快速测定化学需氧量(CODCr)方法探讨

探讨了化学需氧量(CODCr)热消解快速测定法的测试条件。建立的方法通过对雨水、生活污水和工业废水的化学需氧量(CODCr)测试考察,有95%的把握认为本方法的测试结果与国标法的结果无显著差异,即二者的测试结果吻合、一致。建立方法测试的精密度达到国标法的要求,消解时间从原来的2 h缩短到10 min左右,能够省时、准确、快速地分析,提高了工作效率,同时节约能源。     

洗面奶微波消解处理条件的正交试验设计优化

建立了洗面奶微波消解处理条件的优化方法,通过L9(34)正交试验设计,优化了微波消解洗面奶过程中的3个主要影响因素,得到合适的处理条件为:以5 mL硝酸消解0.5 g洗面奶,消解时间为10 min,消解温度为150℃。结果表明,在此处理条件下,对不同样品检测的回收率为94.12%～104.26%,相对标准偏差为0.68%～2.03%。     

电感耦合等离子体质谱法测定洗涤用品中14种重金属

采用微波消解法预处理洗涤用品,使用压力控制装置对消解过程进行监控并对消解条件进行摸索,考察了消解量、消解体系、消解温度和保持时间对消解结果的影响,优化选择了电感耦合等离子体质谱法(ICP-MS)的测定参数和内标元素。建立了微波消解-电感耦合等离子体质谱法测定洗涤用品中14种重金属的检测方法。方法检出限在0.002~0.362μg·L-1,回收率在90.8%~109.6%,相对标准偏差小于10%。     

微波消解-ICP-MS筛选法对PVC塑料制品中有机锡的测定

建立了微波消解-电感耦合等离子体质谱仪(ICP-MS)筛选法测定PVC塑料制品中有机锡的方法。采用6 m L硝酸+2 m L双氧水+1 m L氟硼酸消解体系,在190℃下消解30 min可使PVC塑料制品消解完全。本方法可实现有机锡的快速筛选,方法的检出限(3σ)为0.5 mg/kg。加标回收率在85.07%~112.09%之间,测定值的相对标准偏差(n=7)在2.8%~5.5%。     

石墨消解-气相分子吸收光谱法用于土壤全氮快速测定

建立了一种基于石墨消解-气相分子吸收光谱法快速测定土壤样品中全氮的方法。对样品取样量、石墨消解时间控制、重铬酸钾-硫酸消解溶液用量等实验影响要素进行了研究，得出最优实验参数是土壤取样量在0.050 0～0.100 0 g、消解时间在8～10 min以及7～10 mL的重铬酸钾-硫酸消解溶液。在此实验参数下，方法的相对标准偏差为3.8%～6.6%,检出限为50 mg/kg,加标回收率为89.3%～98.1%。本方法通过测量3个国家土壤标准物质，并与凯氏法测定土壤全氮进行对照，结果表明两种方法间无显著性差异。该方法采用石墨消解前处理后，消解液直接上机检测，简便快捷，定量准确，重现性好，适用于大批量土壤中全氮的测定。     

应用全自动间断化学分析仪测定婴幼儿配方乳粉中的磷含量

目的:建立全自动间断化学分析仪法测定婴幼儿配方乳粉中的磷含量。方法:采用湿法消解样品,以钒钼酸铵作为显色剂,通过全自动间断化学分析仪(λ=420 nm)自动测定磷含量。结果:磷含量浓度在1.50～15.0 mg/L范围内呈良好线性关系(r=0.9999);低、中、高3个浓度的平均回收率分别为89.8%、93.9%、98.4%;精密度(RSD)分别为1.4%、2.4%;本方法与国标方法的检测结果一致。结论:本方法操作简单、试剂用量少,可用于婴幼儿配方乳粉中磷含量的测定。     

