in fish samples.

Electrochemical determination of malachite green at graphene quantum dots–gold nanoparticles multilayers–modified glassy carbon electrode

A graphene quantum dots–gold nanoparticles–modified glassy carbon electrode was used to investigate the electrochemical behaviors of malachite green (MG). Cyclic voltammetry curves of MG at the modified electrode exhibited a pair of quasi-reversible adsorption-controlled redox peaks at 0.502 V (E pa) and 0.446 V (E pc) in a 0.05 mol L−1 H2SO4 solution. Under the optimal conditions, by using differential pulse voltammetry as the detection method, a linear relationship was obtained between the oxidation peak current and the MG concentration in the range of 4.0 × 10−7 to 1.0 × 10−5 mol L−1 with the detection limit as 1.0 × 10−7 mol L−1 (signal-to-noise ratio of 3). The modified electrode was applied in the determination of MG in fish samples, and the results were satisfactory with recoveries from 96.25 to 98.00 %. Furthermore, the modified electrode showed very good reproducibility and stability.

Electrochemical determination of malachite green using a multi-wall carbon nanotube modified glassy carbon electrode

A multi-wall carbon nanotube (MWNT) film-modified electrode is described for the determination of malachite green (MG). The electrochemical profile of MG was examined using cyclic voltammetry (CV) and differential pulse voltammetry (DPV), suggesting that the MWNT film facilitates the electron transfer of MG in terms of a potential shift and then significantly enhances the oxidation peak current of MG. The experimental parameters, such as supporting electrolyte, thickness of MWNT film, scan rate and accumulation time, were optimized. Consequently, a sensitive and convenient electrochemical method is proposed for the determination of MG. The oxidation peak current is proportional to the concentration of MG over the range from 5.0 × 10−8 to 8.0 × 10−6 mol L−1 obeying the following equation: ip = 0.09 + 1.19 × 107 C (r = 0.995, ip in µA, C in mol L−1). The detection limit is 6.0 × 10−9 mol L−1 (signal to noise = 3) after 5 min of accumulation. Moreover, this method possesses good reproducibility (RSD is 5.6%, n = 8) as well as long-term stability. Finally, the new method was employed to determine MG in fish samples.