高效液相色谱法测定香精中甲醛的含量

使用高效液相色谱测定了香精中甲醛的含量。香精中的甲醛经2,4-二硝基苯肼衍生化形成2,4-二硝基苯腙后,以乙腈提取,然后采用高效液相色谱测定。色谱柱:WatersNova-pakC18(4μm,3.9mm×150mm);柱温:30℃;流动相∶乙腈-水(体积比为45∶55);检测波长352.0nm;运行时间:9min;流速:1mL/min。甲醛在0.01～10μg/mL范围内呈良好的线性关系,相关系数为0.9998,回收率在96.6%～107.9%范围内,相对标准偏差为2.7%,检测限为26.4ng/g。该方法可满足香精中甲醛的检验工作。     

HPLC测定香砂六君丸中木香烃内酯的含量

目的:测定不同批次香砂六君丸中的木香烃内酯的含量。方法:采用HPLC法,色谱柱为Kromasil C18(250 mm×4.6 mm,5μm);流动相:甲醇-水(65∶35);检测波长为225 nm;流速为1.0 mL/min;柱温:30℃,进样体积10μL。结果:木香烃内酯1.05～21.00μg/mL与峰面积呈良好的线性关系(r=0.9999),平均加样回收率为101.08%,RSD=1.3%(n=6);5批次香砂六君丸中的木香烃内酯的含量为0.12%。     

基于HPLC法的止咳宝片中橙皮苷的含量测定

目的:建立止咳宝片中橙皮苷含量测定的方法。方法:采用反相高效液相色谱法,色谱柱为Diamonsil-C18柱(150mm×4.6mm,2.7μm);乙腈-水(21∶79)为流动相;流速1.0mL·min~(-1);检测波长283nm,柱温35℃。结果:橙皮苷浓度在5.44～54.40μg·mL~(-1)之间具有良好的线性关系(r=0.9990),平均加样回收率为102.6%,方法精密度(RSD)为0.26%(n=6)。结论:该法操作简便,重复性好,结果准确,可用于止咳宝片的含量测定。     

HPLC法测定小儿咳喘灵中麻黄碱、伪麻黄碱的含量

建立小儿咳喘灵颗粒中盐酸麻黄碱和盐酸伪麻黄碱的含量测定方法。采用synergi polar色谱柱(菲罗门,250 mm×4.6 mm,5μm);流动相:甲醇-0.092%磷酸溶液(含0.04%三乙胺和0.02%二乙胺(0.1∶99.9);检测波长:210 nm。盐酸麻黄碱在9.8×10~(-3)~98×10~(-3)μg,盐酸伪麻黄碱在9.4×10~(-3)~94×10~(-3)μg范围内与峰面积值呈良好的线性关系,平均加样回收率分别为99.16%和97.85%(n=9),RSD分别为1.40%和1.47%(n=9)。本法准确可靠,可用于小儿咳喘灵颗粒的质量控制。     

反相高效液相色谱法测定N-（3-叔丁基-1H-吡唑-5-基）-N’-羟基-4-硝基苯甲脒含量

目的:采用反相高效液相色谱法建立质量控制的方法.方法:色谱柱为Inerstil ODS-3(250×4.6 mm,5 μm),流动相为乙腈-水-乙酸-三乙胺(50∶50∶0.2∶0.2),流速为1 mL*min-1,柱温为室温,检测波长为254 nm.结果:空白、中间体及杂质对样品测定不产生干扰;102E的浓度在0.2156～1.394 mg*mL-1范围内与峰面积呈良好线性关系(r=0.999 8,n=5);重复性良好(RSD=0.52%,n=6);检测限为32.5 μg*mL-1;平均回收率为99.61%(n=9).结论:该方法可以用于102E的含量测定.     

反相高效液相色谱法同时测定生物转化液中苯乙酮和肉桂酸

建立RP-HPLC法测定生物转化液中苯乙酮和肉桂酸的含量。色谱条件:采用Kromasil-100AC18柱(250 mm×4.6 mm,5μm);以甲醇-水-冰醋酸(体积比为75∶25∶0.05)为流动相;流速为1.0 mL/min;检测波长为246 nm;柱温为室温。结果表明,苯乙酮在1.60~320.0μg/mL范围内呈良好线性关系(r=0.999 2);肉桂酸在2.00~400.0μg/mL范围内呈良好线性关系(r=0.999 6)。苯乙酮和肉桂酸的平均回收率分别为100.42%和101.75%,相对标准偏差(RSD)分别为1.3%和1.7%。     

