反相高效液相色谱法测定1-(4-硝基苯)-3-(5-氯-2-吡啶)三氮烯

采用Zorbax Eclipse XDB-C8(4.6mm内径×150mm,5μm)色谱柱,乙腈流动相,流速0.70mL/min,检测波长407nm,建立了测定标题化合物的反相高效液相色谱法。该方法的线性范围是0.5~12.0μg/mL,回归方程为A=82.06c+10.16(r=0.9996),相对标准偏差3.218%(c=6.0μg/mL,n=5),检出限为0.05427μg/mL,平均回收率在96.81%~105.1%之间。     

示差脉冲极谱法测定柠檬黄

建立了示差脉冲极谱法测定饮料中的合成色素柠檬黄的新方法。在pH 6.00的磷酸盐缓冲溶液中,柠檬黄在-0.59 V处产生一灵敏的还原峰,在1.25×10-6～4.37×10-5 mol/L浓度范围内,其峰电流与浓度呈线性关系,线性回归方程为ip（μA）=2.46×106 c（mol/L）＋11.4（相关系数r=0.970）,实验检出限为0.27μg/mL。利用该方法测定了两种市售饮料中柠檬黄,加标回收率在87.5%～109.6%之间。     

结晶紫褪色光度法测定四溴双酚A的含量

在硫酸介质中,四溴双酚A对Fenton反应产生的羟基自由基氧化结晶紫的反应具有抑制作用,据此建立了分光光度法测定四溴双酚A含量的新方法。探讨不同酸介质、硫酸用量、结晶紫浓度、H2O2浓度、反应时间和反应温度等因素对反应体系的影响。在选定实验条件下,方法的线性回归方程为:ΔA=0.0027+22732c,相关系数r2=0.9931,线性范围:0.004⁰.032μg/mL,检出限为3.7×10-7μg/mL。将方法应用于实际样品的测定,加标实验回收率为86%0.032μg/mL,检出限为3.7×10-7μg/mL。将方法应用于实际样品的测定,加标实验回收率为86%¹08%,相对标准偏差(RSD)为4.3%108%,相对标准偏差(RSD)为4.3%⁵.1%。该方法简便快速,结果令人满意。     

分光光度法快速检测饮料中日落黄的研究

采用分光光度法测定饮料中的日落黄,确定了日落黄的最大吸收波长,结果表明:日落黄的最大吸收波长为482 nm,线性回归方程为:y=33.055x+0.0024,线性相关系数r=0.9998,测定饮料中日落黄含量为0.06418 mg/mL,精密度好,相对标准偏差(RSD)为0.15%,在饮料中的加标回收率在96.83%～...     

三波长分光光度法同时测定食品添加剂

本文采用三波长分光光度法同时测定食品中日落黄和柠檬黄。选择 30 5、347、4 6 4nm为测定日落黄的波长组合 ,其回归方程为ΔΑ =0 0 0 30 93+0 0 135 7C ,r日 =0 9999,线性范围为 3～ 95 μg·mL-1;选择 345、4 4 4、5 0 8nm为测定柠檬黄的波长组合 ,其回归方程为ΔΑ =0 0 0 1392 +0 0 2 5 6 1C ,r柠 =0 9999,线性范围为 4～ 85 μg·mL-1。实验表明 ,本方法很好的消除了日落黄与柠檬黄之间的干扰 ,回收率达到 95 5 6 %～10 2 1% ,RSD日 =0 6 2 31% ,RSD柠 =0 70 89% ,结果令人满意     

十六烷基三甲基溴化铵增敏二甲酚橙光度法测定化妆品中铅

在六次甲基四胺缓冲溶液体系中(pH=5 5),铅(Ⅱ)-二甲酚橙(XO)-表面活性剂十六烷基三甲基溴化铵(CTAB)形成红色的三元离子缔合物,其最大吸收波长为594nm,比不加表面活性剂红移了54nm。摩尔吸光系数为1 86×105L·mol-1·cm-1。含铅量在0～2μg/mL内符合比耳定律,线性回归方程为A=0 088+0 0132c(μg/mL),相关系数为0 9891。用于化妆品中微量铅离子的测定,回收率为96 0%～102 0%     

荧光分析法测定土壤中的微量铅

基于在浓盐酸介质中Pb2+所形成PbCl42-在紫外光的照射下发射蓝色荧光的原理,建立荧光法测土壤中微量Pb含量的方法。该方法的线性范围为0.03~2.00μg/mL,检出限为9.1×10-3μg/mL,用于土壤样品中微量Pb的测定,加标回收率96.1%~103.3%,结果满意。     

2-苯基-4-对氯苯基-1,5-苯并硫氮杂-α-(丁二酰亚胺基)-β-内酰胺的高效液相色谱法分析

采用Hypersil-ODS2(4.6mm×250mm,5μm)色谱柱,乙腈-水(70∶30)流动相,242nm检测波长,建立了测定2-苯基-4-对氯苯基-1,5-苯并硫氮杂-α-(丁二酰亚胺基)-β-内酰胺的高效液相色谱法。该法线性范为0～0.1mg/mL,回归方程为A=1.63×108c-2.86×105,相关系数r=0.9994,相对标准偏差为0.33%(c=0.06mg/mL,n=5),检出限为0.08μg/mL。平均回收率在97.2%～102.4%之间。该法重现性好,灵敏度高,简单,快速,准确。     

双波长分光光度法测定饮料中亮蓝和胭脂红

建立了双波长紫外-可见分光光度法联合测定2种食用色素亮蓝和胭脂红的新方法。亮蓝和胭脂红有很好的光吸收特性,最大吸收波长分别为629.0nm和509.0nm,并且双组分在各自的最大吸收波长处的吸收互不干扰,因而可实现双组份的同时测定。在2.00×10-6～3.00×10-5 mol/L范围内,亮蓝的浓度与其吸光度呈良好的线性关系,线性回归方程A=1.07×105c+0.067(相关系数r=0.997),检出限为1.00×10-6 mol/L;在1.00×10-6～1.600×10-5 mol/L范围内,胭脂红的浓度与其吸光度呈良好的线性关系,线性回归方程A=1.55×104c+0.023(相关系数r=0.999),检出限为1.00×10-5 mol/L。利用本方法测定了2种市售饮料中亮蓝和胭脂红的含量,加标回收率分别为97.0%和97.5%。     

阻抑动力学光度法测定水样中的痕量铝

基于在CTAC介质中，铝(Ⅲ)对十六烷基三甲基氯化铵(CTAC)催化结晶紫的褪色反应有明显的抑制作用，建立了一种抑制-催化褪色光度法测定痕量铝(Ⅲ)的新方法，研究了影响阻抑褪色反应的因素。结果表明，阻抑反应体系的最大吸收波长为584 nm,方法的线性范围为0.04～0.4μg/mL,线性回归方程为ΔA=0.722 7c+0.068 7(c的单位为μg/mL),相关系数r=0.963 8,检出限为0.063μg/mL,相对标准偏差(RSD)为1.355%。该方法用于环境和工业水样中痕量铝的测定，相对标准偏差为3.7%～4.6%,回收率为96.8%～104.6%。     

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。