固定化酶荧光毛细分析法测定乳酸

基于乳酸脱氢酶(LDH)和烟酰胺腺嘌呤二核苷酸(NADH)氧化还原体系,提出了乳酸的液态酶荧光毛细分析方法(IE-FCA)。在激发波长350nm、发射波长460nm条件下,用LE-FCA法成功的对乳酸样品中的乳酸进行了测定;其线性范围为1.0-5.0mmol/L,r>0.9930,检出限为0.38mmol/L,RSD<1.3%。IE-FCA重现性好、操作简便、能节省贵重的酶试剂、样品用量仅为18μL,测定成本低;可实现乳酸的微量化、快速化测定。     

钬联吡啶配合物增强荧光法测定青霉素的研究

以2,2'-联吡啶为配体合成了稀土元素钬的配合物,并对其进行了荧光表征,测得最佳激发波长为314 nm;发射波长为443 nm。不同浓度的氨苄青霉素对该配合物特征峰下的荧光强度有良好的增强作用,研究了溶剂与pH条件等对配合物荧光强度的影响,提出一种测定青霉素含量的新方法。方法的线性范围为9.0×10~(-6)~8.0×10~(-5) mol/L,检出限8.0×10~(-6) mol/L,应用于实际样品测定,结果令人满意。     

分散液相微萃取荧光法测定果蔬中残留吡蚜酮

[目的]利用分散液相微萃取和表面活性剂增敏,建立果蔬中吡蚜酮残留量的荧光分光光度快速测定法。[方法]用二氯甲烷作为萃取剂,丙酮作为分散剂对样品进行前处理。以水作溶剂,320μL十二烷基硫酸钠(SDS)(0.1 mol/L)作增敏剂,室温静置10 min。1 cm石英比色皿作吸收池,于激发波长(λ_(ex))312 nm、发射波长(λ_(em))349 nm处测定荧光强度。[结果]在0.02~1.00 mg/L范围内,吡蚜酮浓度与荧光强度线性关系良好,检出限为0.0196 mg/kg。加标回收率为87.73%~99.06%,RSD为2.93%~9.67%。[结论]新建方法可用于水果蔬菜中吡蚜酮残留测定。     

离子交换色谱-荧光检测法快速测定浓缩果汁中噻菌灵残留量

建立离子交换色谱-荧光检测法快速测定6种浓缩果汁中噻菌灵残留量的分析方法。样品直接用水稀释,采用LC-SCX离子交换色谱柱(25cm×4.6mm,5μm)分离,荧光检测器检测,以0.1mol/L磷酸二氢钾溶液(pH3.0)-乙腈(体积比为70∶30)为流动相,流速1.0mL/min,荧光激发波长307nm,发射波长359nm。样品中噻菌灵能得到良好的分离,在0.001￣0.1mg/L范围内峰面积与质量浓度呈良好的线性关系(r为0.9999),回收率及重现性良好。方法简便、快速、灵敏、准确,可用于浓缩果汁中噻菌灵残留的检测。     

荧光光谱法测定食品中的苋菜红含量

建立了荧光光谱法测定食物中的苋菜红色素含量的方法,选择320 nm处为最佳激发波长,425 nm处为最佳发射波长,扫描苋菜红的荧光光谱图。苋菜红浓度在1.5~14 mg/L范围内与其荧光强度具有良好的线性关系,线性回归方程为F=46.38634+31.48683 C(mg/L),相关系数r=0.9991,检出限为0.031 mg/L。利用荧光光谱法测定食物中苋菜红的含量,测得样品的回收率为92.13%~105.61%。荧光法具有灵敏度高、选择性强、信息量丰富、方法简便、高效精确等诸多特点。     

