高效液相色谱法检测食品接触产品中的三聚氰胺及其衍生物的迁移量

建立了高效液相色谱同时检测三聚氰胺(MEL)及其衍生物——三聚氰酸二酰胺(ANE)、三聚氰酸一酰胺(ADE)和三聚氰酸(CYA)单体迁移量的方法.样品分别采用水、4％乙酸、10％乙醇作为食品模拟物,在70℃浸泡4h,浸泡液过0.45μm微孔薄膜后进入色谱柱.色谱分离采用Luna NH2柱,柱温:30℃,流动相为V(乙腈...     

三聚氰酸钴配合物的合成、晶体结构及荧光性质

本文合成了一个新的配合物Co(H2CA)2(H2O)2(H3CA=三聚氰酸),并通过元素分析、红外、荧光和单晶X-Ray射线进行了表征。标题化合物属于三斜晶系,P1空间群,a=0.503 83(7)nm,b=0.699 82(10)nm,c=0.911 08(13)nm,α=90.107(2)°,β=98.032(2)°,γ=110.788(2)°,V=0.296 92(7)nm3,Z=1,R=0.038 2。在配合物中,Co(Ⅱ)离子与三聚氰酸配体上的N原子,配位水的O原子配位,形成规则的平面正方形配位构型。相邻的2个Co(Ⅱ)平面四边形单元通过配体三聚氰酸上的氢键形成三维网状结构。室温荧光光谱测定表明该化合物在420 nm处有强的荧光发射。     

固相萃取-亲水相互作用色谱/串联质谱法同时测定食品中三聚氰胺和三聚氰酸

建立了固相萃取-亲水相互作用色谱/串联质谱同时测定食品中三聚氰胺和三聚氰酸残留量的方法。采用乙腈和水提取试样中残留的三聚氰胺和三聚氰酸,正己烷脱脂,提取液经亲水性键合硅胶和阳离子交换树脂复合填料柱(MCT柱)净化。采用亲水相互作用色谱柱进行分离,质谱采用正、负离子切换模式电离,多反应监测模式检测,同位素内标法定量。三聚氰胺和三聚氰酸在10～2500 μg/L范围内呈线性相关,相关系数(r)均大于0.99,定量限分别为25和50 μg/kg。本方法在动物源性食品、植物源性食品、乳及乳制品等不同样品中的三聚氰胺和三聚氰酸高、中、低3个添加水平的回收率分别在70.0%～129.6%和70.0%～128.6%之间,相对标准偏差分别在1.4%～23.3%和2.8%～18.7%之间。该方法可满足食品中三聚氰胺和三聚氰酸同时定量测定的需要。     

水介质中双(1,4-二氢吡啶)衍生物的合成

水介质中在苄基三乙基氯化铵(TEBAC)催化下,利用对苯二甲醛与1,3-二羰基化合物及醋酸铵的多组分反应合成了一系列官能团化双(1,4-二氢吡啶)衍生物。产物的结构通过红外光谱和核磁共振氢谱确定.该方法具有操作简单、产率高、环境友好等特点,为新型1,4-二氢吡啶衍生物的合成提供了一条绿色合成的途径。     

亲水作用色谱-串联质谱法同时测定液态奶中三聚氰酸和三聚氰胺

建立了亲水作用色谱-串联质谱同时测定液态奶中三聚氰酸和三聚氰胺的方法。液态奶样品经体积分数2.5%甲酸溶液提取、离心后乙腈稀释,亲水作用色谱柱分离,电喷雾串联四极杆质谱检测器检测,分别在负、正离子模式下测定三聚氰酸和三聚氰胺。三聚氰酸和三聚氰胺分别在0.5～100μg/L、0.1～50μg/L范围内线性关系良好。在0.25～15mg/kg、0.1～7.5mg/kg添加水平范围内,三聚氰酸平均回收率为84.5%～98.0%(RSD为2.1%～6.1%),三聚氰胺平均回收率为85.5%～88.9%(RSD为3.2～5.8%)。三聚氰酸、三聚氰胺定量限分别为0.25mg/kg、0.1mg/kg。     

