ammeline and ammelide

Melamine (MEL) and its derivatives are widely used in many consumer products, including furniture, kitchenware, and plastics. However, very limited knowledge exists on human exposure to MEL and its derivatives, especially in the indoor environment. Here, we determined the occurrence and distribution of 11 MEL derivatives in childcare facilities and estimated children's exposure through dust ingestion and dermal absorption. We analyzed dust and samples of nap mats, a commonly used item in many childcares, from eight facilities located in the United States. Eight MEL-based compounds were detected in dust, and total MEL concentrations ranged from 429 to 117,000 ng/g. The most abundant compounds found in the dust samples were MEL, cyanuric acid (CYA), ammeline (AMN), and ammelide (AMD), with median concentrations of 1620, 585, 1060, and 299 ng/g, respectively. MEL, CYA, AMN and 2,4,6-tris[bis(methoxymethyl)amino]-1,3,5-triazine (TBMMAT) were also detected in nap mats with median concentrations of 45.6, 19.8, 1510 and 2.5 ng/g, respectively. ΣMEL concentrations in mat covers (median 709 ng/g) were significantly higher than those in mat foam (median 15.1 ng/g). Estimated daily intakes (EDIs) of MEL and its derivatives via dust ingestion were two orders of magnitude higher than the EDIs through dermal absorption, but both were below the established tolerable daily intake levels. This is the first report on exposure to MEL and its derivatives in the childcare environment.

Topics: Air Pollution, Indoor; Child; Child Day Care Centers; Dust; Environmental Exposure; Humans; Skin Absorption; Triazines; United States

Melamine is used extensively in household products, such as furniture, dinnerware, and food utensils. Several studies have shown that melamine adversely affects kidney function. Nevertheless, little is known about urinary melamine concentrations, and its temporal variability. In this study, 213 first-morning-void urine samples were collected from 19 volunteers for over a month to assess longitudinal variability in concentrations of melamine and its three structural analogues, i.e., cyanuric acid, ammeline, and ammelide. Target analytes were found in all urine samples at mean concentrations of 3.3, 16, 0.99, and 0.62 ng/mL, for melamine, cyanuric acid, ammelide, and ammeline, respectively. Cyanuric acid was the major compound found in all urine samples, accounting for 74-80% of the total concentrations, followed by melamine (12-20%), ammelide (4-6%), and ammeline (2-4%). Gender- and age-related differences in melamine concentrations were observed, although no such pattern was found for cyanuric acid. After adjusting for creatinine, melamine and cyanuric acid concentrations were moderately predictable with inter-day intraclass correlation coefficients (ICCs) in the range of 0.541-0.763. Nevertheless, substantial inter-individual variation in melamine levels existed even after creatinine adjustment, as evidenced by low ICCs (0.008-0.108). Cumulative daily intake of melamine and cyanuric acid was calculated on the basis of urinary concentrations and the mean values were found to be at least 10-fold below the current tolerable daily intake.

Topics: Adult; Animals; Female; Healthy Volunteers; Humans; Male; Middle Aged; Reference Values; Triazines; Young Adult

Melamine-based resins are used extensively in laminates, plastics, coatings, glues, and dinnerware. Little is known, however, about the occurrence of melamine and its derivatives in the environment. In this study, a nationwide survey of melamine and its derivatives, namely ammeline, ammelide, and cyanuric acid, was conducted, using archived sewage sludge samples collected from 68 wastewater treatment plants in the United States (U.S.). The sum concentrations of four target compounds in sludge ranged from 34 to 1800 ng/g dry weight (dw), with a mean concentration of 240 ng/g dw; melamine (46%) and cyanuric acid (40%) collectively accounted for 86% of the total mass of analytes. No significant geographical variation in the concentrations of melamine and its derivatives in sewage sludge was found. The estimated emission of melamine and its derivatives via land-application of sludge was approximately 1600 kg/yr in the U.S. The hazard quotient values for melamine in sludge-amended soils ranged from 2.2 × 10

