固相萃取-气相色谱-质谱法同时测定化妆品中多环芳烃和邻苯二甲酸酯类物质

建立了固相萃取(SPE)-GC-MS法同时测定化妆品中的16种多环芳烃(PAHs)和17种邻苯二甲酸酯类(PAEs)的分析方法。样品经乙腈超声萃取后,经PSA/Slica玻璃柱净化,以Agilent Select PAH色谱柱分离,气相色谱-质谱法选择离子(SIM)监测测定。16种PAHs和17种PAEs在0.5~200μg/L范围内线性良好,相关系数均大于0.99;PAHs方法检出限为0.6~1.0μg/kg,方法定量限为1.9~3.3μg/kg,阴性样品3个添加水平的平均回收率为86.4%~112.2%;PAEs方法检出限为0.4~2.3μg/kg,方法定量限为1.5~7.6μg/kg,阴性样品3个添加水平的平均回收率为82.2%~114.1%;相对标准偏差均小于10%(n=6)。     

固相萃取-液相色谱-串联质谱法测定祛痘化妆品中硝基咪唑类药物

采用固相萃取(SPE)净化技术和高效液相色谱-串联质谱仪(HPLC-MS/MS),研究并建立了同时测定祛痘化妆品中6种硝基咪唑类药物(甲硝唑、替硝唑、奥硝唑、地美硝唑、洛硝唑和塞克硝唑)的方法。样品用酸化乙腈溶液提取,阳离子固相萃取小柱净化,以体积分数为0.1%甲酸乙腈溶液-体积分数为0.1%甲酸水溶液为流动相,经C18色谱柱梯度洗脱分离,采用HPLC-MS/MS多反应监测模式(MRM)定量检测。结果表明,6种硝基咪唑类药物在质量浓度1.0~50.0μg·L-1内线性关系良好,相关系数均大于0.999;方法定量限均为0.5 mg·kg-1;在祛痘水和祛痘膏样品中进行3个水平的添加实验,平均回收率为89.7%~108.0%,相对标准偏差(n=6)为2.3%~6.5%。     

高效液相色谱-串联质谱法测定化妆品中林可霉素和克林霉素

建立了一种简单、快速测定化妆品中林可霉素和克林霉素的高效液相色谱-串联质谱分析方法。样品经质量分数50%乙腈提取,正己烷液液萃取净化,高效液相色谱分离,电喷雾离子源正模式及多反应监测模式检测,外标法定量。林可霉素和克林霉素在15.0～300.0μg/L范围内线性关系良好,相关系数均大于0.9980,方法的检出限和定量限分别为0.10 mg/kg和0.30 mg/kg,加标回收率为86.1%～98.6%,精密度(n=6)为2.1%～8.1%。该方法具有净化效果好、定量准确、灵敏快速的特点,适用于化妆品中林可霉素和克林霉素化合物的检测确证。     

超高效液相色谱-串联质谱法检测鸡肉中大环内酯类药物残留量

建立鸡肉中3种大环内酯类药物的高效液相色谱-串联四级杆质谱(UPLC-MS/MS)残留分析方法。样本在乙腈水溶液提取下经PRIME HLB固相萃取柱净化,氮吹浓缩后定容过膜上机检测。在1.00~50.0μg/L线性范围内,竹桃霉素、克林霉素、交沙霉素的标准曲线相关系数分别为r=0.99994、r=0.99982、r=0.99962,方法检出限分别为0.59μg/kg、0.72μg/kg、0.48μg/kg。加标回收试验中竹桃霉素、克林霉素、交沙霉素加标浓度分别为3.00μg/kg、6.00μg/kg、30.0μg/kg,回收率范围分别为83.7%~102.8%,87.0%~110.0%,76.2%~103.0%。本方法适用于可食动物肌肉竹桃霉素、克林霉素、交沙霉素残留的检测。     

QuEChERS-超高效液相色谱-串联质谱法测定茶叶中丁醚脲的残留量

建立基于QuEChERS-超高效液相色谱-串联质谱测定茶叶中的丁醚脲的残留量的方法。样品经乙腈提取后用固相分散萃取剂净化除去杂质,以5mmol/L乙酸铵8∶2水:甲醇溶液,流动相B:5mmol/L乙酸铵甲醇溶液为流动相进行梯度洗脱,超高效液相色谱-串联质谱法正离子多反应监测模式(MRM)测定。丁醚脲在10μg/kg到200μg/kg的范围内线性良好,相关系数(R2)0.999。定量限10μg/kg为以茶叶为基质,在10、50、200μg/kg三个水平的加标回收率范围在70.4%~110.1%之间,相对标准偏差为5.0%~7.8%。该方法前处理快速简单,可用于对茶叶中丁醚脲的检测。     

