胶体金层析免疫法对盐酸克伦特罗的检测试验

盐酸克伦特罗俗称"瘦肉精",若大量添加到猪饲料中,将在猪肉及内脏中残留,给食品安全带来了隐患。传统的检测技术繁琐,成本高,不利于推广普及。本实验利用胶体金层析法检测盐酸克伦特罗,结果表明:最低检测限度为5 ppb,具有简便、便捷、快速、灵敏度强的特点。     

安捷伦推出高精度猪肉中“瘦肉精”残留检测方法

随着"瘦肉精"猪肉事件的再次曝光,国家各部门立即派出督察组督导查处工作。安捷伦对该事件立即做出反应,推出了具有高精度猪肉中"瘦肉精"超痕量分析的解决方案。瘦肉精是     

毛细管气相色谱法测定酱腌菜中的对羟基苯甲酸酯类含量

利用GC-FID技术,对酱腌菜样品中的防腐剂对羟基苯甲酸乙酯、丙酯检测进行了方法建立及实际样品测试。分析结果表明,该方法对酱腌菜中对羟基苯甲酸乙酯、丙酯检测的相对标准偏差为1.8%～5.0%,样品的回收率为88%～97%。方法准确可靠、快速。     

试纸法在食品及水质检测领域的应用

在食品和水质检测领域,利用试纸法能够在现场完成污染物的快速检测。基于这种情况,对试纸法进行了分析,并且对该方法在食品检测和水质检测中的应用情况展开了探讨,从而为关注这一话题的人们提供参考。     

液质联用快速测定果冻中的甜蜜素

利用液质联用建立检测果冻中甜蜜素的快速分析方法,该方法在0.01-10μg/mL范围内线性良好(r=0.9991),回收率在95.6%-99.7%之间,重复性较好,相较传统方法,该方法样品处理简单、快速、准确,适合于果冻中甜蜜素快速检测。     

高频红外碳硫仪测定碳素结构钢中碳硫

利用CS-8800C型高频红外碳硫仪研究了测定碳素结构钢中碳硫的方法。通过改变分析时间、样品加入量并结合碳硫释放曲线,确定最佳分析条件,该方法快速准确,满足检测需求。     

汽油中MTBE的傅里叶红外光谱分析方法研究

傅里叶红外光谱技术由于检测限低,灵敏度高,快速测定、选择性好等优点,被广泛应用于油品质量检测中。本文利用该方法研究了MTBE的红外光谱特性,在校正集浓度范围(0.6%～20%)内,浓度与吸光度呈现较好的线性关系,其线性相关系数为0.999 27,检测限为0.12%,并结合经典最小二乘法预测了汽油样品中MTBE的含量,结果显示,该方法准确、方便,能够满足汽油中MTBE含量快速检测的要求。     

高效液相色谱法测定牛肉中伊维菌素残留量

采用高效液相色谱法,利用荧光检测器检测,建立了牛肉中伊维菌素残留的检测方法。该法简单快速,灵敏度高,准确性好。     

分光光度法快速测定ABC灭火剂中的磷酸二氢铵和硫酸铵含量

为了满足消防产品中灭火剂的现场快速检测需求,提出利用钼锑抗分光光度法和纳氏试剂分光光度法快速测定ABC灭火剂中主要组分磷酸二氢铵和硫酸铵含量的新方法。与现行国家标准方法相比,该方法具有快速、简便、准确的优点,适合灭火剂产品的现场快速检测。     

王水微波消解测定污水处理厂污泥中重金属

介绍了王水微波消解-原子吸收光谱法测定污水处理厂污泥中六种金属元素(Cu、Zn、Ni、Cr、Pb、Cd)的一种方法。利用该方法对标准土壤样品进行了测定分析,回收率为86%～103%,相对标准偏差(RSD)为1.4%～6.7%,结果表明,该方法简便、快速、实用,具有较好的精密度和准确度。同时,该方法在青浦区六家污水处理厂污泥中重金属含量检测分析中也取得了良好的应用,得到了令人满意的结果。     

Insect antifeedant properties of anthranoids from the genusVismia

Vismiones and ferruginins, representatives of a new class of lypophilic anthranoids from the genusVismia were found to inhibit feeding in larvae of species ofSpodoptera, Heliothis, and inLocusta migratoria.     