Topics: Environmental Monitoring; Sewage; Surveys and Questionnaires; Triazines; United States; Wastewater; Water Pollutants, Chemical

Melamine is a nitrogen-containing organic compound that is used in a wide range of products, including paints, plastics, and paper, as a flame retardant. A few studies have reported the occurrence of melamine and its derivatives in pet food, following a number of deaths of cats and dogs from kidney failure in 2007, which was attributed to melamine contamination in ingredients used in pet food. Nevertheless, studies that report the occurrence of melamine and its derivatives in pet urine are scarce. In this study, we measured melamine and its derivatives (i.e., ammeline, ammelide, and cyanuric acid) in dog (n = 30) and cat (n = 30) urine collected from Albany, New York, USA, during March through July 2017. The mean (±SD) concentrations of melamine, ammeline, ammelide, and cyanuric acid in dog urine were 21.1 ± 51.2, 2.3 ± 3.8, 9.9 ± 1 0.4, and 79.0 ± 105 ng/mL, respectively; the corresponding concentrations in cats were 21.4 ± 26.1, 1.2 ± 2.5, 6.1 ± 3.9, and 105 ± 94.6 ng/mL, respectively. No significant difference was observed in urinary concentrations of melamine derivatives between cats and dogs. Age and gender were important determinants of the concentrations of the target chemicals in cats and dogs. Cumulative daily intake of melamine and its derivatives was calculated on the basis of urinary concentrations and was found to be 10-500-fold below the tolerable daily intake.

Topics: Animal Feed; Animals; Cats; Dogs; Female; Flame Retardants; Food Contamination; Male; New York; Nitrogen; Triazines

Propazine is a s-triazine herbicide widely used for controlling weeds for crop production. Its persistence and contamination in environment nagatively affect crop growth and food safety. Elimination of propazine residues in the environment is critical for safe crop production. This study identified a microbial community able to degrade propazine in a farmland soil. About 94% of the applied propazine was degraded within 11 days of incubation when soil was treated with 10mgkg

Topics: Biodegradation, Environmental; Biomass; Denaturing Gradient Gel Electrophoresis; Genes, Bacterial; Microbial Consortia; Soil; Soil Microbiology; Soil Pollutants; Triazines

Milk-derived ingredients are widely used around the world in the manufacturing of nutritional products. They are prone to economically motivated adulteration with nitrogenous compounds such as melamine and its analogs in order to increase the nitrogen content of these ingredients. The need to rapidly screen milk-derived ingredients to detect adulteration is of paramount public health concern. A liquid chromatography/mass spectrometry (LC/MS)-based method using a single quadrupole mass spectrometer has been developed for the rapid frontline analysis of six nitrogenous protein adulterants, i.e. melamine, ammeline, ammelide, amidinourea, cyromazine and cyanuric acid, in three key milk-derived ingredients, i.e. whole milk powder, nonfat milk powder and whey protein concentrate.. The sample preparation scheme involves both 'dilute and shoot' as well as solid-phase extraction (SPE)-based methods. The 'dilute and shoot' scheme uses a tenfold dilution of sample with water followed by protein precipitation using 2% formic acid in acetonitrile. The SPE scheme involves tenfold dilution of sample with water, followed by protein precipitation using acetonitrile, and further cleanup through Strata Melamine SPE cartridges. Sample extracts were analyzed by hydrophilic interaction chromatography/single quadrupole mass spectrometry (HILIC/MS) in both positive and negative electrospray ionization mode. Accurate quantitation was achieved using stable isotope labeled internal standards.. A multi-day method validation study was conducted using three different milk-derived ingredients. Average accuracies, relative standard deviations (RSD) and method detection limits (MDL) for all analytes in whole milk powder were 65-118%, 7-11% and 0.9-30 mg/kg, using the 'dilute and shoot' extraction procedure. The SPE procedure results were 102-111%, 5-13%, and 0.4-2.5 mg/kg, respectively, for melamine, ammeline, ammelide and cyromazine only.. A rugged and simple to use analytical method to screen for the presence of nitrogenous economic adulterants in milk-derived ingredients has been developed for routine frontline use. Copyright © 2016 John Wiley & Sons, Ltd.

