离子色谱法同时分离测定察尔汗盐湖老卤中阴离子

建立了同时分离测定察尔汗盐湖老卤中氯离子、溴离子、碳酸根、硫酸根、碘离子的离子色谱-电导检测分析方法。利用AS19型分离柱和AG19型保护柱,采用电导检测实现了老卤中5种阴离子的同时分离测定。探索了淋洗液浓度及流速和柱温等因素对5种阴离子同时分离测定的影响并确定了最优离子色谱分离测定条件。在22 mmol/L氢氧化钾溶液等度淋洗、淋洗液流速为1.0 m L/min、柱温为32℃条件下,5种离子在23 min内实现完全分离。各离子检出限分别为:氯离子,0.282 0μg/L;溴离子,0.942 8μg/L;碳酸根,5.800 7μg/L;硫酸根,0.812 4μg/L;碘离子,4.272 0μg/L。各离子相关系数不低于0.999 80,连续10次进样测得峰高、峰面积和保留时间的相对标准偏差均在1.43%以下,平均加标回收率在90.06%~109.80%之间。该方法重复性好,精确度及灵敏度高,可用于察尔汗盐湖老卤中氯离子、溴离子、碳酸根、硫酸根、碘离子的同时分离测定。     

离子色谱法测定水中的六种阴离子

建立了水中F~-、Cl~-、Br~-、NO_2~-、NO_3~-和SO_4~(2-)六种阴离子的离子色谱测定方法。方法采用ICS-900型离子色谱仪,IonPac AS19(4 mm×250 mm)色谱柱,淋洗液自动发生装置在线产生高纯度KOH作淋洗液,考察了淋洗液浓度和流速对六种离子分离效果的影响,结果表明在KOH淋洗液浓度15 mmol/L,流速1.0mL/min,电流量50mA,进样量250μL的色谱条件下,六种共存阴离子分离效果良好,运行时间为15min。方法的线性范围广、线性相关性好(R~2=0.9947~0.9997)精密度高,相对标准差(RSD)为0.38%~1.56%,平均加标回收率为84.0%~108.0%,最低检测限为0.0100~0.0298mg/L。该法测定矿泉水、自来水和地表水等中的六种阴离子,具有操作简便、灵敏度高、准确、快速等优点。     

离子色谱法测定化工生产废水中的溴离子和氯酸根离子

采用离子色谱法对化工生产废水中的溴离子和氯酸根离子进行了有效的分离和测定.通过实验确定最佳色谱条件:淋洗液浓度为3.6 mmol/L Na2CO3,流速为0.8 mL/min,色谱柱为Metrosep A Sup 7-250/4.0,柱温45℃.利用该检测方法测定溴离子加标回收率为85％～105％,氯酸根离子加标回收率...     

柱切换离子色谱法测海水中的草酸根离子

建立了柱切换离子色谱法测海水中草酸根离子的方法。采用Dionex Ion Pac AS11-HC(4 mm×250 mm)阴离子分离柱和AG11-HC(4 mm×50 mm)保护柱分离海水中草酸根,采用20 mmol/L KOH淋洗液,流速为1.0 m L/min等度淋洗,通过柱切换除去海水中大部分的高浓度阴离子(Cl~-、SO_4~(2-)和Br~-),分离出的C_2O_4~(2-)收集于富集柱,然后经过阀切换,将目标离子从富集柱上洗脱,进入阴离子分析柱分离,此时淋洗液换成30 mmol/L Na OH溶液,流速为0.8 m L/min等度淋洗,电导法检测。结果表明,在线性范围为0.5~10.0 mg/L内其相关系数为0.999 4,相对标准偏差为1.48%(n=6),最低检出限为4.35μg/L(S/N=3),所得样品回收率为85.3%~110.0%。该实验方法简单方便,且具有较好的重现性和较低的检出限,可用于检测海水中的草酸根离子。     

离子色谱法同时分析水中2,4-滴、草甘膦和灭草松

采用离子色谱法对饮用水中2,4-滴、草甘膦和灭草松进行同时检测。以AS23柱分离,在20mmol/LNaOH为淋洗液、流速为1mL/min、进样量1mL、电导检测的条件下,方法检测限分别为:5.5μg/L、5.1μg/L和30.6μg/L,加标回收率为:100.4%～105.7%,相对标准偏差为1.56%～2.23%(n=7)。     

