cDNA基因芯片技术分析三聚氰胺肾毒性的相关基因表达

利用基因芯片技术筛查不同剂量的三聚氰胺干预大鼠肾脏的差异表达基因, 并对筛查的差异基因进行生物信息学分析, 推测三聚氰胺肾毒性的分子作用机制. 结果表明, 高剂量三聚氰胺干预的大鼠肾脏差异表达基因数多于低剂量干预的肾脏差异表达基因, 并且涉及到更多重要的分子功能和代谢途径, 表明三聚氰胺肾毒性具有剂量依赖性, 相比低剂量而言, 高剂量三聚氰胺干预对肾脏的危害更为严重.     

高效液相色谱法测定宠物食品中的三聚氰胺

建立了测定宠物食品中三聚氰胺的高效液相色谱分析方法。采用ODS分离柱,以10.0 mmol/L的庚烷磺酸钠(用HCl调节pH 3.0)-乙腈(90∶10)为流动相,在236 nm波长下检测三聚氰胺含量,测定结果的平均回收率为96.5%,平均相对标准偏差为1.39%。最低定量检出浓度为2 mg/kg。本方法也可应用于其它类型动物食品中三聚氰胺的含量分析。     

荧光光谱法测定奶制品中的三聚氰胺

三聚氰胺能够与荧光素在水溶液中发生作用,使荧光素的荧光强度增强,且在一定浓度范围内,荧光强度与三聚氰胺的浓度成线性关系,据此建立了一种新的测定奶制品中三聚氰胺的荧光分析方法。方法的回归方程为ΔI=178.2ρ(10-6g/L),r=0.9977,线性范围5.00×10-7~1.00×10-5g/L,RSD为1.9%(n=10),检出限为9.85×10-8g/L。采用该方法测定奶粉和液态奶中三聚氰胺的含量,测得的平均回收率分别为95.1%和95.8%。     

超高速液相色谱测定奶粉中的三聚氰胺

使用超高速液相色谱仪(LCU),在LaChromUltra C18柱(50×2.0 mm i.d.,2 μm)上,以10 mol/L柠檬酸-10 mol/L辛烷磺酸钠/CH3CN为流动相,紫外240 nm检测,2.2 min内快速检测出奶粉中的三聚氰胺.结果表明,三聚氰胺浓度在0.25～100 μg/mL范围内线性关系良好(R2>0.999),平均回收率为87%～95%,保留时间的相对标准偏差为0.26%～0.38%,峰面积的相对标准偏差为0.91%～1.82%.该方法适用于大批量样品的常规分析.     

食品中的假蛋白——三聚氰胺

自2008年6月起,我国甘肃等地陆续报告多例婴幼儿患泌尿系统结石的病例。经调查后发现,这些患儿多有食用三鹿牌婴幼儿配方奶粉的历史。石家庄三鹿集团公司则于9月11日发表声明,经自检发现部分批次三鹿婴幼儿奶粉受到三聚氰胺污染,公司决定立即全部召回2008年8月6日以前生产的三鹿婴幼儿奶粉。在随后开展的全国范围内婴幼儿配方奶粉三聚氰胺的专项检查中发现,有22家企业69批次产品检出了含量不同的三聚氰胺。     

UPLC-MRM法测定饲料中的三聚氰胺

提出了一种UPLC-MRM测定饲料中微量三聚氰胺的分析方法. 饲料经10 g/L三氯乙酸溶液提取和22 g/L乙酸铅溶液沉淀蛋白质, 过混合型阳离子交换柱(MCX)纯化, 离心后用0.45 μm滤膜过滤, 用超高效液相色谱-质谱-质谱联用仪(UPLC-MS-MS)分析测定, 以三聚氰胺母离子126.9 (m/z)和子离子67.5与84.6 (m/z)定性、定量目标物. 饲料样品加标回收率(n=6)为84.5%, 检测限0.01 μg/L, 相对偏差(RSD) 6.5%.     

高效液相色谱法测定鸭肉中的三聚氰胺

采用反相高效液相色谱法测定了鸭肉中的三聚氰胺.Diamonsil C18柱,流动相:V(乙腈)∶V(4 mmol/L己烷磺酸钠水溶液)=5∶95,乙酸调pH为3.3;检测波长240 nm.在0.25～40 mg/L范围内线性关系良好,相关系数R=0.9999.方法检出限0.056 mg/kg,回收率在80%～86%之间,相对标准偏差小于2.55%.     