Topics: Animals; Chromatography, High Pressure Liquid; Food Analysis; Food Contamination; Limit of Detection; Milk; Milk Proteins; Nitrogen Compounds; Solid Phase Extraction; Spectrometry, Mass, Electrospray Ionization; Triazines; Urea

A novel molecularly imprinted solid-phase extraction-ultra-performance liquid chromatography (MISPE-UPLC) method for effective separation and simultaneous determination of cyromazine, melamine, and their metabolites (ammeline and ammelide) in milk samples was developed. Molecularly imprinted polymers (MIP) were synthesized in an ethanol-water system, with melamine as the template and methacrylic acid as the organic functional monomer. The MIP were applied as a specific sorbent for the selective solid phase extraction of cyromazine, ammelide, melamine and ammeline. The molecular recognition mechanism was investigated by molecular simulation and the experiment was validate by using Fourier transform infrared spectroscopy and (1)H nuclear magnetic resonance spectroscopy. A new mechanism based on the formation of both an amido group and hydrogen bonds was developed. A binding study demonstrated that the MIP showed excellent affinity to and high selectivity for melamine and related compounds. Under optimized conditions, we achieved good linearity of the calibration curves with correlation coefficients >0.999. Low limits of quantification (LOQ) for the method were determined to be 1.25, 1.25, 2.59, and 6.42 µg/kg for cyromazine, ammelide, melamine, and ammeline, respectively, which were 3 orders of magnitude smaller than the maximum residue limit (MRL). The high sensitivity of this method allows detection at the microgram per kilogram level. The proposed MISPE-UPLC method is a highly selective and sensitive method for determination of cyromazine, melamine, and their metabolites (ammeline and ammelide) for use in the control and quality assurance of milk.

Topics: Animals; Chromatography, High Pressure Liquid; Limit of Detection; Magnetic Resonance Spectroscopy; Methacrylates; Milk; Molecular Imprinting; Polymers; Solid Phase Extraction; Triazines

We have developed a method for the determination of melamine (MEL), ammeline (AMN), and ammelide (AMD) by surface-assisted laser desorption/ionization mass spectrometry (SALDI-MS) using gold nanoparticles (Au NPs). The major peaks for MEL, AMN, and AMD at m/z 127.07, 128.05, and 129.04 are assigned to the [MEL + H](+), [AMN + H](+), and [AMD + H](+) ions. Because the three tested compounds adsorb weakly onto the surfaces of the Au NPs through Au-N bonding, they can be easily concentrated from complex samples by applying a simple trapping/centrifugation process. The SALDI-MS method provides limits of detection of 5, 10, and 300 nM for MEL, AMN, and AMD, respectively, at a signal-to-noise ratio of 3. The signal variation for 150-shot average spectra of the three analytes within the same spot was 15%, and the batch-to-batch variation was 20%. We have validated the practicality of this approach by the analysis of these three analytes in infant formula and grain powder. This simple and rapid SALDI-MS approach holds great potential for screening of MEL in foods.

Topics: Citric Acid; Edible Grain; Flour; Gold; Hydrogen-Ion Concentration; Infant Formula; Limit of Detection; Metal Nanoparticles; Quaternary Ammonium Compounds; Reproducibility of Results; Signal-To-Noise Ratio; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Triazines

