SPE-UPLC-Q-TOF/MS测定水环境中的雌激素

研究建立了固相萃取、超高效液相色谱-四极杆串联飞行时间质谱(UPLC-Q-TOF/MS)测定水环境中6种雌激素(雌三醇、雌二醇、炔雌醇、雌酮、己烯雌酚、双酚A)的分析方法。水样经甲醇活化后的C18固相萃取小柱富集浓缩,用10 mL 10%的甲醇溶液淋洗,10 mL纯甲醇洗脱,洗脱液经高纯氮气吹至0.4 mL后用UPLC-Q-TOF/MS测定。6种常见的雌激素质量浓度在0.5~100μg/L范围内时,具有良好的线性(R0.993 7),检出限介于5.60~10.6 ng/L之间。空白加标水样为1μg/L的水平下,相对标准偏差(RSD)为2.8%~9.0%,其加标回收率为75%~101%。该方法可用于水体中雌激素的分析测定。     

凝固分散液液微萃取-HPLC法测定水中萘芴菲

建立了凝固分散液液微萃取(SFO-DLLME)-高效液相色谱法(HPLC)测定水中萘、芴和菲的新方法。以1-十二醇为萃取剂,甲醇为分散剂,优化了影响SFO-DLLME萃取效率的因素。在最佳条件下,萘、芴和菲的检出限分别为0.011、0.056、0.049μg/L,萘的线性范围为0.1~50.0μg/L,芴和菲的线性范围为1.0~500μg/L。实际水样加标回收率78.6%~95.1%,相对标准偏差(n=5)3.9%~7.2%。方法简便快速,灵敏度高,环境友好,成功用于实际水样分析。     

分散液液微萃取-分光光度法测定水中痕量铜

以氯仿为萃取剂,乙腈为分散剂,新铜试剂为螯合剂,建立了水中痕量铜分散液液微萃取分光光度法测定的新方法。研究了萃取剂、分散剂、络合剂的用量、p H、萃取时间等影响因素。在最佳条件下,方法的线性范围为1.0~200μg/L,相关系数(r)为0.998 4,检出限为0.35μg/L,对100μg/L的铜离子进行11次平行测定的相对标准偏差为3.42%,加标回收率为96.2%~101.7%。方法可应用于水样中痕量铜含量的测定。     

全自动固相萃取-气相色谱/质谱法测定水中的甲萘威

[目的]建立了全自动固相萃取-气相色谱/质谱联用测定水体中甲萘威的方法。[方法]优化了固相萃取的条件,采用ProElut PLS固相萃取柱,以甲醇作为洗脱溶剂萃取水样中的甲萘威,用气相色谱/质谱法测定。[结果]甲萘威质量浓度在5.0~250.0μg/L范围内与其气相色谱/质谱响应值线性关系良好,相关系数为0.9999,检出限为0.022μg/L。样品加标回收率在90.2%~92.5%之间,测定结果的相对标准偏差为1.9%~3.2%。[结论]该方法自动化程度高、快速、准确,适合于水中甲萘威的测定。     

分散液液微萃取-分光光度法测定水中痕量铜

以氯仿为萃取剂,乙腈为分散剂,新铜试剂为螯合剂,建立了水中痕量铜分散液液微萃取分光光度法测定的新方法。研究了萃取剂、分散剂、络合剂的用量、p H、萃取时间等影响因素。在最佳条件下,方法的线性范围为1.0²00μg/L,相关系数(r)为0.998 4,检出限为0.35μg/L,对100μg/L的铜离子进行11次平行测定的相对标准偏差为3.42%,加标回收率为96.2%200μg/L,相关系数(r)为0.998 4,检出限为0.35μg/L,对100μg/L的铜离子进行11次平行测定的相对标准偏差为3.42%,加标回收率为96.2%¹01.7%。方法可应用于水样中痕量铜含量的测定。     

磁性固相萃取-高效液相色谱串联三重四级杆质谱法测定环境水样中的磺胺类抗生素残留

建立了磁性固相萃取-高效液相色谱串联三重四级杆质谱法分析环境水样中的磺胺类抗生素残留的方法。优化后的磁性固相萃取条件:将50 mg磁性萃取材料加入100 m L水样,调节水样pH至4,振荡萃取20 min后利用外加磁场收集磁性萃取材料,再用4 m L甲醇(含1%氨水)涡旋洗脱,分离洗脱液氮吹至干,用液相色谱初始流动相定容后进行高效液相色谱-串联质谱分析。4种磺胺类抗生素在5~500μg/L范围内线性良好,相关系数均大于0.999,检出限为4.2~4.7μg/L,加标回收率为72.3%~88.5%,相对标准偏差在3.5%~10.2%之间。该方法简单便捷、用时短、重现性好、有机试剂消耗少,能够应用于实际水样中磺胺类抗生素的检测。     

浊点萃取分光光度法测定水样中痕量铁

建立了浊点萃取-分光光度法测定痕量铁的新方法。详细考察了溶液的pH值、螯合剂和表面活性剂浓度、平衡温度和时间等条件对浊点萃取效果的影响。该方法的线性范围为6.0~500μg/L(r=0.9996),检出限为1.58μg/L,加标回收率为98.7%~101.6%,相对标准偏差为1.3%~2.2%。该方法已成功应用于实际水样分析。     

分散固相萃取-UHPLC-MS/MS法测定水中5种苯脲类除草剂

建立分散固相萃取-超高液相色谱串联质谱(UHPLC-MS/MS)同时测定环境水样中5种苯脲类除草剂(敌草隆、利谷隆、灭草隆、异丙隆、绿麦隆)残留的分析方法。考察了吸附剂的种类与数量、水样pH、吸附剂的种类和体积等条件对除草剂回收率的影响。在最佳实验条件下,5种苯脲类除草剂在0.01~5.0μg/L范围内呈良好的线性关系(0.999 3~0.9999),方法检出限为2.04~3.12 ng/L。对环境水样的加标回收率分别为78.2%~108.3%,相对标准偏差RSD分别为6.8%~11.2%。本方法操作简便快速、稳定性好、灵敏度高,能够满足环境水体中苯脲类除草剂残留的分析要求。     

同步荧光法测定河水中的多环芳烃

建立了竹炭固相萃取恒能量同步荧光法测定河水中多环芳烃(PAHs)。优化了实验条件。选定正己烷为洗脱溶剂,洗脱溶剂体积为10 m L,上样速率为5 m L/min,上样体积为555 m L。该方法的检出限在0.185~1.77 ng·m L~(-1)之间,相对标准偏差为2.28%~5.40%,实际水样的加标回收率为95.4%~110.7%。     

悬浮固化分散液液微萃取光度法测定痕量锌

采用悬浮固化分散液液微萃取(DLLME-SFO)分光光度法测定水样中痕量锌。以1-(2-吡啶偶氮)-2-萘酚(PAN)为配位剂,密度小于水,凝固点为24℃的十二醇为萃取剂,乙醇为分散剂,对水样进行分散液液微萃取。对萃取剂和分散剂的类型和体积、溶液的p H、PAN的用量、萃取时间等参数进行了优化。方法的线性范围5.0~800μg/L,检出限0.62μg/L,富集倍数50倍,应用于测定水样中痕量锌,回收率为96%~98.7%。     

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.     

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.     

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.     

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.     

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.