Malachite Green Residues Research Articles

Magnetic covalent organic framework as an absorbent coupled with a portable mass spectrometer for rapid detection of malachite green and its metabolite residues

It is important to develop specific adsorbents for malachite green and other fish drug residues. Herein, a simple strategy for synthesizing a novel magnetic covalent organic frameworks (rFe3O4@Py-COF) has been studied, and the materials were used as a magnetic absorbent for solid phase extraction (MSPE) of malachite green (MG) and its metabolite as leucomalachite green (LMG) in fishes. In this study, the mild reduction program of formic acid replacing traditional sodium borohydride as a reducing agent has been adopted to increase the stability of the framework, which can maintain the original high crystallinity and surface area of the reduced COF. The secondary amine bond is expected to be used as the reaction center for further functionalization of COF pore wall. Subsequently, rFe3O4@Py-COF (rmCOF) obtained after reduction was used as MSPE materials to detect MG and LMG by a portable mass spectrometer. After optimizing the conditions, the linearity is good within the range of 1.25∼100 μg/kg (R2≥0.9954), the limits of detection (LODs) are 0.31∼0.44 μg/kg with satisfactory recovery (85.0 %∼106.0 %). These results indicate that the assay is suitable for monitoring MG and LMG in complex aquatic foods, providing protection for food safety.

Dual-color immunochromatographic test strip for simultaneous sensitive detection of malachite green and leucomalachite green residues in fish and shrimp meat samples

A sensitive dual immunochromatographic test strip (dual-ICTS) was developed to detect malachite green (MG) and its metabolite, leucomalachite green (LMG), using two types of gold nanoparticles: round-shaped (red) and star-shaped (blue). The detection limits were determined to be 0.221 μg L−1 for MG and 0.214 μg L−1 for LMG, respectively. The dual-ICTS provided a cut-off value of 1.8 μg L−1 for MG and LMG detection. The dual-ICTS successfully detected MG and LMG in food samples, with recovery rates ranging from 86 % to 116 %. The dual-ICTS was evaluated by correlation analysis between the proposed assay and the well-established enzyme-linked immunosorbent assay in the MG and LMG detection. This is the first report on the development of the ICTS that can detect both MG and LMG at the same time within only 5 min, making it a sensitive and rapid tool for on-site detection.

HAuCl4/K4Fe(CN)6 reaction mediated silver nanosol as SERS substrate for robust detection of malachite green residue in seafood

Irreproducibility is considered as a significant obstacle to the widespread use of surface enhanced Raman spectroscopy (SERS) as a sensing platform. However, in terms of the SERS performance in applications, less attention has been paid on the stability, i.e., repeatability and reproducibility compared to sensitivity. Here, based on HAuCl4/K4Fe(CN)6 reaction and silver nanosol (Ag NS), a reaction mediated SERS (R-SERS) platform was proposed for the detection of malachite green residue (MG) in aquatic products, aiming to improve both the sensitivity and stability of SERS. Wherein, the HAuCl4/K4Fe(CN)6 reaction produced Au0 grows on Ag NPs and provided additional “hot spots” to enhance signal intensity. Meanwhile, the reaction system released cyano group (-C≡N) will cap on the surface of Ag or Au NPs and act as an internal signal at ∼2100 cm−1 to adjust the background signal. As a proof of principle, adenine (Ade, 730 cm−1), ceftriaxone (Cef, 1345 cm−1) and MG (1170 cm−1) were selected as targets to discuss the detection performance, with linear ranges of 0.1 ∼ 20 μM, 0.1 ∼ 10 μM and 0.1 ∼ 2 μM and limit of detection (LOD, 3σ/M) of 0.079 μM, 0.050 μM and 0.032 μM, respectively. In practical applications, MG residue in aquatic products were detected with the recoveries ranged from 85 % to 98 % and the coefficient of variations of intra-assay below 6.6 %. The R-SERS platform, therefore, was demonstrated to enhance SERS intensity and stability with in situ growth of label on Ag NPs, suggesting its potential applications in SERS sensing.

