气相色谱测定饮料中甜蜜素方法的改进

为提高气相色谱法测定饮料中甜蜜素的检测效率,通过减少待测样品的取样量,同时减少相应的试剂使用量,采用15 m L离心管代替国标的50 m L离心管做容器,利用回旋振荡器一次性同时震荡萃取代替人工逐个萃取操作,使样品处理得到简化和统一化,大大节省了样品前处理所需的时间。改进后检测限0. 0040 mg/kg,RSD=2. 44%,回收率在80%～110%之间。满足原国标方法的检测要求,且RSD更小。     

离子色谱法检测污水中总氮含量的研究

建立离子色谱法检测污水中总氮含量的方法。样品消解后,经高效阴离子交换柱分离,抑制型电导检测器检测。结果显示:经处理后的污水样品中硝酸根的回收率为95.76%~104.74%,样品5次测定结果相对偏差为0.45%~1.25%。认为此方法能够消除污水中干扰硝酸根测定的杂质及干扰物质对总氮含量测定结果的影响,减小由于过硫酸钾的纯度问题对检测结果造成的干扰。比较污水水样处理前测定的铵态氮、硝态氮的含量与处理后的总氮含量,可以得出其结果符合理论增长趋势。     

碱预处理糠醛渣性质及其纤维素酶解研究

以糠醛渣为原料进行碱法预处理,对比了处理前后的样品成分、结晶度、表面特性、红外谱图的变化以及对纤维素酶解的影响。研究结果表明:经NaOH处理样品,木质素脱除量随着温度升高而增加,120 ℃ 处理后的样品木质素脱除了 10.22 %,而碱性过氧化氢处理样品木质素脱除率达到 12.6 %。NaOH预处理后的样品酶解糖化率随处理温度的升高而降低。每克纤维素加入纤维素酶 12 FPU、纤维二糖酶 15 IU,120 ℃ 经NaOH预处理样品,酶解 72 h 后糖化率为38.6%,比原料糠醛渣低21.0个百分点,而经 60 ℃,6 h 碱性过氧化氢处理后的样品,酶解 72 h 糖化率可达到 86.6 %,比原料糠醛渣高27.0个百分点。NaOH预处理后样品红外谱图检测,证明生成了新的醚键。碱法预处理后的样品结晶度要比未处理的样品的稍高,且表面更加光滑。     

微波消解-原子荧光光谱法测定洗发水中二硫化硒

采用微波消解-原子荧光光谱法与差减法相结合的方法测定洗发水中二硫化硒。标准曲线浓度在0～10μg/L线性良好、相关系数r=0.999 9,方法的检出限为0.169 2μg/kg,加标回收率在90.44%～95.73%,精密度为1.51 %,对实际样品测试的准确度在90.11%～95.26%。该方法的样品前处理简便、测定效率高,能提高日常检测的效率,可用于大批量样品的检测。     

两种测定生物制品宿主细胞DNA残留量方法的建立

目的建立特异性强、检测限低、准确度高的生物制品中宿主细胞DNA残留量的检测方法。方法通过优化,提高磁珠分离法和化学沉淀法提取样品中残留DNA的准确度,再利用Taqman探针法对样品和标准DNA进行定量PCR(quantitative PCR,q PCR)检测,分析样品中DNA残留量。对建立的两种检测体系进行专属性、精密度、准确度、耐用性验证,并确定两种方法的检测限和定量限。结果建立的q PCR体系标准曲线的相关系数(R2)均高于0. 99,能特异性地检测CHO细胞DNA,对其他种属DNA无扩增反应。不同DNA加标量样品的DNA回收率相近,均值均在60. 0%～140. 0%,3次测定的相对标准偏差(RSD)均小于30%。不同的退火温度反应条件下,RSD不大于30%。基于磁珠分离法的qPCR检测体系能检测出DNA残留浓度为5 pg/m L的DNA样品,定量限可达10 pg/mL;基于化学沉淀法的qPCR检测体系能检测出DNA残留浓度为0. 125 pg/m L的DNA样品,定量限可达1. 5 pg/mL。结论建立并优化了两种准确测定生物制品宿主细胞DNA残留量的处理样品方法,其中化学沉淀法检测限和定量限较低,更适合低浓度生物制品的样品处理。     

