Melamine Residues Research Articles

Development of QuEChERS method for simultaneous detection of cyromazine and melamine residues in eggs

A quick, easy, cheap, effective, rugged and safe (QuEChERS) method was developed for detection of cyromazine (CYR) and melamine (MEL) residues using High Pressure Liquid Chromatography with UV detector (HPLC-UV). Analytes were separated on Chromasol® C18 column (4.0 ×250 mm, pore size 5 µm) using mobile phase of 0.05% trifluoroacetic acid (TFA) and acetonitrile (ACN) delivered in gradient mode at a flow rate of 1 mL min−1. Homogenized egg sample was extracted using solution comprising 99.5% ACN and 0.5% of 0.1 M hydrochloric acid in the presence of MgSO4, calcium silicate and celite 545 as adsorbents. Extract was subjected to liquid-liquid partitioning with n-hexane for the removal of fats. Optimization of quantity of adsorbent chemicals was done by Box-Behnken statistical design (BBD). For CYR, the Limit of Detection (LOD) and Limit of Quantitation (LOQ) of the method were found to be 5.3 and 16.0 µg kg−1, respectively; and for MEL 11.4 and 34.7 µg kg−1, respectively. The average recoveries of the analytes were 87.3% and 102.4% for MEL and CYR, respectively, indicating good accuracy while, Percent Relative Standard Deviation (% RSD) of less than 10% indicated good precision. Further, the R2 values greater than 0.9998 indicated good linearity of the newly developed method. The analysis of real samples reveled that CYR could be detected in eggs only if layer farms had a history of the usage of CYR in the poultry feed. Overall, the performance of the method was optimum and less expensive to serve the purpose of routine monitoring of CYR and MEL residues in eggs.

Residue degradation and metabolism of dinotefuran and cyromazine in Agrocybe aegerita: A risk assessment from cultivation to dietary exposure

Sensitive, simple and quick methods for determination of dinotefuran, cyromazine, and the metabolites 1-methyl-3-(tetrahydro-3-furylmethyl) guanidine (DN), 1-methyl-3-(tetrahydro-3-furylmethyl) urea (UF), and melamine in Agrocybe aegerita were established and validated by ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). The dissipation and residues of these compounds in A. aegerita were investigated. The field results showed that dinotefuran and cyromazine dissipated rapidly with half-lives ranging from 24.9 h to 38.5 h. The terminal residues of total dinotefuran (the sum of dinotefuran and its metabolites), cyromazine, and melamine in fresh mushroom samples collected with sampling intervals of 3 d to 6 d ranged from 0.089 to 0.652 mg/kg, 0.593 to 2.054 mg/kg, and 0.002 to 0.005 mg/kg, respectively. During the drying processes of A. aegerita, the processing factors of dinotefuran, cyromazine, DN, UF, and melamine were 0.028, 0.012, 0.301, 0.002, and 0.001, respectively. Given that cyromazine and dinotefuran are not registered for use on A. aegerita, dietary risk was assessed. Based on a consumption survey, risk quotient (RQ) values significantly below 1 implied that the risk of A. aegerita consumption was acceptable, although the risk for children was relatively higher. The findings could provide valuable guidance for the appropriate use of these insecticides in A. aegerita cultivation and serve as a scientific reference for setting corresponding maximum residue limits (MRL) in China.

Development of a new phosphorescence sensor based on surface molecularly imprinted Mn-doped ZnS quantum dots for detection of melamine in milk products