Evaluating the persistence of malachite green residues in tilapia and pacu fish

Although banned in food-producing animals, residues of malachite green (MG) and its primary metabolite, leucomalachite green (LMG), have been found in fish due to illegal use in aquaculture and the release of industrial wastewater, which represent a serious risk to food and environmental securities. This study aimed to investigate the residue depletion profile of MG and LMG in edible tissues of Nile tilapia (Oreochromis niloticus) and pacu (Piaractus mesopotamicus) cultured simultaneously under the same environmental conditions to support control measures in case of abuse. An analytical method involving QuEChERS sample preparation and liquid chromatography coupled to tandem mass spectrometry was developed, validated, and applied to quantify MG and LMG residues in fish fillets from two depletion experiments after treatment by immersion bath (MG at 0.10 mg L-1 for 60 min). During the experiment, the average water temperature was 30 ºC, while the pH was 6.9. The method is selective, precise (CV = 0.4 - 22%) and accurate (recovery 92 - 114%). The limits of detection and quantification are 0.15 and 0.5 ng g-1, respectively. In both species, the sum of MG and LMG residues were quantified up to the 32nd day post-exposure, and the concentrations were significantly higher in the pacu fillets (up to 3284 ng g-1) than in Nile tilapia (up to 432 ng g-1). The sums of MG and LMG residues were below 2 ng g-1 at 44 days and 342 days for Nile tilapia and pacu, respectively – the Minimum Required Performance Limit (MRPL) for analytical methods intended to monitor forbidden substances in food according to old European Commission guidelines. The persistence of MG residues in pacu may be attributed to its higher lipid content, which favors the accumulation of the non-polar metabolite LMG. These results provide insights into the concern about human, animal, and environmental health risks resulting from unauthorized use or aquatic contamination by industrial wastewater containing MG residues.

Ag microlabyrinth/nanoparticles coated large-area thin PDMS films as flexible and transparent SERS substrates for in situ detection

Flexible and transparent surface-enhanced Raman scattering (SERS) substrates haveattractedmuchattention as a fast, sensitive and in situ detection platform for practical applications. However, the large-area fabrication of flexible and transparent SERS substrates with high performance is still challenging. Here, a flexible and transparent SERS substrate based on large-area thin PDMS film decorated with Ag microlabyrinth/nanoparticles hierarchical structures (denoted as ALNHS@PDMS) is fabricated by using the floating-on-water method and magnetron sputtering technology. By optimizing the sputtering time, the ALNHS with multiple hot spots are uniformly distributed on the PDMS surface. Based on characterizing the rhodamine 6G (R6G) with a portable Raman spectrometer, the optimal ALNHS@PDMS film exhibits a high enhancement factor (5.2 × 106), excellent uniformity and reproducibility, as well as superior mechanical stability. In addition, thanks to the good sticky feature and bi-directional activation property of the thin ALNHS@PDMS film, the prepared flexible and transparent SERS substrate can achieve in situ detection of malachite green residues (10-6 M) on apple and tomato skins. This large-area, thin, mechanically robust, flexible and transparent ALNHS@PDMS film, integrated with a portable Raman spectrometer, shows great potential for point-of-care testing (POCT)in practical applications.

Strategies for Solving the Issue of Malachite Green Residues in Aquatic Products: A Review

Malachite green (MG) residue in aquatic products is a widely concerning issue, and the possible source of MG contamination includes its illegal usage and environmental pollution. A variety of strategies for solving such a problem have been proposed, and the research about them is summarized in this review. The MG contamination in aquaculture environments can be eliminated by adsorption, degraded by advanced oxidation processes (AOPs), or biodegraded by microbes or enzymes. The illegal usage of MG can be prevented by screening novel anti-Saprolegnia sp. agents from current available agricultural antibiotics, plant extracts, or antagonistic microbes. Nevertheless, deficiencies also existed in these proposed solving strategies. Therefore, further research opportunities in such areas were provided. This includes developing effective combinatorial methods (adsorption + AOPs or biodegradation) for eliminating MG from the aquaculture environment; systematically considering the impact of practical conditions on the efficiency of MG elimination; screening more efficient anti-Saprolegnia sp. agents; and systematically evaluating both the in vivo activities and safety of these agents.

Au nanoparticles decorated covalent organic framework composite for SERS analyses of malachite green and thiram residues in foods

A three-dimensional (3D) surface-enhanced Raman scattering (SERS) substrate composed of gold nanoparticles (AuNPs) self-assembled covalent organic frameworks (COFs) was fabricated via the electrostatic interaction between positively charged COFs and negatively charged AuNPs, which exhibited excellent SERS performance and were successfully applied for the analyses of malachite green (MG) residue in different seafood products as well as thiram residue in several kinds of fruit juice. The raspberry-like structure SERS substrate has a larger surface area that can provide more adsorption sites in testing and improve the efficiency of sample enrichment. By using this developed SERS substrate, the detection linearity ranges are 1.0 × 10−9 mol·L−1–1.0 × 10−6 mol·L−1 for MG and 5.0 × 10−8 mol·L−1–1.0 × 10−5 mol·L−1 for thiram (R2 ≥ 0.995). The detection limits are 6.2 × 10−10 mol·L−1 for MG and 1.7 × 10−8 mol·L−1 for thiram, respectively. The COF-AuNPs substrate was actually applied for analysis of MG in seafood products and thiram in different fruit juice, with the recoveries in the ranges of 94.67–108.99 % for MG and 95.00–107.58 % for thiram, and both of the relative standard deviation (RSD) are no more than 5.88 %. This work indicates that the developed COF-AuNPs substrate is promising for SERS analyses and detections of residues in foods.

