高效液相色谱法测定2-氨基-3-硝基苯甲酰胺的研究

通过对液相色谱条件的优化,获得最佳分离条件,建立了2-氨基-3-硝基苯甲酰胺的高效液相色谱测定方法。即以甲醇和0.2%乙酸铵溶液为流动相,PDA检测器,检测波长为216 nm,流速0.5 mL/min,柱温25℃。在此条件下,2-氨基-3-硝基苯甲酰胺能够得到很好的分离。在0.3~1.5 g/L质量浓度和6×10~(-4)~6×10~(-3)mg质量范围内都呈良好的线性关系。方法的精密度、准确度较高。     

建立一种新型六氯环三磷腈的分析方法

建立了反相高效液相色谱外标法测定合成聚磷腈高聚物的原料六氯环三磷腈的含量。样品用乙腈溶解,过滤,采用SynergiHydro-RP分析柱（250 mm×4.6 mm,4μm）,以保留时间作为定性依据。在建立的色谱条件下,杂质能得到很好的分离,线性范围为4.704×10-7~1.47×10-3g.mL-1,方法的线性相关系数为0.99999,平均回收率101.1%,相对标准偏差（RSD）2.1%,该方法具有简便、灵敏、重复性好等优点,适于对六氯环三磷腈快速鉴定分析。     

4%吡丙醚·氟虫腈微囊悬浮-悬浮剂的高效液相色谱分析方法

建立一种同时分析吡丙醚和氟虫腈的高效液相色谱法。采用Shim-pack VP-ODS C18色谱柱和紫外-可见检测器,以乙腈+水为流动相,在278 nm波长下对4%吡丙醚·氟虫腈微囊悬浮-悬浮剂进行分离和定量分析。吡丙醚和氟虫腈的线性相关系数均为0.999 9,标准偏差均为0.01,变异系数分别为0.87%、0.32%,平均回收率分别为100.02%、99.57%。结果表明,高效液相色谱方法灵敏、快速,适用于4%吡丙醚·氟虫腈微囊悬浮-悬浮剂的含量检测。     

160g/L氟虫脲+100g/L氟虫腈悬浮剂的高效液相色谱检测

采用高效液相色谱法测定农药复合制剂160 g/L氟虫脲+100 g/L氟虫腈悬浮剂。选用C_(18)反相色谱柱(150 mm×4.6 mm i.d,5μm),以乙腈+甲醇+水(体积比为42+36+22)为流动相,用紫外检测器在260 nm波长下,对试样中的氟虫脲和氟虫腈进行分离和定量检测。氟虫脲、氟虫腈的平均回收率分别为100.3%和99.5%,相对标准偏差分别为0.61%和0.25%。     

乙虫腈中间体5-氨基-3-氰基-4-乙硫基-1-(2,6-二氯-4-三氟甲基苯基)吡唑的液相色谱分析

5-氨基-3-氰基-4-乙硫基-1-(2,6-二氯-4-三氟甲基苯基)吡唑是杀虫剂乙虫腈的重要中间体。采用液相色谱法对其含量分析方法进行了研究。采用甲醇和水为流动相,选用HypersilC18色谱柱,紫外检测器进行分析。结果显示标准偏差为0.38,变异系数0.40%,回收率为99.5%,线性相关系数为0.999。在建立的分析条件下,测定5-氨基-3-氰基-4-乙硫基-1-(2,6-二氯-4-三氟甲基苯基)吡唑的有效成分的方法具有较好的线性、精密度和准确度,是较理想的分析方法,完全能够满足工业化对5-氨基-3-氰基-4-乙硫基-1-(2,6-二氯-4-三氟甲基苯基)吡唑的质量控制。     