应用亲水作用色谱检测鸡蛋和肉中三聚氰胺及三聚氰酸二酰胺

应用亲水作用色谱(HILIC)对从市场上购买的鸡蛋和肉中的三聚氰胺及三聚氰胺降解产物三聚氰酸二酰胺进行了检测。采用的色谱柱为ZIC-HILIC柱,流动相为3 mmol/L磷酸二氢铵溶液(pH 6.9)-乙腈(20:80, v/v),流速为0.8 mL/min,检测波长为220 nm。在该体系下,三聚氰胺和三聚氰酸二酰胺的保留时间适中,与样品中的内源性物质有良好的分离。样品经0.1%磷酸提取,偏磷酸及乙腈沉淀蛋白质和糖类物质,以及P-SCX固相萃取柱净化。三聚氰胺和三聚氰酸二酰胺在0.4～40 mg/L范围内与峰面积呈良好的线性关系,样品定量限(按信噪比(S/N)不小于10计)为2 mg/kg,在2～10 mg/kg添加水平下的平均回收率为80%～105%,相对标准偏差小于10%。该方法具有良好的分离选择性,可用于鸡蛋和肉中三聚氰胺和三聚氰酸二酰胺的同时检测。     

反相高效液相色谱法同时分析三聚氰酸和三聚氰胺

建立了同时分析三聚氰酸和三聚氰胺的反相高效液相色谱法．发现三聚氰酸和三聚氰胺在C8柱上的保留比在C18柱上明显要强,这一结果表明三聚氰酸和三聚氰胺在反相固定相中的保留并非以通常的疏水分配作用为主导．方法的紫外检测下限为0．034～0．31mg／L,标准曲线线性范围为0．5-100mg／L．方法不经特殊的样品前处理即可用于奶粉和游泳池水等样品中三聚氰酸和三聚氰胺的同时分析．     

气相色谱-质谱法快速测定牛奶中的三聚氰胺和三聚氰酸

建立了气相色谱-质谱法测定牛奶中三聚氰胺和三聚氰酸含量的分析方法。样品经二乙胺-乙腈-水溶液超声提取,离心,滤液用氮气吹干后加入硅烷化衍生试剂衍生,气相色谱-质谱测定,选择离子模式监测,外标法定量。在0.025～2 mg/kg范围内,目标物的峰面积与其质量浓度的线性关系良好(r>0.98);在0.5,1.0和2.5 mg/kg的添加水平,三聚氰胺和三聚氰酸的平均回收率分别为84%～87%和75%～102%,相对标准偏差(RSD)分别为5.7%～11.7%和4.9%～7.8%;三聚氰胺和三聚氰酸的检出限(LOD)分别为0.05 mg/kg和0.10 mg/kg。结果表明:该方法简便、快速、灵敏、准确,适合牛奶中三聚氰胺和三聚氰酸的确证和定量测定。     

新型介孔二氧化硅囊泡结构的调变

本文采用水热合成法,利用非离子表面活性剂聚环氧乙烷-聚环氧丙烷-聚环氧乙烷(P123)对有机溶剂均三甲苯(TMB)的增容作用,合成了大孔径介孔二氧化硅囊泡材料,首次通过控制有机溶剂TMB与无机硅源正硅酸四乙酯(TEOS)的投料时间间隔t,实现对介孔二氧化硅囊泡材料结构的调变。通过小角X射线衍射和高分辨透射电镜(HTEM)检测技术对酸性P123模板体系中的材料结构转变过程进行了表征。结果表明,改变TMB与TEOS的投料时间间隔,能够实现介孔囊泡结构的调变,同时提出"协同囊泡模板"(cooperative vesicle templating,CVT)和"协同作用机制"(cooperative formation mechanism,FM)共存。通过简单合理的设计合成不同结构的介孔材料,以期开拓其在催化、分离以及医学等领域的潜在应用,也为合成其他介孔材料提供简单合理的设计思路。     

亲水色谱-串联质谱法对牛奶与奶粉中三聚氰胺及其衍生物含量的测定

建立了牛奶和奶粉中三聚氰胺及其3种衍生物（三聚氰酸、三聚氰酸一酰胺、三聚氰酸二酰胺）的亲水色谱-串联质谱检测方法（HILIC-MS/MS）。牛奶样品直接用乙腈超声波提取;奶粉样品先用水溶解后再加乙腈超声波提取,高速离心后以乙腈-水为流动相,采用亲水作用色谱柱分离这4种化合物,在电喷雾正、负电离切换多反应监测模式下进行定性与定量分析,三聚氰酸一酰胺与三聚氰酸二酰胺含量在50～10000μg/kg之间、三聚氰胺与三聚氰酸在25～5000μg/kg之间,均获得良好的线性。方法检出限（LOD）为5～20μg/kg,定量下限（LOQ）为50～100μg/kg,3个添加水平的平均回收率为81%～97%。该方法简便、快速、准确,可满足牛奶及奶粉中三聚氰胺、三聚氰酸、三聚氰酸一酰胺、三聚氰酸二酰胺测定的需要。     