HPLC测定吡喏克辛钠滴眼液中尼泊金酯的含量

目的:测定吡喏克辛钠滴眼液中尼泊金酯的含量。方法:高效液相色谱法,色谱柱:Alltech C18柱(4.6 mm×250 mm,5μm);流动相:乙腈∶水(70∶30);检测波长:254 nm。结果:用高效液相色谱法测定,尼泊金甲酯和丙酯的平均加样回收率分别为99.59%和99.68%,在样品中的平均含量分别为1.187×10-3 mol/L和4.216×10-4 mol/L。结论:建立了同时测定吡喏克辛钠滴眼液中对羟基苯甲酸甲酯、丙酯的高效液相色谱分析法,该方法操作简单,结果较好,能够广泛用于食品、药品、洗发液等的尼泊金酯含量的测定。     

金银花露中苯甲酸钠的含量测定方法学研究

建立高效液相色谱分析金银花露中苯甲酸钠的含量测定方法。采用Inertsil ODS-3色谱柱(5μm,4.6mm×250mm);以0.02mol·L~(-1)醋酸铵溶液-甲醇(90∶10)为流动相;流速1.0mL·min~(-1);检测波长为230nm;柱温:室温。苯甲酸钠在24.4~122.0μg·mL~(-1)范围内线性关系良好,苯甲酸钠的平均回收率为102.20%,RSD为0.49%。该方法操作简便,测定结果准确可靠,可有效的用于金银花露中苯甲酸钠含量测定。     

HPLC测定逍遥颗粒中的芍药苷

目的:测定不同批次逍遥颗粒中的芍药苷的含量。方法:采用HPLC法,色谱柱为Agilent TC C18(250 mm×4.6 mm,5μm);流动相为乙腈-1%磷酸溶液(20∶80);检测波长为230 nm;柱温为30℃;流速为1.0 ml/min;进样体积10μL。结果:芍药苷1.35~27.00μg·mL-1与峰面积呈良好的线性关系(r=0.999),平均加样回收率为98.55%,RSD=1.8%(n=6);5批次逍遥颗粒中的芍药苷的含量为0.32%。结论:所用方法简单、稳定,芍药苷的含量可作为逍遥颗粒的品质评价依据之一。     

HPLC法测定天山花楸叶提取物黄酮苷的含量

为了建立天山花楸叶中总黄酮苷含量的测定方法,对样品酸水解处理再进行HPLC分析,色谱柱为Waters-C18(150 mm×4.6 mm,5μm),柱温25℃,使用可变波长检测器;流动相为甲醇-乙腈-0.4%磷酸水溶液,梯度洗脱程序为0 min(12∶20∶68)-10 min(52∶0∶48)-18 min(72∶0∶28);流速1.0 mL/min,检测波长为360 nm。结果表明:槲皮素浓度在5.98～47.84μg/mL之间与色谱峰面积呈良好的线性关系,回归方程A=66.96C-5.9964,r=0.9995。平均回收率94.86%,RSD=1.9%;山柰素浓度在4.04～28.28μg/mL之间与色谱峰面积呈良好的线性关系,回归方程A=50.114C-19.529,r=0.9999,平均回收率93.89%,RSD=2.7%;其黄酮苷百分含量为(12.62±0.40)%。该方法干扰少,灵敏,简便,重现性好,可为天山花楸叶的药用开发利用提供质量控制方法。     

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.     

Methyl 2,4,6-decatrienoates Attract Stink Bugs and Tachinid Parasitoids

Halyomorpha halys (Stål) (Pentatomidae), called the brown marmorated stink bug (BMSB), is a newly invasive species in the eastern USA that is rapidly spreading from the original point of establishment in Allentown, PA. In its native range, the BMSB is reportedly attracted to methyl (E,E,Z)-2,4,6-decatrienoate, the male-produced pheromone of another pentatomid common in eastern Asia, Plautia stali Scott. In North America, Thyanta spp. are the only pentatomids known to produce methyl 2,4,6-decatrienoate [the (E,Z,Z)-isomer] as part of their pheromones. Methyl 2,4,6-decatrienoates were field-tested in Maryland to monitor the spread of the BMSB and to explore the possibility that Thyanta spp. are an alternate host for parasitic tachinid flies that use stink bug pheromones as host-finding kairomones. Here we report the first captures of adult and nymph BMSBs in traps baited with methyl (E,E,Z)-2,4,6-decatrienoate in central Maryland and present data verifying that the tachinid, Euclytia flava (Townsend), exploits methyl (E,Z,Z)-2,4,6-decatrienoate as a kairomone. We also report the unexpected finding that various isomers of methyl 2,4,6-decatrienoate attract Acrosternum hilare (Say), although this bug apparently does not produce methyl decatrienoates. Other stink bugs and tachinids native to North America were also attracted to methyl 2,4,6-decatrienoates. These data indicate there are Heteroptera in North America in addition to Thyanta spp. that probably use methyl 2,4,6-decatrienoates as pheromones. The evidence that some pentatomids exploit the pheromones of other true bugs as kairomones to find food or to congregate as a passive defense against tachinid parasitism is discussed.