QuEChERS-高效液相色谱-串联质谱法测定蜜蜂及蜂产品中5种农药及氟虫腈代谢物残留

[目的]建立蜜蜂及蜂蜜和蜂花粉中氟虫腈、氟甲腈、氟虫腈硫醚、氟虫腈砜、灭幼脲、氟啶脲、氟铃脲、杀铃脲等5种农药及氟虫腈代谢物的QuEChERS-高效液相色谱-串联质谱分析方法(HPLC-MS/MS),并将该方法用于实际样品检测。[方法]样品中的农药残留用乙腈提取,盐析后用C18、PSA吸附剂净化,经C18色谱柱分离,在电喷雾离子源(ESI-),多反应监测模式(MRM)下分析,外标法定量。[结果]方法的线性范围为0.1～100μg/L,相关系数均≥0.999,定量限为1～10μg/kg (S/N=10);在1～50μg/kg范围内的添加回收率为76.2%～117.9%,相对标准偏差≤22.5%。[结论]该方法简单、快速、灵敏、稳定,适合蜜蜂和蜂产品中5种农药及氟虫腈代谢物的检测。     

氟虫腈在B-Z化学振荡体系中的分析检测

在封闭体系中研究了氟虫腈对别洛索夫-扎鲍京斯基(B-Z)化学振荡体系的扰动,结果表明氟虫腈的加入明显的改变了振荡体系的振幅,氟虫腈的浓度在2.5×10-5～1.25×10-7 mol/L范围内与振荡体系振幅的变化值ΔA呈现良好的线性关系,相关系数为0.9976,最低检出限为1.0×10-8 mol/L以此建立了测定氟虫腈的快速、简单、灵敏的新方法。     

农药氟虫腈的高效液相色谱检测

采用Lichrospher C18色谱柱(4.6 mm×150 mm,5μm),以乙腈+甲醇+水(40+34+26)为流动相,流速1.0 m L/min,检测波长280 nm,建立高效液相法(HPLC)测定微量氟虫腈浓度。结果表明:在0.2153~0.9524 mg/L(约21.53~95.24 ppm)具有较好的线性关系,其线性关系为y=28218x-818.7、r=0.9991,并用喷洒过氟虫腈的白菜样品验证了该线性关系。     

溴虫腈的高效液相色谱分析

采用高效液相色谱法,使用紫外检测器,以（甲醇＋水）为流动相,在C18柱上对溴虫腈进行高效液相色谱分离和测定。     

食品中氟虫腈残留量的检测方法研究进展

对食品中氟虫腈的分析检测方法进行了综述,对氟虫腈检测前处理过程使用的提取试剂乙腈、丙酮、乙酸乙酯、正己烷-丙酮(2∶1,V/V)的适用性做了评述,并对固相萃取小柱和洗脱试剂做了简要介绍和比较;最后详细介绍了氟虫腈的仪器分析方法,包括气相色谱法、气相色谱-质谱联用法、液相色谱法、液相色谱-质谱联用法等。     

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.     

Many Drugs of Abuse May Be Acutely Transformed to Dopamine,Norepinephrine and Epinephrine In Vivo

It is well established that a wide range of drugs of abuse acutely boost the signaling of the sympathetic nervous system and the hypothalamic–pituitary–adrenal (HPA) axis, where norepinephrine and epinephrine are major output molecules. This stimulatory effect is accompanied by such symptoms as elevated heart rate and blood pressure, more rapid breathing, increased body temperature and sweating, and pupillary dilation, as well as the intoxicating or euphoric subjective properties of the drug. While many drugs of abuse are thought to achieve their intoxicating effects by modulating the monoaminergic neurotransmitter systems (i.e., serotonin, norepinephrine, dopamine) by binding to these receptors or otherwise affecting their synaptic signaling, this paper puts forth the hypothesis that many of these drugs are actually acutely converted to catecholamines (dopamine, norepinephrine, epinephrine) in vivo, in addition to transformation to their known metabolites. In this manner, a range of stimulants, opioids, and psychedelics (as well as alcohol) may partially achieve their intoxicating properties, as well as side effects, due to this putative transformation to catecholamines. If this hypothesis is correct, it would alter our understanding of the basic biosynthetic pathways for generating these important signaling molecules, while also modifying our view of the neural substrates underlying substance abuse and dependence, including psychological stress-induced relapse. Importantly, there is a direct way to test the overarching hypothesis: administer (either centrally or peripherally) stable isotope versions of these drugs to model organisms such as rodents (or even to humans) and then use liquid chromatography-mass spectrometry to determine if the labeled drug is converted to labeled catecholamines in brain, blood plasma, or urine samples.     

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.