This paper presents a novel room temperature phosphorescence sensor (IMIPs-ZnS QDs RTP sensor) based on inorganic surface molecularly imprinted polymers and Mn-doped ZnS quantum dots (QDs) for the rapid detection of trace melamine (MEL) in commercial milk products. The surface of Mn-ZnS QDs was modified with 3-(mercaptopropyl) trimethoxy silane (MPTS). Then, MEL, 3-aminopropyltriethoxysilane (APTES) and tetraethoxysilane (TEOS) were used as a template/target molecule, functional monomer, and cross-linker, respectively. IMIPs-ZnS QDs RTP sensor was characterized using spectrofluorimeter, UV–Vis spectrophotometer, FT-IR, transmission electron microscope (TEM), and X-ray photoelectron spectrometer (XPS).Detection time and linear range for IMIPs-ZnS QDs RTP sensor were 30 min and 4.0–79.2 µM with a correlation coefficient value of 0.9946, respectively. Furthermore, LOD and LOQ values were calculated using Stern-Volmer equation as 0.29 and 0.97 µM, respectively. Thus, IMIPs-ZnS QDs RTP sensor was successfully applied for the detection of MEL residue in milk samples. Recovery values were in the range of 88.62–90.22 % with relatively high precision values (0.57–0.92 % RSD). Our findings indicate that the developed IMIPs-ZnS QDs RTP sensor exhibits high sensitivity and selectivity towards the MEL in milk sample containing potentially relatively high number of interfering compounds.

An air-assisted dispersive liquid phase microextraction method based on a hydrophobic magnetic deep eutectic solvent for the extraction and preconcentration of melamine from milk and milk-based products.

In the current research, a fast and sustainable air-assisted hydrophobic magnetic deep eutectic solvent-based dispersive liquid phase microextraction followed by UV-Vis spectrophotometry measurements was optimized for the extraction and determination of melamine in milk and milk-based products. The central composite design was applied for the optimization of factors affecting the recovery of melamine. Quantitative extraction of melamine was achieved using hydrophobic magnetic deep eutectic solvents prepared from a mixture of octanoic acid, aliquat-336, and cobalt(II) chloride. The optimum conditions for extraction were found as follows: 6 extraction cycles, pH 8.2, extraction solvent volume 260µL, and acetone volume 125µL.Interestingly, a centrifugation step was not required to achieve phase separation. Under the optimum conditions, melamine was determined in the linear range of 3-600ngmL-1, the limit of detection (3Sblank/m) of 0.9ngmL-1, and the enrichment factor of 144. The validation of the method was investigated by the analysis of reference materials. Consequently, the method was successfully applied for the analysis of melamine residues in milk and milk-based products.

Vortex-assisted microextraction of melamine from milk samples using green short chain ionic liquid solvents coupled with high performance liquid chromatography determination

Melamine is added illegally to milk and dairy products to increase the amount of apparent protein. This organic nitrogen rich chemical compound has been of great challenge in food safety based on its adverse effect on health. Therefore, the extraction and determination of melamine from milk is necessary. Recently, ionic liquid (ILs) as solvent usage has been noticeable for low melting point, low toxicity, high thermal stability, and high extraction capabilities in a wide range of separation processes. ILs are introduced as organic–inorganic salts and green solvents in microextraction preparation. Therefore, in this study, three ionic liquids ([C6mim][NTF2], [C4mim][NTF2] and [C2mim][NTF2] ILs) were prepared and employed as an extraction solvent in dispersive liquid–liquid microextraction (DLLME) of melamine from milk samples followed by HPLC-UV. The selected ILs were designed using three types of alkyl-imidazolium (as the short organic cations) and bis (tri fluoro methyl sulfonyl) imide as anion and characterized by ATR-FTIR spectra, carbon, and hydrogen Nuclear Magnetic Resonance spectroscopy (H&C-NMR) and energy-dispersive X-ray spectroscopy (EDX). These techniques confirmed the formation of functional groups, the structure of hydrogen and carbon atoms, and various elements of ionic bond between imidazolium and bis (tri fluoro methyl sulfonyl) imide. In the next step, the effect of significant parameters, including type and volume of ILs, adsorption time, pH of the sample solution, and sample volume, were optimized. Under the optimal conditions, the limits of detection (LOD), limits of quantification (LOQ), and linearity range were obtained 63.64 µg kg−1, 210.03 µg kg−1, and 210.03–1000 µg kg−1, respectively, for as prepared [C6mim][NTF2] as the best ILs. Notably, the achieved LOQ was lower than the maximum residue level (MRL) for the melamine residue in dairy products. Eventually, the proposed method was applied to detect melamine in milk samples, and the relative recoveries were examined as 79.6–105.0 %.