混合胶束对苏丹红Ⅰ的荧光增强作用及其分析应用

研究了各种条件下苏丹红Ⅰ的荧光性质,发现在pH9.00的Tris-HCl缓冲溶液中,阴离子表面活性剂十二烷基苯磺酸钠(SDBS)和阳离子表面活性剂十六烷基三甲基溴化铵(CTAB)的混合胶束对苏丹红Ⅰ的荧光具有增强作用,荧光激发波长325nm,发射波长586nm,其荧光增强程度与苏丹红Ⅰ的浓度具有良好的线性关系,据此建立了微量苏丹红Ⅰ的荧光分析法,线性范围5.00×10-7～1.30×10-5mol/L(0.1～2.5μg/mL),检出限为9.30×10-11mol/L(23ng/mL)。该方法已成功用于合成样品的测定。     

三聚氰胺荧光熄灭法测定Ag(Ⅰ)的研究

基于Ag(Ⅰ)对三聚氰胺的荧光熄灭作用,建立了测定Ag(Ⅰ)的荧光分析方法.在pH为5.0的HAcNaAc缓冲体系中,测定的最大激发波长λex为256.0 nm,最大发射波长λem为363.0 nm,线性范围为2.0x10-6 ～2.4×10-2 mol/L,检出限为4.3×10-7 mol/L.将其用于废定影液中痕量Ag(Ⅰ)的测定,结果满意.     

新型基质固相分散萃取净化-高效液相色谱荧光检测法测定香精香料中的黄曲霉毒素B1、B2、G1和G2

建立了一种新型基质固相分散萃取净化技术结合高效液相色谱-荧光检测法(HPLC-FLR)测定香精香料中的4种黄曲霉毒素(B1、B2、G1、G2)的方法。该前处理装置结合基质分散萃取和柱层析对样品进行在线萃取、净化和衍生化,之后对样品浓缩并利用LC-FLR分析测定。色谱方法以水(体积分数65%)和乙腈(体积分数35%)为流动相,0.2 mL/min流速下梯度洗脱,采用C_(18)色谱柱进行液相色谱分离,荧光光度法测定(激发波长360 nm,发射波长440 nm)。结果表明,该方法的前处理集净化萃取浓缩和衍生化为一体,操作方便且稳定性强,溶剂可回收;4个目标物质在0.5~120μg/L范围内具有较好的线性,各待测物的线性相关系数均大于0.999,检出限为0.15~0.35μg/L;对实际样品进行不同浓度的添加,平均回收率为76%~93%,日内精密度和日间精密度均5%,结果较为理想。该方法能较好地应用于香精香料实际样品中4种黄曲霉毒素的测定。     

苯基荧光酮-SDBS-β-CD-荧光猝灭法测定微量Mn(Ⅱ)

在pH7.4乙酸-乙酸钠介质中,有锰(Ⅱ)存在时,反应体系苯基荧光酮(PF)、β-环糊精(β-CD)及十二烷基苯磺酸钠(SDBS)所产生的荧光,由于锰(Ⅱ)与PF反应生成了配合物而产生猝灭现象,而且荧光强度的减弱程度与锰(Ⅱ)的质量浓度在0.12 mg/L以内呈线性关系。荧光检测体系在激发波长373 nm和发射波长534 nm条件下进行。基于上述事实,提出了测定微量锰的荧光猝灭法。应用此法测定自来水中的Mn(Ⅱ)的含量,结果令人满意。     

高效液相色谱-荧光法测定一次性纸杯和餐盒中3种荧光增白剂的含量

建立测定一次性纸杯和餐盒中荧光增白剂含量的高效液相色谱-荧光方法。采用Inertsil ODS-3(250 mm×4.6 mm,5μm)为分析柱,以5 mmol/L乙酸铵溶液和乙腈为流动相,梯度洗脱,流速为0.5 m L/min,荧光激发波长为350 nm,发射波长为430 nm。结果表明,所选用的3种荧光增白剂(B2729、220、B2730)可以较好地被分离,回收率为77.4%~94.6%,相对标准偏差10%且线性关系良好。该法简便快捷、结果准确、灵敏度高,能够满足对一次性纸杯和餐盒中荧光增白剂含量的检测。     

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。