化学发光法测定奶粉中的三聚氰胺

在碱性条件下,三聚氰胺对鲁米诺-铁氰化钾体系化学发光反应具有明显的增敏作用;据此建立了流动注射化学发光测定奶粉中三聚氰胺的分析方法,确定了优化测定条件,并将该方法用于测定奶粉中的三聚氰胺.结果表明,在优化测定条件下,三聚氰胺的质量浓度在1.0×10-6～4.0×10-5 g.L-1范围内与发光强度呈现良好的线性关系,检出限为2.6×10-7 g.L-1,11次平行测定4.0×10-6 g.L-1三聚氰胺的相对标准偏差为3.42%.与此同时,将所建立的方法用于奶粉中三聚氰胺的测定,结果令人满意.     

液相色谱法测定大豆分离蛋白中的三聚氰胺

建立了大豆分离蛋白中三聚氰胺的液相色谱方法。大豆分离蛋白经过1%三氯乙酸和饱和乙酸铅溶液提取后,经过阳离子交换固相萃取柱净化处理,用5%氨化甲醇洗脱,洗脱液用高效液相色谱紫外检测器检测,外标法定量。三聚氢胺的质量浓度在0.4~40 mg/L范围内与色谱峰面积呈良好的线性关系,相关系数为0.9990。方法的检出限为0.6 mg/kg,定量限为2 mg/kg。2,4,20 mg/kg 3个浓度水平的加标回收率在78.82%~92.95%范围内。该方法分析成本低,测定结果准确,能满足常规检测及食品安全监控的需要。     

同位素内标法测定乳品中的三聚氰胺

本文以自制的15 N3-三聚氰胺作为内标,建立了测定乳制品中的三聚氰胺残留量的高效液相色谱-串联质谱(HPLC-MS/MS)分析方法。方法的线性范围为1～1 000ng/mL,回收率为95.6%～98.7%,相对标准偏差(RSD)为1.3%～2.5%,检出限(S/N=3)为1ng/mL。该方法灵敏度高,准确性好,为三聚氰胺的检测提供了一种可靠实用的方法。     

液相色谱串联质谱法(LC-MS/MS)分析宠物食品中三聚氰胺

三聚氰胺(melamine)为白色或无色结晶,通常用于塑料制品中合成树脂的生产中,高温和酸性条件下能引起三聚氰胺转移到食品中.三嗪类农药环丙氨嗪(cyromazine)在极端的pH条件下或者光降解的条件下也能生成三聚氰胺.     

Melamine and Cyanuric Acid in Foodstuffs and Pet Food: Method Validation and Sample Screening

Hazardous levels of melamine in food and feed products have been of great concern after the outbreak of contamination reported in Chinese commodities in 2008. Despite the existence of several analytical methods for melamine (MEL) detection in food, few provide a full validation data set, especially when MEL and cyanuric acid (CYA) are analyzed simultaneously. The aim of this study was to validate an analytical methodology for MEL and CYA analysis in foodstuffs by GC-MS after trimethylsilylation with N,O-bis(trimethylsilyl)trifluoroacetamide. Linearity was obtained in the range of 0.4 to 800 mg/kg for both compounds, with limits of detection (LODs) of 0.15 and 0.05 mg/kg for MEL and CYA, respectively. Screening in 20 food products [3 soya milk powder, 1 baby milk powder, 3 soya powder, 13 diversified cookies and biscuits (8 from China and 2 from Portugal), and 3 dog food) revealed MEL incidence in 55% of the cases, with a maximum concentration of 3.4 mg/kg. CYA was not detected in all samples.     

高热稳定性三聚氰胺聚磷酸盐的合成

以三聚氰胺和磷酸为原料,以去离子水为溶剂,在杂多酸A催化下,制得改性三聚氰胺磷酸盐(MP);将MP在箱式气氛炉中进行多温度段热缩合反应合成了三聚氰胺聚磷酸盐(MPP),其结构经~(31)P NMR,IR和元素分析表征。通过TG对MPP的热稳定性和成炭性能进行了分析。结果表明:MPP失重1%时温度为372.1℃,失重5%时温度为382.7℃,700℃时残炭率为37.36%。     

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

三聚氰胺(Melamine)为白色或无色结晶,常用于合成树脂的生产.三嗪类农药环丙氨嗪(Cyromazine)在极端的pH条件下或者光降解的条件下也能生成三聚氰胺.近来,不法厂商将三聚氰胺添加到宠物食品中引起宠物死亡的事件,得到广泛关注.因此,如何快速准确地分析食品中的三聚氰胺成为食品企业、食品监管机构和广大民众密切关注的问题.     