离子色谱法同时测定废水中多种低分子有机酸

建立了离子色谱电导同时检测废水中乳酸、冰乙酸、丙酸、甲酸、异丁酸、丁酸、异戊酸和戊酸的方法。经活化的C18柱,采用Ion Pac AS11-HC色谱柱,淋洗液为1 mmol/L的KOH溶液,流速1.0 m L/min,抑制电流3 m A。方法检出限(S/N=5)在0.025~0.030 mg/L之间,方法在0.098~11.953 mg/L添加水平,加标回收率在80%~120%之间,测定值的相对标准偏差(n=6)在0.61%~2.00%之间。该方法简便、灵敏、准确,适用于废水中低分子有机酸含量的快速分析。     

辛伐他汀片中有关物质的HPLC测定

建立了HPLC法测定辛伐他汀片中有关物质.采用VP-ODS(250mm×4.6mm,5μm)色谱柱,乙腈-0.025mol/L磷酸二氢钠溶液(pH4.5)(65:35)为流动相,检测波长238nm,柱温35℃,流速1mL/min.在0.1-3.0μg/mL范围内线性关系良好(r=0.9999),该方法分离度好,塔板数高,最低检测量可达0.2μg.     

负载Ag~+ D72树脂色谱柱分离纯化花生四烯酸工艺的建立

目的建立负载Ag+D72树脂色谱柱分离纯化花生四烯酸(Arachidonic acid,AA或ARA)的工艺。方法采用负载Ag+D72树脂色谱柱对微生物油脂中的ARA进行分离纯化,确定最佳分离纯化参数,利用气相色谱法检测ARA的含量。结果负载Ag+D72树脂的最大饱和吸附量约为9 mg/g干树脂,在吸附温度0℃、不饱和脂肪酸甲酯上样质量浓度5 mg/ml,5%丙酮正己烷溶液(体积比)洗脱、解吸温度30℃、洗脱流速2 ml/min的条件下,ARA的纯度达89.4%,收率达79.3%。结论负载Ag+D72树脂色谱柱可有效分离纯化微生物油脂中的ARA,为进一步生产高纯度的ARA,进而规模化生产ARA产品提供了参考。     

水中常见阴离子和有机酸的离子色谱分析方法研究

建立了同时测定水样中常见阴离子和有机酸的电导抑制-离子色谱分析方法。以阴离子交换色谱柱(IonPac AS11)(250mm×4.0mm)和IonPac AG11(50mm×4.0mm)为分离柱和保护柱,进样25μL,以7.5mmol/L NaOH为淋洗液,0.7mL/min的流速淋洗,抑制电导检测。分析测定了水样中氯乙酸、Cl-、NO-2、NO-3、琥珀酸、酒石酸、SO2-4、草酸的含量。结果表明:该方法在20min内能完成分析检测;加标回收率值为72.25%~109.69%,相对标准偏差(RSD)值5%。通过该方法分析检测了昆明市呈贡新区河流水和湖泊水,结果较为满意。     

IC法测定乙烯利水剂中乙烯利、亚磷酸、磷酸的含量

建立了IC法检测乙烯利水剂中乙烯利、磷酸、亚磷酸的方法。选用SH–AC–1阴离子分离柱,淋洗液选用3.6 mmol/L Na2CO3+4.5 mmol/L NaHCO3,等度淋洗,流速2.0 mL/min,进样量10μL,抑制电导检测,样品水溶解。在此条件下,线性相关系数均大于0.999;亚磷酸、磷酸和乙烯利检出限(S/N=3)分别为12.1?g/L、53.4μg/L和73.7μg/L;相对标准偏差(RSD)为0.58%、2.87%和1.26%,样品平均加标回收率在97.0%～100.1%,重现性好。该方法简便、快速、灵敏、准确,可以用于乙烯利水剂中乙烯利、磷酸和亚磷酸的同时测定。     

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.     

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.