Quantitative Evaluation of Malachite Green Residues in Fish and Their Cooking Impact

Quantitative Evaluation of Malachite Green Residues in Fish and Their Cooking Impact

Removing Malachite Green and Leucomalachite Green From Freshwater and Seawater With Four Water Treatment Agents

Malachite green (MG) residue in aquatic environments can adversely affect food chains. To solve this problem, many adsorbents have been developed to remove MG from aqueous solutions. These adsorbents exhibit benefits in different aspects such as low cost, nontoxicity, and environment friendliness. Zeolite, oyster shell powder (OSP), humic acid (HA), and Chloride dioxide (ClO2) are widely used agents for water purification, indicating their potential to remove MG from both freshwater and seawater. Liquid chromatography tandem mass spectrometry was performed as a valid analytical method for measuring MG and its metabolite leucomalachite green (LMG). The analysis examined linearity, specificity, accuracy, precision, and limit of quantification. We found that three agents—zeolite, OSP, and HA—have high affinity for MG and LMG in both freshwater and seawater because of their physicochemical properties; ClO2 exhibited even greater efficiency for MG and LMG degradation due to its oxidation capacity. The MG removal efficiency of zeolite, OSP and HA in freshwater was 100%, 87.52%, and 100%, respectively. In the MG-containing seawater, the removal efficiency of zeolite, OSP and HA was 95.24%, 6.57%, and 89.36%, respectively. The LMG removal efficiency of zeolite, OSP and HA in freshwater was 100%, 53.56%, and 100%, while in seawater, the LMG removal efficiency of zeolite, OSP and HA was 100%, 62.70%, and 84.65%, respectively. ClO2 treatments in both freshwater and seawater expressed 100% removal efficiency. The adsorption capacity of three water agents in MG-containing freshwater decreased in the order: zeolite = HA > OSP; in MG-containing seawater: zeolite > HA > OSP. Whereas the adsorption capacity of three water agents in LMG-containing freshwater decreased in the order: zeolite = HA > OSP; in LMG-containing seawater: zeolite > HA > OSP. In this study, four water treatment agents are reported to remove MG and LMG from freshwater and seawater, indicating their potential for reducing the amount of hazardous MG and LMG residue in aquatic environments.

Rapid and flexible construction of inverted silicon architectures with nanogaps as high-performance SERS substrates

Three-dimensional (3D) plasmonic nanostructures act as excellent surface-enhanced Raman spectroscopy (SERS) substrates for detecting trace analytes. Nevertheless, an efficient 3D architecture and the optimal fabrication route remain to be uncovered to further raise the performance of 3D SERS substrates and expand application horizons. This work reports a cost-effective and flexible route to fabricate 3D inverted silicon (Si) architectures with nanogaps that are difficult to achieve by conventional lithography towards SERS applications. Finite-difference time-domain simulations demonstrated that the distribution of electrical field depended significantly on the architecture and layout of inverted pyramids. Several parameters including volume ratio of HF/HNO3 mixtures, indentation force and etching time were evaluated to determine optimal fabrication process of inverted Si architecture. Based on an electrochemical dissolution model and molecular dynamic simulations, the rapid selective etching can be ascribed to nanocrystals in amorphous Si (a-Si) regions, and distorted Si beneath a-Si layer. SERS detection illustrated an impressive sensitivity and excellent reproducibility, and the practical applicability of as-prepared SERS substrates was demonstrated by detecting malachite green residues from different water environments as well as fish tissues and scales. The proposed selective etching provides a brand-new route for manufacturing high-performance 3D architecture substrates for SERS applications.

Rapid detection of malachite green in fish and water based on the peroxidase-like activity of Fe3O4NPs enhanced with aptamer

This study attempted to fabricate a novel colorimetric method for the quantitative detection of malachite green (MG) residues in fish and water samples. Based on the recognition of the detection target and the enhancement of the peroxidase-like activities of Fe3O4NPs by MG-aptamer, a colorimetric method was established for MG detection. The detection limit (3α/κ, n = 9) was 16.7 μg kg–1, and the detection linear range was 0.06–2.38 μmol L–1. The recovery rates by standard addition in fish and water ranged from 90.1% to 119% with standard deviations (n = 3) of less than 6.6 %, and was well validated by a HPLC method. The detection procedure could be completed within 1 h. Therefore, the detection method was simple, stable, and reliable, and could be used to detect MG residues rapidly and accurately in fish and aquaculture water.