Resins based on melamine-formaldehyde and related analogues such as methylolated melamine are used to cross-link coatings used inside food cans and on the metal closures of glass jars. Thirteen commercially coated cans and closures representing 80% of the European market were tested using simulants under realistic industrial heat-processing conditions for canned and jarred foods. The food simulants and the retort conditions used were 3% acetic acid for 1 h at 100 °C and 10% ethanol for 1 h at 130 °C. The highest migration level seen for melamine into simulant was 332 µg kg⁻¹. There was no detectable migration of the melamine analogues cyanuric acid (<1 µg kg⁻¹) or ammelide (<5 µg kg⁻¹) from any sample. Twelve of the thirteen samples released no detectable ammeline (<5 µg kg⁻¹) but the coating giving the highest release of melamine did also release ammeline at 8 µg kg⁻¹ with the higher of the two process temperatures used. Migration experiments into food simulant and foods themselves were then conducted using two experimental coatings made using amino-based cross-linking resins. Coated metal panels were exposed to the food simulant 10% (v/v) aqueous ethanol and to three foodstuffs under a range of time and temperature conditions both in the laboratory and in a commercial food canning facility using proprietary time and temperature conditions. The highest migration into a food was 152 µg kg⁻¹ from the first coating processed for a long time at a moderate sterilisation temperature. The highest migration into simulant was also from this coating at 220 µg kg⁻¹ when processed at 134 °C for 60 min, dropping to 190 µg k⁻¹ when processed at 123 °C for 70 min. Migration from the second coating was quite uniformly two to three times lower under all tests. These migration results were significantly higher than the levels of melamine extractable using 95% ethanol at room temperature. The experiments show that commercial canning and retorting can be mimicked in an acceptable way using laboratory tests with an autoclave or a simple pressure cooker. The results overall show there is hydrolytic degradation of the melamine cross-linked resins to release additional melamine. There is a strong influence of the temperature of heat treatment applied with foods or simulants but only a minor influence of time of heating and only a minor influence, if any, of food/simulant acidity.

Topics: European Union; Food Contamination; Food Packaging; Food Preservation; Food, Preserved; Hot Temperature; Hydrogen-Ion Concentration; Hydrolysis; Resins, Synthetic; Solubility; Time Factors; Triazines

A liquid chromatography-tandem mass spectrometry-based isotope dilution method was developed for the analysis of the triazine compounds melamine (MEL), ammeline (AMN), ammelide (AMD) and cyanuric acid (CYA) in infant formula samples purchased in Canada in 2008 for the purpose of a combined exposure and risk assessment. Infant formula samples were extracted with 1:1 acetonitrile-water, cleaned up on disposable ion-exchange solid-phase extraction cartridges, and analysed by ultra-high-performance liquid chromatography-tandem mass spectrometry. MEL and CYA were detected in almost all infant formula products: the highest concentrations observed were 0.32 mg kg(-1) MEL and 0.45 mg kg(-1) CYA. Samples that were relatively high in MEL in this survey tended to be low in CYA, and vice versa. Concentrations of AMN and AMD were very low in all samples. The total of MEL-related compounds (sum of all four analytes) in all samples was below the interim standard of 0.5 mg kg(-1) for infant formula products established by Health Canada.

Topics: Canada; Carbon Isotopes; Chromatography, High Pressure Liquid; Food Contamination; Food Inspection; Humans; Indicator Dilution Techniques; Indicators and Reagents; Infant; Infant Formula; Limit of Detection; Reproducibility of Results; Risk Assessment; Solid Phase Extraction; Soy Foods; Spectrometry, Mass, Electrospray Ionization; Tandem Mass Spectrometry; Triazines

The adulteration of food products with melamine to inflate the nitrogen content necessitates the establishment of analytical methods that can distinguish between proteinaceous ingredients and such adulterants. The specificity and ability to detect melamine by two commercial enzyme-linked immunosorbent assay (ELISA) kits were evaluated along with three protocols for sample preparation. Both ELISAs displayed cross-reactivity with ammeline, but neither was able to detect ammelide or cyanuric acid, indicating either a requirement for the 4,6-diamino-1,3,5-triazine structure or inability to bind 1,3,5-triazine-4,6-diones. The limits of detection for melamine in powder infant formula ranged from 0.2 to 3 microg/g depending on the ELISA kit and the method used to prepare the sample. The limits of detection for melamine in liquid infant formula and wheat products were <1 microg/ml and <2.5 microg/g, respectively. The ELISA kits provide an effective alternative for the analysis of samples suspected of containing melamine without relying on extensive sample preparation or expensive instrumentation.