柱后氨化-超高效液相色谱-串联质谱法测定牛奶和奶粉中的三聚氰酸

建立了一种柱后氨化-超高效液相色谱-串联质谱法(UPLC-MS/MS)测定牛奶和奶粉中三聚氰酸的分析方法。样品用5%三氯乙酸溶液提取,无需净化和浓缩,用Acquity UPLC HSS T3色谱柱(50 mm×2.1 mm, 1.8 μm)进行分离,以乙腈和水作为流动相进行梯度洗脱,柱后氨化,电喷雾负离子(ESI~)模式电离,多反应监测(MRM)模式进行检测。结果表明: 三聚氰酸在10.0～160.0 μg/L范围内线性关系良好(r≥0.99)。牛奶在0.05、0.10、0.20 mg/kg的添加浓度的回收率为60%～118.5%,相对标准偏差(RSD, n=6)为8.2%～12.6%;奶粉在0.25、0.50、1.00 mg/kg的添加浓度的回收率为88%～108%, RSD(n=6)为2.5%～5.7%。牛奶中方法的定量限(信噪比为10)为0.05 mg/kg,奶粉中为0.25 mg/kg。该方法快速、灵敏、准确,适合于牛奶、奶粉等乳及乳制品中三聚氰酸的快速、高灵敏度的分析检测。     

A simple and expedient method for the stepwise synthesis of 2-ethoxy-(4H)-3,1-benzoxazine-4-ones

A simple and practical route is described for the synthesis of 2-efhoxy-(4H)-3,1 -benzoxazine-4-ones using the coupling reaction of anthranilic acid derivatives with diethyl dicarbonate following with fast cyclization of the carbamate adduct with a dehydrocyclization agent such as cyanuric chloride and N,N′-dicyclohexylcarbodiimide in PEG at room temperature.High yields of the products obtained under mild reaction conditions with simple work-up of the reaction mixture.     

Fast quantitative determination of melamine and its derivatives by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

A simple, sensitive and fast method for the determination of melamine and its derivatives in milk powder using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) was developed. Neither time-consuming sample preparation, nor special target plates, or other extra equipment are necessary. The common matrix sinapinic acid (SA) was used with a dried-droplet preparation. Detection limits (signal-to-noise (S/N) ratio = 3) for standard solutions of melamine, ammeline and cyanuric acid were 10, 25 and 10 μg/L, respectively. The limit of quantification (LOQ) for melamine was 25 μg/L and excellent linearity (R(2): 0.9990) was maintained over the range of 10-2000 μg/L. Ammeline and cyanuric acid were analyzed with an LOQ of 50 μg/L and also excellent linearity (R(2): 0.9997 and R(2): 0.9998). Good accuracy and precision were obtained for all concentrations within the range of the standard curve. The developed method was successfully used for the determination of melamine, ammeline and cyanuric acid in milk powder samples with a simple sample preparation. The LOQ of melamine was 0.5 μg/g. Ammeline and cyanuric acid were detectable at 0.5 and 5 μg/g. This method showed excellent accuracy, precision and linearity and significantly reduces the needed analysis time, as only approximately 10 s/sample measuring time is required. To the authors' knowledge, this is the first published method to quantify melamine and derivatives by MALDI-TOF-MS.     

One-pot synthesis of oxygen and nitrogen-bridged calix[2]arene[2]triazines

A simple and powerful one-pot reaction method was developed for the synthesis of heteracalixaromatics. In the presence of a base, one-pot macrocyclic condensation reaction between cyanuric chloride and 1,3-phenylene diols and diamines proceeded effectively under very mild conditions to afford a number of functionalised oxygen and nitrogen-bridged calix[2]arene[2]triazines in 33–54% yields. The method was applied in a multigram-scale (14.4 g) preparation of tetraoxacalix[2]arene[2]triazine.     