Durable and flexible Ag-nanowire-embedded PDMS films for the recyclable swabbing detection of malachite green residue in fruits and fingerprints

Swab sampling for the trace surface-enhanced Raman scattering (SERS) analysis of an aromatic dye (e.g., malachite green, MG) residue in fruits as well as fingerprints is promising due to its practical utility and efficiency in food security and forensic science. However, the durability and recyclability of the SERS substrates pose an enormous challenge. In this study, a novel flexible film was constructed by embedding a commercial Ag nanowire suspension into a polydimethylsiloxane film (Ag NWs@PDMS), which simultaneously exhibits SERS activity, durability and recyclability. High SERS performance was still maintained, even against 20 times stretchability, corrosion by HNO3, destruction by ultrasonication and a broad working temperature of −20 ℃ to 80 ℃. Excellent recyclability for MG sensing was achieved in ten cycles. Ag NWs@PDMS was successfully used for the quantitative detection of MG in juices of fruits (such as apple and pear) by drop dripping, with a limit of detection of 10 nM and good anti-interference. Meanwhile, the sensitive detection of the MG residue (only 3 ng/cm2) on fruits was enabled by the on-site surface swabbing by recycling for five cycles. Portable detection of the MG residue was further achieved from the 10th fingerprint after successively touching a dye drop onto the functional film combined with a portable Raman spectrometer.

Detection of malachite green residue in aquaculture water by using a rare earth fluorescence probe

Detection of malachite green residue in aquaculture water by using a rare earth fluorescence probe

Determination of Malachite Green Residue in Aquatic Products Based on Three-Dimensional Fluorescence Spectrum

Determination of Malachite Green Residue in Aquatic Products Based on Three-Dimensional Fluorescence Spectrum

Development and Validation of Analytical Methodologies for the Determination of malachite green (MG), leucomalachite green (LMG), crystal violet (CV) and leucocrystal violet (LCV) residues in Fish by using LC-MSMS

Development and Validation of Analytical Methodologies for the Determination of malachite green (MG), leucomalachite green (LMG), crystal violet (CV) and leucocrystal violet (LCV) residues in Fish by using LC-MSMS

Health risk assessment of toxicologically relevant residues in emerging countries: A pilot study on Malachite Green residues in farmed freshwater fish of Armenia

Malachite Green (MG) has a worldwide application in aquaculture as a therapeutic agent; however, its use in food producing animals is illegal, due to potential carcinogenicity and persistence of residues. This pilot study, the first conducted in Armenia, aimed to determine the concentration of MG residues in flesh of fish grown in artificial ponds of Armenia and conduct dietary exposure assessment to characterize possible health risks to consumers.Detection of MG residues, including the major metabolite leucomalachite, was carried out in 29 fish composite samples by ELISA. The results were confirmed by LC-MS/MS. To determine fish consumption values, a food frequency questionnaire was used. Possible health risks were evaluated by calculating the Margin of Exposure (MOE) based on BMDL of 13 (neoplastic effects) and 6 (non-neoplastic effects) mg/kg bw.In 34.5% of the investigated fish samples MG residues exceeded the minimum required performance limit. For BMDL10 and BMDL0.5, the MOEs ranged 3.36E+06–3.37E+07 and 1.55E+06–1.55E+07, respectively. The MOE for neoplastic effects was more than 10,000 and for non-neoplastic effects was more than 100. The results do not indicate public health concerns. However, the results highlight issues concerning the illegal use of MG in Armenian aquaculture, which deserves further attention.

Facile synthesis of Au nanoparticle-coated Fe3O4 magnetic composite nanospheres and their application in SERS detection of malachite green.