Melamine-Based Nanocomposites for Selective Dopamine and Uric Acid Sensing

The formation process of carbon dots (CDs) is mostly polymerization; recently, studies on the polymerization of carbon families (graphene oxide and C60) have been receiving exciting attention. Herein, a protocol of prepolymerization and electropolymerization of monomer (melamine) and nanomonomer (CDs fixed melamine residues) was proposed to prepare a nanocomposite for selective dopamine (DA) and uric acid (UA) sensing. The nanomonomer was prepared by hydrothermal prepolymerization of melamine, and then the nanocomposite was formed in situ by electropolymerization of the CDs/carboxylated multiwalled carbon nanotubes (MWCNTs-COOH)-modified glassy carbon electrode (GCE) in KCl solution. Scanning electron microscopy, transmission electron microscopy, energy-dispersive spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy, cyclic voltammetry, electrochemical impedance spectroscopy, and differential pulse voltammetry were used to characterize the properties of the nanocomposite. Under optimal conditions, the electrochemical sensor shows selectivity and a wide linear range from 0.1 to 10 μM for DA and 0.1 to 200 μM for UA, with the detection limit of 0.023 and 0.064 μM (S/N = 3) in the presence of AA, respectively. In addition, the proposed sensor was also applied to selectively test DA and UA in the presence of 500 μmol/L AA in real samples with satisfactory recovery.

Determination of cyromazine and Melamine residues in poultry eggs

Determination of cyromazine and Melamine residues in poultry eggs

Screening , analysis and health impact of melamine residues in milk powder and dry milk infant’s formula by ELISA in Mansoura city, Egypt.

Objective: In recent years, milk and dairy products have been associated with several types of adulterations that have hazard effects onto our health. One of the most famous types of adulteration that rich with nitrogen is melamine. Subsequently, this study aimed to determination the prevalence of melamine in some milk products and analysis it using ELISA. Materials and Methods: Fifty samples of imported and local dry milk infant formula (25 each), and 25 samples of imported milk powder, were purchased from different markets and outlets in Mansoura city, Egypt. Theses samples were closely undertaken and analyzed to stand up on melamine contents of them. Results: The results of the examined samples were matched within the permissible codex alimantarius (1995). The limits of detection for melamine in dry milk infant formula and milk powder were 1 mg/kg and2.5 mg/g, respectively. Conclusion: From our results, we can say that ELISA kits is an effective and more economical tool for analysis of suspected milk samples containing melamine instead of extensive sample preparation or other expensive methods.

Electrodeposition immobilized molybdenum disulfide quantum dots and their electrochemiluminescence application in the detection of melamine residues in milk powder

In this paper, one-step hydrothermal and electrodeposition methods were used to prepare a MoS2 quantum dot (QD) solid-phase electrochemiluminescent (ECL) electrode for the detection of melamine residues in milk powder. With the assistance of chitosan, MoS2 QDs fixed by the one-step electrodeposition method show better ECL performance than those by traditional deposition methods due to better dispersibility and stability. Based on the quenching of the MoS2 QDs ECL signal by melamine, quantitative detection of melamine in the sample was performed. The structure and morphology of a MoS2-CHIT/indium tin oxide (ITO) solid-phase ECL electrode were characterized by TEM and XPS, and melamine was detected by the ECL method using a three-electrode system. The proposed sensor exhibited good linearity in the range of 1.00 × 10-11 to 1.00 × 10-7 mol L-1 (ΔI = 12 100.62 + 1009.93 lg c (mol L-1), R2 = 0.997), and the method shows the advantages of simplicity and sensitivity compared to traditional detection methods. The interference of common ions in milk powder on the modified electrode was within 5%, and the recovery rate of real sample detection was within 97-98%. As a result, the proposed method is suitable for detecting melamine residues in milk powder.

