Simultaneous Determination of Melamine, Ammelide, Ammeline, and Cyanuric Acid in Milk and Milk Products by Gas Chromatography-tandem Mass Spectrometry

Objective 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）. Methods 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. Results 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 tour 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. Conclusion This GC-MS/MS method for simultaneous determination of melamine, ammelide, ammeline, and cyanuric acid in milk and milk products is sensitive and specific.

Induction of Apoptosis in the Immature Mouse Testes by a Mixture of Melamine and Cyanuric Acid

The toxicity of melamine has attracted much attention since the recent outbreaks of renal injury in pets and infants. Previous studies indicated that melamine by itself had low toxicity, whereas a mixture of melamine and cyanuric acid （M＋CA） could cause serious renal damage. At present, most researches on the toxicity of M＋CA are focused on the kidney. However, little is known about the adverse effects of this mixture on the reproductive system. In the present study, the toxicity of M＋CA to testes was investigated. Immature male mice were orally dosed with 0, 0.6, 3, and 15 mg kg-1 d-1 of a 1：1 M＋CA for 28 d. Pathological changes occurred in germ cells, such as loose arrangement, reduced numbers and karyopyknosis, indicating that this mixture was toxic to spermatogenesis. Compared with the control group, the TUNEL- positive germ cells increased significantly and the ratio of Bcl-2 to Bax, total antioxidant capacity and superoxide dismutase activity decreased significantly in the 3 and 15 mg kg-1 d- M＋CA treated group, while the activities of caspase-3, caspase- 8 and caspase-9 remained unchanged. The results suggest that M＋CA can induce apoptosis in the mice testes. The downregulation of Bcl-2/Bax and oxidative stress may play a pivotal role in the induction of apoptosis by M＋CA in mice testes.

Crystal Structure of Calcium Complex with Cyanuric Acid Ligand［Ca（C3H3N3O3－O）（H2O）6］［（OH）（C3H2N3O3）］

ＣｒｙｓｔａｌＳｔｒｕｃｔｕｒｅｏｆＣａｌｃｉｕｍＣｏｍｐｌｅｘｗｉｔｈＣｙａｎｕｒｉｃＡｃｉｄＬｉｇａｎｄ［Ｃａ（Ｃ３Ｈ３Ｎ３Ｏ３－Ｏ）（Ｈ２Ｏ）６］［（ＯＨ）（Ｃ３Ｈ２Ｎ３Ｏ３）］ＬｉｎＺｈｏｕ－Ｂｉｎ；ＣｈｅｎＣｈａｎｇ－Ｚｈａｎｇ；...

Research Progress on Detection Methods of Melamine and Cyanuric Acid Residue in Dairy Products and Feedstuff

[Objective] More accurate, rapid and sensitive method of melamine and cyanuricacid residue in dairy products and feedstuff were re- viewed. [ Method] Physicochemical properties, metabolism, uses, harm and detection methods of melamine and cyanuric acid were analyzed and described. [ Result] Melamine and cyanuric acid, when used alone, were slightly toxic, but long -term intake could lead to animal reproductive and urinary system damage. [ Condusion] Establishing a more sensitive, fast and easy to popularize detection method for elarnine and cyanuricacid res- idue in dairy products and feedstuff was necessary.

An Evaluation of Genotoxicity and Cytotoxicity of Melamine in Combination with Cyanuric Acid at Three Mass Ratios

Melamine in combination with cyanuric acid has been considered to be more toxic than either melamine or cyanuric acid alone. The objective of this study was designed to evaluate the combined genotoxicity and cytotoxicity of melamine （M） and cyanuric acid （C） at three mass ratios （1：1, 1：2, 2：1）. MC （1：1）, MC （1：2）, and MC （2：1） were evaluated for their potential genotoxic risk, at gene level by Ames test, and at chromosomal level by micronucleus test. In order to evaluate cytotoxicity in HEK-293 cells, the MTT assay was included. Western blot was also employed to investigate the renal injury molecule-1 （Kim-1） expression in HEK-293 cells exposed to MC. Neither genotoxicity at gene level nor at chromosomal level was observed for MC （1：1）, MC （1：2）, and MC （2：1）. Based on MTT assay, three ratios of MC at 82.5 and 165 μg/mL slightly inhibited viability of HEK-293 cells （P〈0.05）. MC （1：1） at 41.25 and 82.50 IJg/mL could elevate the Kim-1 expression in HEK-293 cells.