A facile method for synthesizing Au nanoparticle-coated Fe3O4 magnetic composite nanospheres (Fe3O4@Au MCS) via seed-mediated growth and iterative reduction is reported. The nanospheres were then successfully used to detect malachite green (MG) residues in water bodies via surface-enhanced Raman scattering (SERS) technique. Fe3O4@Au MCS has excellent optical properties and superparamagnetism; it can be dispersed into the solution to fully adsorb target molecules and then collected with a magnet to increase the molecular density and the number of SERS hot spots. Magnetic enrichment was superior to conventional detection method. The limit of detection for MG was 10-7 M and the enhancement factor was 1.1 × 105. The logarithm of the SERS intensity of the characteristic peak at 1618 cm-1 exhibited a linear relationship with the logarithm of the MG concentration over the range of 10-3- 10-7 M, with a correlation coefficient of 0.966. The Fe3O4@Au MCS had good uniformity of SERS signals, with a 18.59% relative standard deviation for the SERS intensity. MG detection in aquaculture water conformed with the established quantitative regulations. The SERS spectrum calculated with density function theory for MG adsorbed on Fe3O4@Au MCS was very close to the experimental spectrum, which verified enhancement by the substrate. Overall, Fe3O4@Au MCS enabled ultrasensitive, quantitative SERS detection of MG.

Controllable In-Situ Growth of Silver Nanoparticles on Filter Paper for Flexible and Highly Sensitive SERS Sensors for Malachite Green Residue Detection.

In this work, a series of highly flexible and sensitive surface-enhanced Raman scattering (SERS) substrates were fabricated by the in-situ growth of silver nanoparticles (AgNPs) on polydopamine (PDA) templated filter papers (FPs), based on mussel-inspired surface chemistry. The obtained FP@PDA@AgNPs strips exhibited high sensitivity and reproducibility with Rhodamine 6G (R6G) probe molecules, with a calculated detection limit of approximately 10−10 M. More critically, these FP@PDA@AgNPs strips could be used as outstanding flexible SERS sensors to quickly collect and detect malachite green (MG) residues on fish scales, crab shells and shrimp skins by a swabbing extraction method. The detection limits for MG residues were calculated to be approximately as low as 0.04635 pg/cm2, 0.06952 pg/cm2 and 0.09270 pg/cm2, respectively. This facile and efficient strategy could to be utilized as a universal approach to fabricating a variety of flexible, cheap and portable SERS sensors for surface contamination analysis, and has great potential in the environmental scientific analysis and food safety monitoring fields.

Simultaneous Determination of Malachite Green, Chloramphenicols, Sulfonamides, and Fluoroquinolones Residues in Fish by Liquid Chromatography-Mass Spectrometry.

A fast-analytical method using simplified extraction has been developed for the simultaneous determination of 42 compounds from 4 different classes of veterinary drugs (amphenicols, triphenylmethane, fluoroquinolones, and sulfonamides) in fish by reverse phase liquid chromatography-tandem mass spectrometry. The selection of extraction reagents was optimized using different types of microfiltration membrane, mobile phase, and LC column. Samples were extracted using 0.4% hydrochloric acid in acetonitrile and ethyl acetate and then were cleaned up using solid-phase extraction Cleanert Alumina N columns (500 mg) and Oasis hydrophilic-lipophilic balance (HLB) cartridges. The chromatographic separation was performed on a XR-ODS C8 column using a mobile phase of (A) 0.1% formic acid and 2 mM ammonium acetate and (B) 0.1% formic acid acetonitrile at a flow rate of 0.25 mL·min−1. The results indicated 67.7–112.8% recovery of 42 compounds with an intra- and interday relative standard deviations less than 10%. The limits of quantification for analytes were in the range of 0.3–1.0 μg kg−1 for samples which were satisfactory to support future surveillance monitoring. The method applicability was checked by analyzing 30 fish samples collected from local markets. Two fish samples surpassed the established MRL of 100 μg kg−1 with values of 104 μg kg−1 and 112 μg kg−1.

Surface-enhanced Raman spectroscopy with partial least squares regression for rapid and accurate detection of malachite green in aquaculture water using large-size gold nanoparticles

Malachite green is not used in aquaculture owing to its severe toxic effects on humans and other living organisms. The presence of this compound in fishery water should be quantified and reported in all water quality reports. In this paper, a method based on surface-enhanced Raman scattering combined with partial least squares regression for rapid, accurate, reliable, and sensitive detection of trace malachite green in fishery water is described. A prepared sol of 100-nm-size gold particles was used as an active substrate for Raman spectral data acquisition. Three parameters that affect detection, namely, the volume of gold nanoparticles (400 µL), the volume of sodium chloride (300 µL), and the adsorption time (8 min) were optimized in single-factor experiments. Under the optimal condition, the proposed method demonstrated a wide linear range of detectable concentrations (0.01–5.0 µmol/L) and the limit of detection was 2.7 × 10−9 M. The proposed method successfully detected spiked malachite green in fishery water samples, with satisfactory recoveries and relative standard deviations. Thus, this study suggests a rapid, simple, accurate, and sensitive approach for detecting malachite green residues in fishery water samples, which is promising for wide applications in environmental monitoring and food safety.