Topics: Cross Reactions; Enzyme-Linked Immunosorbent Assay; Food Contamination; Humans; Infant; Infant Formula; Reproducibility of Results; Sensitivity and Specificity; Triazines; Triticum

A hydrophilic interaction liquid chromatography coupled to ESI-MS (HILIC/ESI-MS) method for the simultaneous determination of melamine and related compounds, i.e. ammeline, ammelide and cyanuric acid in foods was developed and validated. The separation was accomplished on a Venusil HILIC column with a mobile phase of acetonitrile + 10 mM ammonium formate buffer solution at pH 3.5 (88:12, v/v) under isocratic elution mode. For the detection of the targets, the ESI probe worked in the positive and negative switching mode. For each compound, three ions were selected as qualitative ions to obtain high specificity, and the most abundant ion of each compound was selected for quantification to obtain high sensitivity. The target compounds were quantified using SIM with 15N3-melamine and 13C3-cyanuric acid being used as an internal standards in the positive and negative modes, respectively. Compared with RP separation mode, HILIC has merits such as high separation and anti-interference efficiency. The method validation including linearity, LOD, LOQ, precision and recovery proved that the method has merits such high sensitivity, specificity and simplicity versus the other methods reported in the literature.

Topics: Buffers; Chromatography, Liquid; Molecular Structure; Reproducibility of Results; Sensitivity and Specificity; Spectrometry, Mass, Electrospray Ionization; Triazines

A method was developed for the simultaneous determination of melamine, ammeline, ammelide, and cyanuric acid in egg using gas chromatography-tandem mass spectrometry (GC-MS/MS). The samples were first extracted by the solution of diethylamine-water-acetonitrile (10:40:50, v/v/v). Clean-up employed an 'On Guard II' RP cartridge, and the dried elute was derivatised using bis-(trimethylsilyl)trifluoroacetamide (BSTFA) with 1% trimethylchlorosilane (TMCS). Derivatised samples were analysed by GC-MS/MS using multiple-reaction monitoring (MRM) with (13)C(3)-(15)N(3)-labelled melamine and cyanuric acid as internal standards. Blank samples of egg were spiked with the four analytes at concentration level of 0.1, 0.5, 1.0 mg kg(-1), and the intra-day and inter-day recoveries were in the range 75.7-122.5% with the relative standard deviation (RSD) from 2.6% to 22.8%. Decision limits (CCα, α = 0.01) for melamine, ammeline, ammelide, and cyanuric acid in egg samples and milk powder were 3.5-5.9 and 2.5 to 3.8 µg kg(-1), and the detection capabilities (CCβ, β = 0.05) were 4.9-8.4 and 3.6-9.5 µg kg(-1), respectively. The method was successfully applied to egg samples and milk products as well. Satisfactory results were obtained as part of the 2009 European Union melamine proficiency test.

Topics: Analytic Sample Preparation Methods; Animals; Calibration; Chickens; Dairy Products; Eggs; Food Contamination; Food Inspection; Gas Chromatography-Mass Spectrometry; Indicators and Reagents; Limit of Detection; Radioisotope Dilution Technique; Reproducibility of Results; Tandem Mass Spectrometry; Triazines; Trimethylsilyl Compounds