Biodegradation of Melamine and Cyanuric Acid by a Newly-Isolated <i>Microbacterium</i>Strain

We searched for a superior melamine-degrading bacterium for the bioremediation of melamine. Cyanuric acid, which is a by-product produced during the biodegradation of melamine, shows strong nephrotoxicity. Therefore, the melamine-degrading bacterium is also required to show a high ability to degrade cyanuric acid. We selected a melamine-degrading strain (MEL1) among ten cyanuric acid-degrading bacteria isolated from the soil. The species of MEL1 strain was Microbacterium esteramaticum or was extremely similar to that species, and the enzymatic activity of the melamine deaminase in the MEL1 strain was similar to that in the NRRLB-12227 strain. The ability of the MEL1 strain to degrade cyanuric acid was higher than its ability to degrade melamine, and therefore, the accumulation of by-products (ammeline, ammelide and cyanuric acid) during the degradation of melamine was minimal. These results suggest that the MEL1 strain is useful for the bioremediation of melamine.

Synthesis and Surface Active Properties of Cyanuric Chloride-based Branched Surfactant

A series of novel branched sodium carboxylate surfactants were synthesized from cyanuric chloride, behera amine, alcohol amine and 1,4-Bis (3-aminopropyl) piperazine through seven steps, and the total yield is about 25%. The chemical structures of target products were confirmed by 1H NMR, 13C NMR, FT-IR and ESI-MS. Their critical micelle concentrations (CMC) were also determined by surface tension tests in the aqueous solutions at 22 ℃. The results showed that the CMC value of multi-carboxylate anionic surfactants decreased with the increase of hydroxyl. Additionally, the branched structure of end group can reduce surface tension more than straight-chain type, which was determined by γCMC. The decomposition temperature of the target compound was 250 ℃, which was also tested by TG/DTA curve.

A facile synthesis of novel optically active R,R-2-(4-(2-(4-(5-chloro-3-halo-pyridin-2-yloxy)-phenoxy)-propionyloxy)-phenoxy)-propionic acid esters using cyanuric chloride as potential herbicide

A facile method for the synthesis of a new series of R,R-2-（4-（2-（4-（5-chloro-3-halopyridin-2-yloxy）-phenoxy）-propionyloxy）-phenoxy） -propionic acid ester derivatives containing a halo-substituted pyridine carrying two R,R chiral centers from（R）-2-（4- hydroxyphenoxy）propionic acid,halopyridines and alcohols using base/cyanuric chloride/catalyst system is reported.Their herbicidal activities against grass weeds and crops selectivity were evaluated.

Enhanced Crystallization Rate of Biodegradable Poly(ε-caprolactone) by Cyanuric Acid as an Efficient Nucleating Agent

The influence of cyanuric acid（CA） as an efficient nucleating agent on the crystallization behavior and morphology of biodegradable poly（ε-caprolactone）（PCL） was extensively studied in this work with several techniques for the first time. The nonisothermal melt crystallization behavior and overall isothermal melt crystallization rate of PCL were significantly enhanced by only a small amount of CA. The addition of CA apparently improved the nonisothermal melt crystallization peak temperature, overall isothermal melt crystallization rate, and nucleation density of PCL spherulites, but did not modify the crystallization mechanism and crystal structure of PCL, indicating that CA was an efficient nucleating agent for the crystallization of PCL. The possible nucleation mechanism of CA on the crystallization of PCL was also discussed on the basis of their crystal structures.

Facile Synthesis of Dendritic Hydroxyl-terminated Cyanuric Chloride Derivatives and Their Properties

Novel dendritic compounds G1.5（OH）4 and G1.5（OH）8 with peripheral hydroxyl were synthesized under mild conditions from eyanuric chloride, ethylene diamine, ethanolamine and diethanolamine. The products could be separated and purified through dispersion and precipitation in organic solvents with good yields （over 93.0%） and high purity （above 98.0%, HPLC）. The structures of the products were characterized by 1R, MS, 1H NMR and elementary analysis. G1.5（OH）4 and Gl.5（OH）8 could be dissolved in polar solvents such as methanol, water and dimethylsulfoxide. TGA analysis showed that G1.5（OH）4 and G1.5（OH）8 had good thermo stability. The aqueous solutions ofG1.5（OH）4 and G1.5（OH）8 exhibited low surface tension.

A Two-coordinate Copper（Ⅰ） Complex Constructed from Cyanuric Acid and 4,4＇-Bipyridyl： Synthesis, Structure and Photoluminescence

A two-coordinate copper（Ⅰ） complex, Cu2（bipy）（H2L）2 （1） （H3L=cyanuric acid, bipy=4,4＇-bipyridyl）, which exhibits strong photoluminescence, has been synthesized under hydrothermal conditions and structurally characterized by single crystal X-ray diffraction. The compound crystallizes in the monoclinic space group P21/n, with cell parameters： Mr= 539.42, a= 13.4806（5）A↑°, b=4.5234（2） A↑°, c= 15.4952（8）A↑°,β = 105.526（3）°, V=910.39（7）A↑°^3, Z=2 and μ=3.52 mm^ -1. In the structure the two Cu（Ⅰ） ions are bridged by bipy to form a two-coordinate copper（Ⅰ） dimer. The adjacent dimer units are connected by hydrogen bonding interactions, resulting in 1D zigzag chains along the c axis. 1 emits intense yellow light when excited with UV light.