Direct observation of freeze-thaw instability of latex coatings via high pressure freezing and cryogenic SEM

Despite its industrial importance, the subject of freeze-thaw (F/T) stability of latex coatings has not been studied extensively. There is also a lack of fundamental understanding about the process and the mechanisms through which a coating becomes destabilized. High pressure (2100 bar) freezing fixes the state of water-suspended particles of polymer binder and inorganic pigments without the growth of ice crystals during freezing that produce artifacts in direct imaging scanning electron microscopy (SEM) of fracture surfaces of frozen coatings. We show that by incorporating copolymerizable functional monomers, it is possible to achieve F/T stability in polymer latexes and in low-VOC paints, as judged by the microstructures revealed by the cryogenic SEM technique. Particle coalescence as well as pigment segregation in F/T unstable systems are visualized. In order to achieve F/T stability in paints, latex particles must not flocculate and should provide protection to inorganic pigment and extender particles. Because of the unique capabilities of the cryogenic SEM, we are able to separate the effects of freezing and thawing, and study the influence of the rate of freezing and thawing on F/T stability. Destabilization can be caused by either freezing or thawing. A slow freezing process is more detrimental to F/T stability than a fast freezing process; the latter actually preserves suspension stability during freezing. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004 in Chicago, IL. Tied for first place in The John A. Gordon Best Paper Competition.     

Ethanol and (−)-α-Pinene: Attractant Kairomones for Bark and Ambrosia Beetles in the Southeastern US

In 2002–2004, we examined the flight responses of 49 species of native and exotic bark and ambrosia beetles (Coleoptera: Scolytidae and Platypodidae) to traps baited with ethanol and/or (−)-α-pinene in the southeastern US. Eight field trials were conducted in mature pine stands in Alabama, Florida, Georgia, North Carolina, and South Carolina. Funnel traps baited with ethanol lures (release rate, about 0.6 g/day at 25–28°C) were attractive to ten species of ambrosia beetles (Ambrosiodmus tachygraphus, Anisandrus sayi, Dryoxylon onoharaensum, Monarthrum mali, Xyleborinus saxesenii, Xyleborus affinis, Xyleborus ferrugineus, Xylosandrus compactus, Xylosandrus crassiusculus, and Xylosandrus germanus) and two species of bark beetles (Cryptocarenus heveae and Hypothenemus sp.). Traps baited with (−)-α-pinene lures (release rate, 2–6 g/day at 25–28°C) were attractive to five bark beetle species (Dendroctonus terebrans, Hylastes porculus, Hylastes salebrosus, Hylastes tenuis, and Ips grandicollis) and one platypodid ambrosia beetle species (Myoplatypus flavicornis). Ethanol enhanced responses of some species (Xyleborus pubescens, H. porculus, H. salebrosus, H. tenuis, and Pityophthorus cariniceps) to traps baited with (−)-α-pinene in some locations. (−)-α-Pinene interrupted the response of some ambrosia beetle species to traps baited with ethanol, but only the response of D. onoharaensum was interrupted consistently at most locations. Of 23 species of ambrosia beetles captured in our field trials, nine were exotic and accounted for 70–97% of total catches of ambrosia beetles. Our results provide support for the continued use of separate traps baited with ethanol alone and ethanol with (−)-α-pinene to detect and monitor common bark and ambrosia beetles from the southeastern region of the US.     

Novel polyurethane coating technology through glycidyl carbamate chemistry

Glycidyl carbamate chemistry combines the excellent properties of polyurethanes with the crosslinking chemistry of epoxy resins. Glycidyl carbamate functional oligomers were synthesized by the reaction of polyfunctional isocyanate oligomers and glycidol. The oligomers were formulated into coatings with several amine functional crosslinkers at varying stoichiometric ratios and cured at different temperatures. Properties such as solvent resistance, hardness, and impact resistance were dependent on the composition and cure conditions. Most coatings had an excellent combination of properties. Studies were carried out to determine the kinetics of the curing reaction of the glycidyl carbamate functional oligomers with multifunctional and model amines. Detailed kinetic analysis of the curing reactions was also undertaken. The results indicated that the glycidyl carbamate functional group is more reactive than a glycidyl ether group. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, on October 27–29, 2004, in Chicago, IL.     

Highly moisture-proof polysilsesquioxane coating prepared via facile sol-gel process

A highly moisture-proof polysilsesquioxane coating was obtained from a new bis-silylated precursor, which was synthesized from 3-aminopropyltriethoxysilane (APTES) and m-xylylene diisocyanate (m-XDI) in tetrahydrofuran (THF) and verified by ¹H MAS NMR. For direct comparison purposes, an SiO₂ coating was also prepared by the Stöber method using tetraethoxysilane (TEOS) as the reactant. Interestingly, the coating obtained from the polysilsesquioxane sol exhibited a much higher moisture resistance capability than its counterpart, which was attributed to its more compact feature between nanoparticles as characterized by N₂ absorption experiment and transmission electron microscopy (TEM). Furthermore, its high transparency of about 92% showed potential for application in the protection of optical crystals.