氯离子去除法测定高氯废水化学需氧量的研究

机械式蒸汽再压缩技术(MVR),由于其高效节能的特点,在废水蒸发中应用越来越广泛。含氯化钠的废水经MVR蒸发后,浓缩液中氯离子质量分数10%,严重干扰采用重铬酸钾法测定化学需氧量(COD)。为了消除高含量氯离子对COD测定的干扰,在高氯废水中加入硫酸溶液,加热将其中的氯离子以氯化氢形式挥发,再测定COD。将某废水经MVR蒸发浓缩液(氯质量分数为13%)和加入硫酸溶液(体积分数为80%)到COD消解管中,并用COD消解装置加热除氯。结果表明,该方法能够将高氯废水中的氯离子去除至1 000mg/L,满足了重铬酸钾法测定COD标准检测方法对样品中氯离子含量的要求。采用该方法分别测定COD 100mg/L标样(氯质量分数为9%)、某废水MVR蒸发浓缩液样品(氯质量分数为13%)和MVR蒸发浓缩液经无害化处理后的样品(氯质量分数为8%)。结果表明,该方法具有良好的准确度和精密度,成功建立了氯离子质量分数为13%的高氯废水COD的快速测定方法。该方法直接利用COD消解装置进行氯离子去除,再进行快速密闭消解法测定COD,操作简单、快速。     

微塑料检测分析技术研究进展

系统介绍了微塑料的分离技术(密度分离、淘析法和油提法),消解技术(酸消解、碱消解、氧化消解、酶消解和UTS法)以及检测技术(目检法、光谱分析法和热分析法),并对其优缺点进行了对比分析。通过对目前研究进展的总结分析,认为不同的分离、消解及检测技术都会导致微塑料丰度、化学信息、形貌特征的差异,从而使得不同研究结果难以进行横向比较,影响了对微塑料环境行为、污染现状和时空分布等研究。提出未来应建立统一的、标准化的微塑料预处理及检测技术,更应关注图像分析与传统检测方法的联合应用,通过机器学习,为微塑料研究提供更快捷、精准的检测分类技术。     

ICP-OES法测定镍基合金中9种微量元素

建立了ICP-OES(等离子体发射光谱法)测定镍基合金中9种微量元素的测试方法。采用3∶1体积比浓盐酸和浓硝酸混酸通过微波消解仪消解0.2 g样品制备样品溶液。标准溶液通过基体匹配法制备,各元素标准曲线线性相关系数大于0.999。本方法各元素的方认检测限在0.004 mg/L到0.30 mg/L之间。应用本方法进行测试,9种元素的相对标准偏差(n=7)均小于5%,加标回收率在95.0%到102.7%之间。实验结果表明本方法精密度好、准确度高,满足日常分析的要求。     

精喹禾灵在掌叶半夏块茎和土壤中的残留分析及土壤中的消解动态

[目的]为检测精喹禾灵在掌叶半夏中的残留及土壤中的消解动态,建立了精喹禾灵在掌叶半夏及土壤中的分析方法。[方法]采用高效液相色谱法检测了不同剂量8.8%精喹禾灵乳油处理后在掌叶半夏块茎中的残留量,并分析了其在土壤中的消解动态。[结果]建立了精喹禾灵在掌叶半夏及土壤中残留量检测方法,在添加质量分数为0.05、0.1、0.5 mg/kg时,平均回收率为87.3%~92.5%,相对标准偏差(RSD)为3.63%~4.12%。精喹禾灵在掌叶半夏及土壤中最低检测质量分数为0.05 mg/kg。田间试验结果表明:精喹禾灵在土壤中消解较快,半衰期为5.40 d。施药后第28天和第215天,土壤和掌叶半夏块茎中均未检测到精喹禾灵。[结论]建立的掌叶半夏块茎中精喹禾灵残留量的检测方法操作简单、准确性高,可用于掌叶半夏块茎中精喹禾灵残留检测,精喹禾灵用于掌叶半夏种植中化学除草较为安全。     

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。