The contribution of mediated oxidation mechanisms in the electrolytic degradation of cyanuric acid using diamond anodes

In this work, the contribution of mediated oxidation mechanisms in the electrolytic degradation of cyanuric acid using boron-doped diamond（BDD） anodes was investigated in different electrolytes. A complete mineralization of cyanuric acid was obtained in Na Cl;however lower degrees of mineralization of 70% and 40% were obtained in Na2SO4 and Na Cl O4, respectively. This can be explained by the nature of the oxidants electrogenerated in each electrolyte. It is clear that the contribution of active chlorine（Cl2, HCl O, Cl O-）electrogenerated from oxidation of chlorides on BDD is much more important in the electrolytic degradation of cyanuric acid than the persulfate and hydroxyl radicals produced by electro-oxidation of sulfate and water on BDD anodes. This could be explained by the high affinity of active chlorine towards nitrogen compounds. No organic intermediates were detected during the electrolytic degradation of cyanuric acid in any the electrolytes, which can be explained by their immediate depletion by hydroxyl radicals produced on the BDD surface. Nitrates and ammonium were the final products of electrolytic degradation of cyanuric acid on BDD anodes in all electrolytes. In addition, small amounts of chloramines were formed in the chloride medium. Low current density（≤ 10 m A/cm2） and neutral medium（p H in the range 6–9） should be used for high efficiency electrolytic degradation and negligible formation of hazardous chlorate and perchlorate.

宠物食品中三聚氰胺及三聚氰酸的液相色谱串联质谱法分析

A rapid and sensitive LC-MS/MS method was established to analyze melamine and cyanuric acid in pet food and its ingredients.HILIC mechanism was utilized to separate small highly polar compounds such as melamine and cyanuric acid.In comparison with US FDA recognized GCMS and LC methods,it turned out that the current technique is superior with easy sample preparation,and the sensitivity and selectivity was found satisfactory.The LOD was 50 ng·L-1 for melamine and 1 μg·L-1 for cyanuric acid,respectively.

A Survey on Occurrence of Melamine and Its Analogues in Tainted Infant Formula in China

Objective To investigate the occurrence and concentrations of melamine and its analogues in tainted infant formula and to identify the etiologic factors for the urinary stones epidemic in infants and young children in China in 2008. Methods Sanlu infant formula samples were collected from families of the affected children in Gansu province, and markets in Gansu and Hebei provinces and Beijing city. Melamine and its analogues, including cyanuric acid, ammeline, and ammelide were measured by gas chromatography/tandem mass spectrometry. Results High prevalence and concentrations of melamine were found in Sanlu infant formula samples, with low concentrations of cyanuric acid, ammeline and ammelide. Melamine were detected in 87 out of 111 Sanlu infant formula samples with a range of 118 to 4 700 mg/kg, Conclusion The results provide strong evidence for melamine as the etiological factor for the urinary stones epidemic in infants and young children in China in 2008.

Investigations on the Degradation of Triazine Herbicides in Water by Photo-Fenton Process

In this work, the degradation of 2-chloro-4,6-diamino-1,3,5-triazine in aqueous solutions by photo-Fenton process has been investigated. The preliminary results have shown that the degradation of 2-chloro-4,6-diamino-1,3,5-triazine by photo-Fenton process is more rapid and more effective than Fenton and UV/H2O2 processes. The effects of certain experimental parameters on kinetics and efficiency of the degradation of 2-chloro-4,6,-diamino-1,3,5-triazine by photo-Fenton process, have been evaluated. Under optimal conditions, photo-Fenton process achieved more than 90% of chloride release and about 30% of nitrate formation. The results of total organic carbon (TOC) and total Kjeldahl nitrogen (TKN) analyses have shown that no carbon dioxide and ammonia are formed during photo-Fenton treatment of aqueous solutions containing 40 mg/L triazine. These results indicate that only substituent groups of triazine ring are released;however, nitrogen atoms of triazine ring remain unaffected. A simple mechanism of degradation of 2-chloro-4,6-diamino-1,3,5-triazine has been proposed. The degradation starts by a rapid release of chlorine atoms as chloride ions to form 2-hydroxy-4,6-diamino-1,3,5-triazine. The amino groups of 2-hydroxy-4,6-diamino-1,3,5-triazine undergo are oxidized into nitro groups by hydroxyl radicals to form 2-hydroxy-4,6-dinitro-1,3,5-triazine which undergoes a slow release of nitro groups and their substitution with hydroxyl groups to form cyanuric acid and nitrate ions. The degradation of cyanuric acid by photo-Fenton process has also been investigated. The results of TOC and TKN analyzes show that no carbon dioxide is formed during the treatment.