Evaluation of cyromazine transferred from feed to chicken products and subsequent assessment of dietary risks to Chinese consumers.

In this work, levels of cyromazine and its metabolite melamine in chicken products and its transfer factors (TFs) and dietary risks assessment for Chinese consumers are presented. Cyromazine was added to chicken feed at doses of 5, 25, and 50mg/kg for 42 days. Cyromazine residues were found in frequently consumed chicken products (meat, heart, liver, gizzard, and eggs), with liver and eggs displaying the highest concentrations (0.935 and 1.281mg/kg, respectively). Low levels of melamine residues (<0.029mg/kg) were detected in chicken products from chickens treated with 25 and 50mg/kg cyromazine, but not in eggs from chickens treated with 5mg/kg cyromazine. The TFs for the investigated chicken products varied from 0.0074 to 0.0229 across the dosage levels. The chronic exposure assessment showed that 0.001 to 0.190% of the acceptable daily intake (0.06mg/kg body weight [b.w.]/day) of cyromazine was consumed through chicken products among the various age and gender groups of Chinese consumers. The acute exposure assessments of different age and gender groups were 0.0004% to 0.178% of the acute reference dose (0.1mg/kg b.w.). Although the results suggest that the risk associated with cyromazine residues in chicken products was low in China, the possible risk associated with cyromazine residues in chicken products should not be ignored while cyromazine remains a legal feed additive. PRACTICAL APPLICATION: The present analytical method could be used for cyromazine and melamine detection in different chicken products, and dietary risk assessments of cyromazine provided a support for the work of regulatory bodies to conduct surveillance programs regarding food safety evaluation of cyromazine.

Development of a highly sensitive voltametric sensor for trace determination of melamine residues in milk and water samples

Melamine (MEL) is a key and broadly used trade chemical that is risky to human health and environment. Hence, a method comprising a preanodized glassy carbon electrode (GCE*) for sensitive analysis of MEL has been developed. The electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), and surface area data confirmed the preanodization of the GCE. The results highlight the efficacy and the compatibility of the GCE* protocol for sensitive detection of trace levels of MEL. The method was based upon the indirect differential pulse voltammetric (DPV) sensing of MEL depending on its competition with uric acid (UA) as a recognition element at the surface of GCE*. The electrochemical oxidation of UA at GCE* showed one well defined anodic peak at 0.23 V vs. Ag/AgCl electrode. Under the optimized parameters, the linearity range of the method was calculated as 2.0 × 10−9–8.0 × 10−9 M (0.252–1.009 µg.L−1) with an accuracy of 99.21 ± 5.02 (R2 = 0.9969). The lower limits of detection (LOD) and quantization (LOQ) were 6.0 × 10−10 M (0.075 µg.L−1) and 2.0 × 10−9 M (0.252 µg.L−1), respectively. Intra-day and inter-day precisions of the method were in the range 98.46 ± 5.02 and 99.21 ± 5.84%, respectively. The average relative standard deviation (RSD) at 2.0 × 10−7 M of MEL for successive measurements (n = 3) was ± 3.0%. Analysis of MEL in milk powder and water samples determined using the developed DPV procedures gave satisfactorily recoveries ranged from 96.11 to 97.01% for low and high levels of MEL in a variety of milk samples with relative standard deviations (RSDs) over the range of ± 4.1% 0.32%-3.61%. The method offered a significant improvement for trace determination of MEL in a variety of milk and milk powder samples in terms of efficient, rapid, economical, and miniaturized sample preparation methods, which yielded fewer matrix effects compared with SPE method. The established method is expected to be widely applied for analysis of MEL at trace levels in the future.