Determination of melamine and cyanuric acid in powdered milk using injection-port derivatization and gas chromatography–tandem mass spectrometry with furan chemical ionization

A reliable, sensitive and eco-friendly injection-port trimethylsilylated (TMS) derivatization and gas chromatography–tandem mass spectrometry (GC–MS/MS) with furan chemical ionization (furan-CI) method was developed to determine melamine and cyanuric acid in powdered milk samples. The effects of several parameters related to the TMS-derivatization process (i.e., injection-port temperature, residence time and volume of silylating agent) and of various CI agents were investigated. Addition of a solution (3 μL) of bis(trimethyl)silyltrifluoroacetamide (BSTFA) containing 1% trimethylchlorosilane (TMCS) reagent to a 20-μL extract from the powdered milk sample gave an excellent yield of the tris-TMS-derivatives of melamine and cyanuric acid at an injection-port temperature of 90 °C. Furthermore, using furan as the CI agent in conjunction with tandem mass spectrometry provided the greatest sensitivity and selectivity of detection. The limits of quantitation (LOQs) for melamine and cyanuric acid were 0.5 and 1.0 ng/g in 0.5-g of powdered milk samples, respectively. The recoveries from spiked samples – after simple ultra-sonication with 5% dimethyl sulfoxide in acetonitrile coupled with n-hexane liquid–liquid extraction – ranged from 72% to 93% with relative standard deviations of lower than or equal to 18%. In three of four real powdered milk samples, melamine was detected at concentrations ranging from 36 to 1460 ng/g; and cyanuric acid was detected in two of these samples at concentrations of 17 and 180 ng/g.     

One-pot three-component synthesis of α-amino nitriles catalyzed by nano powder TiO_2 P 25

A simple and efficient method has been developed for the synthesis ofα-amino nitriles from aldehydes,amines and trimethylsilyl cyanide（Me₃SiCN） in the presence of a catalytic amount of cyanuric acid at room temperature.     

混合型固相萃取柱净化-气相色谱-质谱法测定婴幼儿配方奶粉中的三聚氰酸

建立了一种混合型固相萃取柱净化-气相色谱-质谱法(GC-MS)测定婴幼儿配方奶粉中三聚氰酸的方法。在84 ℃条件下,用0.5%乙酸水溶液提取样品中的三聚氰酸,离心,滤液经Carb/C18混合型固相萃取柱净化,氮气吹干,硅烷化衍生,GC-MS测定,选择离子监测模式,外标法定量。在0.01～2 mg/L内线性关系良好(r＞0.99),在0.25～2.5 mg/kg的添加水平范围内,平均回收率为80%～103%,相对标准偏差(RSD)为7.7%～14.5%,三聚氰酸的检出限(LOD)为0.10 mg/kg,定量限(LOQ)为0.25 mg/kg。该方法快速、灵敏、准确、专一、耐用,适合婴幼儿配方奶粉中三聚氰酸的确证和定量测定。     

Stable association complex electrospray mass spectrometry for the determination of cyanuric acid

Cyanuric acid, a suspected gastrointestinal or liver toxicant, has gained interest as a potential degradation product of triazine herbicides, such as simazine and atrazine. This paper investigates the determination of cyanuric acid by stable association complex electrospray mass spectrometry (cESI-MS). The cyanuric acid is extracted from the water through a microscale liquid-liquid extraction. The extract is evaporated to dryness, and an aqueous solution of quaternary ammonium cationic surfactant is added. When injected into the electrospray mass spectrometer, the surfactant and the cyanuric acid form a mass-selective stable association complex, which may be used for confident quantification of cyanuric acid. Several extraction solvents and surfactants were investigated. These studies provide insight into the mechanism of electrospray for the formation of these complexes, specifically with regard to the surface activity of the different surfactants and the chemistry of the surfactant-cyanuric acid complexes. From an analytical standpoint, the cESI-MS method detection limit for extraction of a 1 mL aqueous solution of cyanuric acid was 130 microg/L based on 3.14sigma(n-1) of seven replicate injections. Standard additions were used for quantification of eight aqueous samples. The cyanuric acid concentrations determined with cESI-MS were not significantly different at the 95% confidence level to those determined by conventional high-performance liquid chromatography (HPLC). A recovery of 100% from a fortified urine sample illustrates the robustness of the technique.