A 100% Water Mobile Phase HPLC-PDA Analysis of Meamine and Related Analogues

This paper describes a reserved-phase high performance liquid chromatographic method for detecting melamine (MEL) and related analogues, cyanuric acid (CYA), ammeline (AML), and ammelide (AMD), using a 100% water mobile phase. Chromatographic separation was performed an Inertsil? ODS-4 (250 × 4.6 mm, 5 μm) with a water mobile phase and a photodiode-array detector. The monitoring wavelength was adjusted to 210 nm which represents an average maximum for all the analytes. The total run time was < 8 min. The method shows high stability, significant linearity and satisfactory sensitivity. The detection limits were established in the range 23 - 46 ng.mL–1. An inexpensive and harmless method for the simultaneous detection of MEL, CYA, AML, and AMD was developed and may be further applied to the quantification in foods.

Antimicrobial M aterials: Synthesis of Reactive 5,5-Dimethylhydantoin Derivative and Application in Cellulose with Dyeing Process

The efficient and regenerable antibacterial properties of Nhalamines make them an ideal candidate for parapretion of antimicrobial textiles. In this study,a 5,5-dimethylhydantoin-based reactive N-halamine precursor, 4-( 4-( 3-( 3-hydroxypropyl)-5,5-dimethylhydantoin)-6-chloro-1,3,5-triazinylamino)-benzenesulfonate( HTB), was synthesized and characterized by ~1H-NMR. The synthesized compound was coated to cotton fabrics via reactive dye dyeing process. The coated cotton showed excellent antimicrobial activities against S. aureus( Gram-positive) and E. coli O157: H7( Gram-negative) with short contact times after exposing to diluted household bleach. The treatment method used in this study has a small effect on the tensile strength of cotton fabrics. The durability and regenerability of the chlorinated cotton samples were tested.Although the chlorine content decreased towards washing and storage,almost all of the initial oxidative chlorine levels could be regained after rechlorination.

Synthesis of a Fluorophore with Improved Optical Brightness

The synthesis and characterization of a novel fluorophore(1), with potential application as an optical brightener are reported. This compound was prepared by reacting 4,4-diaminostilbene-2,2-disulfonic acid with cyanuric chloride in the presence of Na2CO3 followed by the addition of trityl aniline. Solution and solid state fluorescence demonstrated a strong blue/purple emission centered at 450 nm. 1H-NMR spectroscopy, mass spectrometry analysis, elemental analysis, and DOSY-NMR were used for the characterization of the fluorophore.

Flame retardant polyamide 6 by in situ polymerization of ε-caprolactam in the presence of melamine derivatives

An improved method for preparing melamine cyanurate （MCA） based flame retardant polyamide 6 （FRPA6） materials has been proposed. This processing method, i.e., improved in situ polymerization, was used to synthesize flame retardant PA6. In situ formed MCA nanoparticles were supposed to be linked to PA6 chains in the ε-caprolactam hydrolytic polymerization system to obtain startype polymers for the first time. Through TEM photographs, it can be found that the in situ formed MCA nanoparticles with diametric size of less than 50 nm, are nanoscaled, highly uniformly dispersed in the PA6 matrix. Synthesized flame retardant PA6 have good fire performance which can achieve UL-94 V-0 rating at 1.6 mm thickness with the presence of 7.34 wt.% MCA in the matrix.

Formation of Hybrid Ring Structure of Cyanurate/Isocyanurate in the Reaction be-tween 2,4,6-Tris(4-Phenyl-Phenoxy)-1, 3,5-Triazine and Phenyl Glycidyl Ether

Reaction products of 2,4,6-tris(4-phenyl-phenoxy)-1,3,5-triazine derived from 4-phenylphenol cyanate ester and phenyl glycidyl ether were analyzed. In addition to an isocyanurate compound and an oxazolidone compound which were well known as reaction products of cyanate esters and epoxy resins, compounds with hybrid ring structure of cyanurate/isocyanurate were determined. Gibbs free energies of the compound having hybrid ring structure of cyanurate/isocyanurate with two isocyanurate moiety were found to be lower than that of the compound with cyanurate ring structure through calculations. Calculation data supported the existence of hybrid ring structure of cy-anurate/isocyanurate. It was revealed that isomerization from cyanurate to isocyanurate occurs via hybrid ring structure of cyanurate/isocyanurate in the reaction of aryl cyanurate and epoxy.