A simple and quick ionic liquid-based ultrasonic-assisted microextraction for determination of melamine residues in dairy products: Theoretical and experimental approaches

In this study, a simple and quick ionic liquid- based ultrasonic-assisted microextraction (IL-UA-ME) procedure has been improved for extraction of melamine in dairy productsfollowed by UV–VIS spectrometry. For the analysis of stability and reactivity of melamine and its some metal complexes, quantum chemical parameters like frontier orbital energy-HOMO-LUMO energy gap, hardness and softness were calculated using computational chemistry tools. The results regarding to stability analysis made considering density functional theory showed that theoretical data obtained are compatible with experimentally obtained results, and Fe-melamine complex is more stable compared to others. Under optimum conditions, the linearity was in the range of 0.05–400 ng mL−1 with detection limit of 0.015 ng mL−1. Following the validation studies, recovery and relative standard deviation were obtained in range of 92.5–104.3% and 1.4–2.1%, respectively. The first research article in which experimental and theoretical studies are used together for the determination of melamine in dairy products.

Effect of dietary melamine concentrations on growth performance, excreta characteristics, plasma measurements, and melamine residue in the tissue of male and female broiler chickens

The objectives of the current experiment were to investigate the effect of dietary melamine concentrations on growth performance, excreta characteristics, plasma measurements, and melamine residue in the tissue of male and female broiler chickens. Finally, the safe levels of melamine in broiler diets were determined based on BW gain (BWG) and melamine residue in the breast meat. A total of 1,008 1-d-old Ross 308 male and female broiler chickens were allotted to 1 of 7 dietary treatments within each sex in a completely randomized design. There were 6 replicates per treatment and each replicate consisted of 12 birds. Dietary melamine concentrations were set to 0; 250; 500; 750; 1,000; 5,000; or 10,000mg/kg by adding a purified form of melamine. Diets were provided to birds on ad libitum basis for 35 d. Results indicated that no significant interaction between sex and dietary melamine concentrations was observed for all measurements. The BW, BWG, and feed intake for birds fed diets containing 10,000mg/kg melamine were less (P < 0.05) than for those fed other diets. Melamine residues in the kidney and breast for birds fed diets containing 10,000mg/kg melamine were greater (P < 0.05) than for birds fed other diets. The toxic level of dietary melamine based on BWG was determined by the one-slope broken-line analysis. The resulting equation was Y = 1,851 - 0.0404 × (X - 4,292), which indicated that a greater than 4,292mg/kg melamine in diets was toxic to broiler chickens. The safe level of dietary melamine to limit melamine residue in the broiler breast was analyzed using the linear regression, which indicated that the safe level of melamine in broiler diets was 814mg/kg. In conclusion, less than 814mg/kg melamine in broiler diets should be maintained to satisfy human food safety regulations for melamine residue in the breast meat of broiler chickens.

Colloidal silver-based lateral flow immunoassay for rapid detection of melamine in milk and animal feed

An immunosilver chromatographic strip based on a monoclonal antibody was developed for the detection of melamine (MEL) residues in milk and animal feed. Colloidal silver nanoparticles (AgNPs), of a diameter of approximately 10.4 nm, were surface-modified with trisodium citrate dehydrate (TSC) in order to improve their stability and dispersion. The anti-MEL monoclonal antibody (mAb) was successfully immobilized on the surface of AgNPs by ionic interactions and characterized using XRD, UV–Vis, TEM and XPS analyses. Surface modification of Ag-mAb conjugates with varying cross-reactivity and thermo-stability was employed to design and prepare labels for use in a lateral flow immunoassay (LFIA) to examine whether these factors affect the performance of the assay. The results showed that no cross-reactions with homologues cyanuric acid, ammeline or ammelide were found, and the test strip remained stable after storage for one year at room temperature. Under optimized conditions, a detection limit of 0.30 ppm for standard melamine was achieved, and limits of detection of 0.750 ppm and 0.875 ppm were obtained in milk and animal feed, respectively.

