HPLC法同时测定发酵液中纽莫康定Ao与Bo的含量

采用HPLC方法同时测定发酵液中纽莫康定A0与B0的含量.色谱柱为SepaxSapphire C18 (4.6 mm×250mm,5 μm),流动相为甲醇-水(体积比45:55,内含0.1‰三氟乙酸),流速为1.0 mL·min-1,紫外检测波长为214nm.结果表明,纽莫康定A0与B0的浓度分别在47.5～191.4...     

高效液相色谱法测定某能量饮料中七种水溶性维生素的研究

报道了利用反相液相色谱法测定某能量饮料中七种水溶性维生素(维生素C、PP、B5、B6、B1、B2、叶酸).样品利用Supelco C18(500mg)固相萃取柱萃取后,直接注入高效液相色谱柱Phenominex C-18(250 mm×4.6 mm),采用等度洗脱,流动相为0.1 mol/LKH2PO4(pH=7.0)-甲醇(体积比90∶10),流速为0.5 mL/min.各个化合物的保留时间以及UV谱图与标准谱图的对比可以指认各化合物.该方法的检测限为0.05～0.2 mg/L,平均回收率为94.71%～97.03%.     

高效液相色谱法测定覆盘子没食子酸的含量

研究采用反相高效液相色谱法测定覆盆子中没食子酸的含量.色谱条件:色谱柱C18柱(DiamonsilTM 20 mm×5 mm,5μm),流动相采用甲醇:0.5%的磷酸溶液(10∶90),检测波长为273 nm,柱温25℃,进样量20 μl,流速0.8 ml/min,经方法学考察,线性关系良好,r=0.9990,回收率达99.4%.     

SPE-HPLC测定制药废水中土霉素残留量

采用固相萃取法提取水样,用高效液相色谱(HPLC)测定废水中土霉素(OTC).固相萃取小柱为Octadecyl 18/18%(500 mg/6 mL),洗脱液为甲醇,色谱柱为Eclipice plus C18柱(3.5 μm,4.6mm×100mm),流动相为乙腈:0.01 mol/L柠檬酸溶液=25:75(v/v pH=2.5),流速0.4 mL/min,检测波长为355nm.标准曲线线性良好,其回归方程及相关系数r分别为y=64.117 77+27.398 479 9x,r=0.999 94,精密度(RSD)为0.9%～2.8%,回收率在87%～115%之间.该方法方法简便,结果可靠,灵敏度高,适用于废水中土霉素残留量检测.     

HPLC法测定化妆品中的黄芩甙

建立了利用高效液相色谱检测化妆品中黄芩甙的方法。样品使用75%乙醇超声提取20min,8000r/min下离心10min,ZORBAXSB C18柱分析（250mm×4.6mm,5μm）,流动相乙腈∶0.1%磷酸=22∶78,检测波长为276nm。该方法线性范围1.00～100.0μg·mL^-1,加标回收率85.1%～104.6%,检出限5.0mg·kg^-1。方法简便、准确、重现性好,适用于化妆品中有效成分黄芩甙检测。     

反相高效液相色谱法测定化妆品中的几种防晒剂

采用反相高效液相色谱法测定化妆品中的10种防晒剂,用色谱柱为Waters Symmetry shield C18柱(250mm ×4.6 mm i.d,5 μm),V(甲醇):V(水)=85:15为流动相,检测波长310 nm,回收率为98.1%～101.0%,相对标准偏差小于5%.     

高效液相色谱法测定3,4,5-三甲氧基苯甲酸工业品中没食子酸的含量

建立了一种利用高效液相色谱测定3,4,5-三甲氧基苯甲酸工业品中没食子酸含量的分析方法。在C18色谱柱(4.6×150 mm,5μm)上通过考察流动相种类、梯度起止比例及洗脱时间对保留的影响来优化色谱条件。最终以甲醇和0.1%高氯酸水溶液(v/v)为流动相,梯度洗脱程序:0~3 min,20%甲醇;3~8 min,20%~65%甲醇;8~16 min,65%甲醇;紫外检测波长:270 nm。实验结果表明,在优化的色谱条件下没食子酸在1.7×10-4~0.1 mg·m L-1范围内线性关系良好(r2=0.9999),日内和日间测定相对标准偏差分别为1.1%和1.3%,回收率在102.3%~105.7%之间。此快速准确方法可用于3,4,5-三甲氧基苯甲酸工业品的质量控制。     

HPLC法测定糯米藤中槲皮素和山柰酚的含量

建立测定糯米藤中槲皮素和山柰酚含量的方法.采用HPLC法测定糯米藤中槲皮素和山柰酚的含量.色谱柱为X-Peonyx C18柱(250 mm×4.6 mm,5μm),流动相为甲醇-0.1％磷酸(55:45),检测波长为360 nm,流速1.0 mL·min-1,柱温30℃,进样量为10μL.槲皮素和山柰酚的进样量分别在0...     

HPLC-ELSD法测定新霉素氟轻松乳膏中新霉素的含量

建立新霉素氟轻松乳膏中新霉素的含量测定方法.采纳HPLC-ELSD法,色谱柱型号为Agilent ZORBAX SB-C18(250 mm×4.6 mm,5μm);流动相A为乙腈,流动相B为0.1 mol·L-1三氟乙酸水溶液,梯度洗脱;流动相速度为0.8 mL·min-1,加热管温度为105℃,柱温为25℃.新霉素在...     

高效液相色谱测定40%乙烯利中6-苄氨基嘌呤方法的研究

首次建立了高效液相色谱测定40%乙烯利中6-苄氨基嘌呤含量的方法.色谱柱为Symmetry C18(150 mm×3.9 mm×5 μm);流动相为甲醇-水(V/V=50:50);流速为0.8 mL/min;线性回归方程为y=9.35×106x-3.52×103,r=0.999 8,线性范围为32.9～411 μg;加标回收率平均值为98.2%,RSD为1.42%.     

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.     

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.     

2007～2008年世界塑料工业进展

收集了2007年7月～2008年6月世界塑料工业的相关资料,介绍了2007～2008年国外塑料工业的发展情况,提供了世界塑料产量、消费量及全球各类树脂的需求量及产能情况.按通用热塑性树脂(聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂)、工程塑料(尼龙、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚)、特种工程塑料(聚苯·硫醚、液晶聚合物、聚醚醚酮)、通用热固性树脂(酚醛、聚氨酯、不饱和聚酯树脂、环氧树脂)不同品种的顺序,对树脂的产量、消费量、供需状况及合成工艺、产品应用开发、树脂品种的延伸及应用的进一步扩展等技术作了详细介绍.     

2005～2006年国外塑料工业进展

收集了2005年7月～2006年6月国外塑料工业的相关资料,介绍了2005—2006年国外塑料工业的发展情况。提供了世界塑料产量、消费量及全球各类树脂生产量以及各国塑料制品的进出口情况。作为对比,介绍了中国塑料的生产情况。按通用热塑性树脂（聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂）、工程塑料（聚酰胺、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚）、通用热固性树脂（酚醛、聚氨酯、不饱和树脂、环氧树脂）、特种工程塑料（聚苯硫醚、液晶聚合物、聚醚醚酮）的品种顺序,对树脂的产量、消费量、供需状况及合成工艺、产品开发、树脂品种的延伸及应用的扩展作了详细的介绍。