Two kinds of online preconcentration techniques including large-volume sample stacking-sweeping and selective-exhaustive injection-sweeping (SEI-S) were employed in CE to develop a rapid, simple and sensitive method for determination of melamine (MM) and its derivatives such as ammeline (AMN), ammelide (AMD) and cyanuric acid (CA) in liquid milk products. Though the sensitivity of large-volume sample stacking-sweeping is not particularly high, it can be used to detect all the four compounds simultaneously. However, it is very difficult to improve the sensitivity of these four compounds by using single SEI-S method directly, owing to their completely different extents of protonation or deprotonation. Grouping can solve this problem perfectly. After the four compounds are divided into two groups (MM/AMN and AMD/CA), cation-SEI-S or anion-SEI-S can be applied for their online stacking. In cation-SEI-S, the detection limits for MM and AMN were both 0.01 ng/mL based on the signal-to-noise ratio of 3. In anion-SEI-S, the detection limits were 0.05 and 0.02 ng/mL for CA and AMD, respectively. Results of this study show a great potential for the SEI-S method to be a useful tool for the rapid and sensitive determination of MM and its derivatives in liquid milk products.

Topics: Animals; Chemical Fractionation; Electrophoresis, Capillary; Milk; Regression Analysis; Sensitivity and Specificity; Triazines

To develop an analytical method for simultaneously qualitative and quantitative determination of melamine and triazine-related by-products including ammelide, ammeline, and cyanuric acid in milk and milk products by gas chromatography-tandem mass spectrometry (GC-MS/MS).. Melamine and triazine-related by-products namely ammelide, ammeline and cyanuric acid in the samples were extracted in a solvent mixture of diethylamine, water, and acetonitrile (10:40:50, V/V/V). After centrifugation, an aliquot of the supernatant was evaporated to dryness under a gentle stream of nitrogen gas, and then melamine and triazine-related by-products were derivatized using BSTFA with 1% TMCS. The derivatives of melamine and its analogues were determined by gas chromatography/tandem mass spectrometry using multiple reactional monitoring (MRM) with 2, 6-Diamino-4-chloropyrimidine (DACP) being used as an internal standard.. The linear detectable ranges were from 0.004 mg/kg to 1.6 mg/kg for melamine, ammelide, ammeline, and cyanuric acid with a correlation coefficient no less than 0.999. The recovery rates of the four compounds in spiked blank milk powder at concentrations 0.5, 1, 2 mg/kg were between 61.4%-117.2%, and the relative standard deviation was no more than 11.5% (n=6). The detection limits of melamine, ammelide, ammeline and cyanuric acid in milk powder were 0.002 mg/kg with a ratio of signal to noise of 3.. This GC-MS/MS method for simultaneous determination of melamine, ammelide, ammeline, and cyanuric acid in milk and milk products is sensitive and specific.

Topics: Animals; Cattle; Chromatography, Gas; Flame Retardants; Food Contamination; Milk; Molecular Sequence Data; Sensitivity and Specificity; Tandem Mass Spectrometry; Triazines

Melamine has been used for the adulteration of cereal flours in order to increase their apparent protein content. Crude melamine may contain several by-products, i.e. ammeline, ammelide, and cyanuric acid. The simultaneous analysis of all four chemicals is difficult because of the formation of an insoluble salt between melamine and cyanuric acid. A simple and convenient high-performance liquid chromatography (HPLC) method for the detection of the adulteration of cereal flours with all four chemicals is proposed herein. The precipitate formation between melamine and cyanuric acid was prevented by using alkaline conditions (pH 11-12) for both standards preparation and sample extraction. The method uses matrix-matching, which involves the construction of a calibration curve on a blank (negative control) matrix, which is then used for the quantitation of melamine and by-products in adulterated (positive) samples. Matrix-matching compensates for analyte losses during sample preparation, and for matrix effects. The method was successfully applied to wheat, corn, and rice flours, and is expected to be applicable (with some modifications) to soy flour as well. The method allows for the detection of melamine, ammeline, and ammelide at approximately 5 microg g(-1), and cyanuric acid at approximately 90 microg g(-1) in wheat flour.

Topics: Chromatography, High Pressure Liquid; Edible Grain; Flour; Food Contamination; Triazines