Ultrasensitive anti-melamine monoclonal antibody and its use in the development of an immunochromatographic strip

ABSTRACT The hapten 1 which was formed by the reaction of 2-chloro-4,6-diamine-1,3,5-triazine (CAAT) with 6-aminocaproic acid, conjugated with keyhole limpet haemocyanin to prepare the immunogen. And coating antigen was prepared by the coupling of ovalbumin and hapten 2 which was synthesized by the reaction of CAAT and 3-mercapto propionic acid. Based on immunological and cell fusion technology, the anti-melamine monoclonal antibody was prepared and characterized. The half inhibitory concentration of the antibody for melamine was 1.8 ng/mL, and the linear range was 0.61–5.56 ng/mL. An immunochromatographic (ICT) strip, based on the antibody, was developed for the rapid detection of melamine residues in milk samples. The ICT strip had a visual cut-off value of 10 ng/mL for milk samples. Therefore, the colloidal gold immunoassay with the advantage of high affinity and sensitivity can be used for the ultrasensitive detection of melamine residues in milk samples.

Determinations of Melamine Residue in Infant Formula Brands Available in Iran Market Using by HPLC Method.

The contamination of melamine was evaluated in 69 infants along with follow up formula samples collected from the market for the first time in Iran using HPLC method. Since there are no previous data concerning the contamination level of melamine in all brands of infant formula samples consumed using the HPLC method in Iran, this study is the first investigation in this regard. Our results showed that melamine contamination was found in 65% of samples, where mean and maximum levels of melamine were 0.73 ± 0.71 mg/kg and 3.63 mg/kg, respectively. The level of melamine in 10 out of 69 samples was higher than the maximum level set by the Codex Alimentarius in infant food (1 mg/kg). Melamine was determined in 67.8% and 50% of domestic and imported samples, respectively. The estimated daily intake was designed in two scenarios: it was calculated based on the mean level of melamine contamination and maximum level of melamine in the samples. In both scenarios, our results showed that melamine intake across all age groups is lower than the tolerable daily intake (TDI) of 0.2 mg/kg body weight, suggested by WHO (0.2 mg/kg body weight). Thus, it seems that the current levels of melamine in infant and follow up formula purchased in Iran pose no health risk for infants.

Changes in porcine growth, biochemical parameters, histopathology, and melamine residue levels in tissues induced by consumption of melamine and cyanuric acid

Changes in porcine growth, biochemical parameters, histopathology, and melamine residue levels in tissues induced by consumption of melamine and cyanuric acid

Liquid chromatography-mass spectrometry method for evaluating the dissipation dynamics of cyromazine and its metabolite in Agaricus bisporus and dietary risk assessment.

Providing guidance on the reasonable use of pesticide in agricultural production is of particular importance for ensuring food safety. In the present study, a field trial was performed to study the dissipation and accumulative pattern of cyromazine (CA) and its metabolite in Agaricus bisporus (A. bisporus) cultivation. An ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was first developed and validated for the determination of CA and melamine (MEL) in the casing soil and fruiting body. During the cultivation period, the dissipation rates of CA in the casing soil were between 51.57 and 63.48% at three dose groups. The fruiting body presented higher accumulation ability for MEL compared with CA. The terminal residues of MEL never exceeded the maximum residue limits (MRLs) in food. In addition, the intake health risk from the CA and MEL residues in the fruiting body were negligible to humans. This study will help to provide valuable guidance on the application strategies of CA in A. bisporus cultivation.

1001 Effect of dietary melamine concentrations on performance and tissue melamine residue in female broiler chickens

1001 Effect of dietary melamine concentrations on performance and tissue melamine residue in female broiler chickens

1000 Effect of dietary melamine concentrations on performance and tissue melamine residue in male broiler chickens

1000 Effect of dietary melamine concentrations on performance and tissue melamine residue in male broiler chickens