三聚氰胺三聚硫氰酸盐的合成

以三聚氰胺和三聚硫氰酸为原料合成了一种新型含硫三聚氰胺基阻燃剂——三聚氰胺三聚硫氰酸盐(MSA),其结构和热性能经1H NMR,13C NMR,FT-IR,元素分析和TGA表征。确定了合成MSA的最优工艺条件为:去离子水为溶剂,三聚硫氰酸和三聚氰胺摩尔比为1∶1,反应时间为3 h。TGA分析表明:MSA失重5%时,温度为308.8℃,600℃时分解基本完全,残碳率为0.86%。     

Determination of Melamine in Dairy Products and Melamine Tableware by Inhibition Electrochemiluminescent Method

An electrochemiluminescent (ECL) method has been developed for the determination of melamine based on the inhibition of luminol ECL. A significant luminol ECL can be found at 1.47 V in the phosphate buffer solution at high pHs and low potential scan rates, this ECL signal can be inhibited obviously by melamine. The decrease of ECL intensity was linearly proportional to the logarithm of melamine concentration in the range of 1–100 ng/mL (R²=0.9911) and with the detection limit of 0.1 ng/mL. The method has been applied successfully to determine melamine in dairy products and melamine tableware, the recoveries were in the range of 98.5%–103.7% and 95.5%–106.0%, respectively. The mechanism of the inhibition effect was also proposed, the active oxygen (O₂^{· −}) generated from the electrooxidation of OH⁻ reacted with luminol anion (L^{· −}) to generate light emission, and the present of melamine can eliminate the active oxygen, which cause the decrease of the ECL intensity.     

固相萃取与高效液相色谱联用测定宠物食品中三聚氰胺

1引言三聚氰胺(m elam ine)为白色或无色结晶,通常用于塑料制品中合成树脂的生产,在高温和酸性条件下能引起三聚氰胺转移到食品中。近来,一些不法厂商将三聚氰胺添加到宠物食品中导致宠物死亡,引起广泛关注。因此,如何快速、准确地分析食品中的三聚氰胺成为食品企业,食品监管机     

气相色谱-质谱法测定鸡蛋中三聚氰胺

建立了气相色谱-质谱法测定鸡蛋中三聚氰胺的方法. 鸡蛋样品经三氯乙酸提取,乙酸铅沉淀蛋白后,过MCX阳离子交换固相萃取小柱除去样品基质干扰,用N,O-双三甲基硅基三氟乙酰胺(BSTFA)+三甲基氯硅烷(TMCS)(99+1)衍生,进行气相色谱-质谱分析. 在0.010~2.00 mg/L浓度范围内,线性关系良好(r=0.9996),检出限为0.01 mg/kg. 方法回收率为90.1%~94.7%,RSD为1.7%~5.3%. 方法准确、灵敏,适用于鸡蛋中三聚氰胺的检测.     

Surfactants Used in Food Industry: A Review

The understanding of the formation, structures, and properties of emulsions is essential to the creation and stabilization of structures in food. The increasing use of surfactants, the identification of compounds with low toxicity and good surface activity properties is of great interest. The relevance of the major end points specified in the Organisation for Economic Co-operation and Development (OECD) guidelines for the hazard assessment of food chemicals is critically analyzed and main parameters are acute toxicity, subacute repeated studies, allergy, reproductive toxicity, long-term studies, and mutagenicity tests. We focus this article on surfactant association structures and food colloids. There is almost infinite number of combinations are organized and arranged in very complex internal microstructures with various types of assemblies such as dispersions, emulsions, foams, gels, etc. Low-mass surfactants are very mobile at the interface and they are particularly efficient reducing the interfacial tension. As a result, they rapidly coat the freshly created oil-water interface during emulsification. In this category, we mainly mentioned monoglycerides, lecithins, glycolipids, fatty alcohols and fatty acids. High-mass surfactants cover protein and polysacharide groups. The protein molecule may interpenetrate in the lipid phase to various degrees. The specific binding is predominantly electrostatic: The headgroups of the surfactants bind to groups of opposite charge on the protein. The saturation binding for anionic surfactants is pH-independent and seems to be controlled by the cooperative hydrophobic interactions. Polysaccharides and smallmolecule surfactants are two of the predominant groups of amphiphilic materials that have been explored for the stabilization of emulsions. One of the most important aspects of polymer-surfactant systems is their ability to control stability and rheology over a wide range of composition. Biocompatible, biodegradable, and/or nontoxic emulsion-based formulations have great potential for applications in the food. The combination of particular characteristics such as emulsifying, anti-adhesive and antimicrobial activities presented by biosurfactants suggests potential application as multipurpose ingredients or additives.