固相萃取与液相色谱质谱联用技术测定化妆品中7种局部麻醉药

建立了固相萃取与液相色谱质谱联用技术同时测定化妆品中7种局部麻醉药普鲁卡因、氯普鲁卡因、普鲁卡因胺、辛可卡因、利多卡因、丁卡因、苯佐卡因的方法。样品经体积分数为1%三氯乙酸-乙腈提取,固相萃取净化,液相色谱分离,选择特征离子多反应监测(MRM)扫描模式测定,采用标准曲线法定量。结果表明,7种局部麻醉药在0.43~137μg/L范围内均呈良好的线性关系,相关系数均大于0.99,检出限为0.86~1.38μg/kg,加标回收率为80.1%~103.1%,相对标准偏差RSD小于5%(n=5)。     

QuEChERS/超高效液相色谱-串联质谱技术同时测定食品中13种植物生长调节剂残留

采用QuEChERS/超高效液相色谱-串联质谱技术同时测定食品中13种植物生长调节剂残留。样品经乙腈提取,分散固相萃取净化,以乙腈和2 mmol/L甲酸铵溶液为流动相进行梯度洗脱,Waters C18色谱柱分离,采用电喷雾多反应监测模式,外标法定量。13种植物生长调节剂线性良好,线性相关系数均>0.99,该方法的检出限在0.1~1.5μg/kg之间,定量限在0.3~5.0μg/kg之间。添加10、20和50μg/kg 3个浓度水平,13种植物生长调节剂的平均回收率在75.9%~110.3%之间,相对标准偏差在0.1%~11.9%之间。将该技术应用于实际样品的测试,结果表明,方法简便、快速、灵敏度高,适用于食品中13种植物生长调节剂残留的同时测定。     

超高效液相色谱-串联质谱法测定水产品中8种磺胺类药物残留量

建立了采用Oasis PRiME HLB固相萃取柱净化、超高效液相色谱-串联质谱法同时测定水产品中8种磺胺类药物残留量的检测方法。该方法的流程为样品经甲酸化乙腈提取,通过Oasis PRiME HLB固相萃取柱净化,高效液相色谱-串联质谱法测定,内标法定量。该方法在0.01~0.20μg/mL范围内线性良好,8种磺胺类药物相关系数均大于0.997。测定时添加浓度分别为2μg/kg和10μg/kg的加标样品,回收率均在70%~120%,方法准确性良好。     

UPLC-MS/MS法同时检测饲料中5种氨基糖苷类抗生素

建立了UPLC-MS/MS检测饲料中5种氨基糖苷类抗生素(链霉素、丁胺卡那霉素、安普霉素、庆大霉素、新霉素)的分析方法,样品用高氯酸溶液酸解及沉淀蛋白质,经MCX固相萃取净化、富集后,以10 mmol/L乙酸胺溶液(含0.1%甲酸)-乙腈作为流动相进行梯度洗脱,采用多反应监测(MRM)模式进行定性和定量分析。5种氨基糖苷类在10~500 ug/L的范围内线性关系良好(r≥0.9989)在10、50、100μg/kg添加水平下的回收率为74%~93%,RSD(n=6)为3.1%~8.1%,定量限(LOQ)为≤5μg/kg,该方法精密度好,灵敏度高,能简便、快速、准确地测定饲料中的5种氨基糖苷类抗生素。     

高效液相色谱-串联质谱法测定猪肝中5种α2受体激动剂

高效液相色谱-串联质谱测定猪肝中5种α2受体激动剂残留量。样品加入碳酸钠缓冲液,乙酸乙酯提取,MCX固相萃取净化后用甲酸-乙腈溶解,高效液相色谱-串联质谱测定。结果显示,5种α2受体激动剂在0～20μg/L浓度范围内线性良好,相关系数(r)均大于0.995;在0.5～4.5μg/kg添加水平下,5种α2受体激动剂回收率为70%～120%,相对标准偏差(RSD)均小于10%;本方法对猪肝中5种α2受体激动剂的检出限为0.5μg/kg。     

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.