高效液相色谱法检测水中的灭草松

使用高效液相色谱法对水源水、出厂水、管网水中的灭草松进行检测。采用固相萃取技术对1 000 mL样品进行前处理,处理后的样品氮吹浓缩为1 mL后进行分析。本方法检出限为0.0001 mg/L,相对标准偏差RSD在2%内,回收率在80%～93%间。与生活饮用水卫生标准（GB/T5750-2006）相比,此方法不需要进行繁琐的液液萃取和衍生操作,较为简单,并且能满足日常的检测分析。     

土壤中挥发酚的测定

土壤样品用水提取后再蒸馏法进行前处理,然后用4-氨基安替比林萃取分光光度法测定。本方法最低检测量为0.5μg,具有灵敏度高、精密度好的特点,加标回收率为86.7%～95.3%,对测定地质环境样品结果令人满意。     

化学检测样品处理技术研究

样品处理是化学检测中难度大,且耗时费力的一项工作,做好样品处理工作,是样品进行仪器分析的基础和关键。本文中,作者首先深入探讨了化学检测中样品处理技术的地位及其难点,并分析了化学检测样品处理需要遵循的原则,最后,讨论了化学检测样品处理技术的现状。     

原子荧光法测定土壤和沉积物中汞元素的混合酸消解方法研究

利用酸组分试剂的不同组合研究测定土壤和沉积物中汞元素的消解条件,并探讨在不同土壤和沉积物样品之间所产生的差异,针对酸组分对不同样品的差异确定土壤样品中差异成分的适合条件。结果表明:当样品质量为(0.2000±0.50%)g时,土壤和沉积物消解的酸组分最佳组合为逆王水法的盐酸:硝酸:过氧化氢=1:3:1,各消解法的处理效率(n=5):水浴法时间可缩短为1.0 h,准确度(回收率)达93.1%,精密度(RSD)为1.35%;电热板法因处理时间长且回收率不佳,不建议采用(准确度为80.5%,RSD为13.3%);微波法处理的总时间为1.0 h,回收率为92.4%,但精密度稍差为9.32%,因此选用水浴法进行真实样品测定。此优化的消解方法能直接应用于多种真实样品的前处理,并能简便地利用同一酸组分条件快速测定土壤和沉积物类型的样品,为环境污染监测检测行业提供参考依据。     

银翘解毒丸中有机氯农药残留测定前处理方法的比较与分析

建立了测定银黄解毒丸有机氯农药残留量的新方法。对银翘解毒丸中的有机氯农药残留进行预处理分析方法研究。通过优化不同溶剂、提取方法、提取剂和净化剂预处理样品,确定最佳前处理方法。选择最佳处理方法对银翘解毒丸进行气相色谱检测。9种有机氯农药的检出限为0.000 1~0.01 mg/kg,相对标准偏差(RSD)为13.7%~18.7%,回收率86.2%~110.4%。针对市场随机抽取30多种样品进行检测,测定结果显示,大部分样品中有机氯农残未检出,少部分含量在0.1 mg/kg以下,极少数样品有机氯农残含量超过国家标准。与传统方法相比较,该方法具有更高的灵敏度和准确度,并且快捷有效,更适合于银翘解毒丸的有机氯农药残留检测。     

Many Drugs of Abuse May Be Acutely Transformed to Dopamine,Norepinephrine and Epinephrine In Vivo

It is well established that a wide range of drugs of abuse acutely boost the signaling of the sympathetic nervous system and the hypothalamic–pituitary–adrenal (HPA) axis, where norepinephrine and epinephrine are major output molecules. This stimulatory effect is accompanied by such symptoms as elevated heart rate and blood pressure, more rapid breathing, increased body temperature and sweating, and pupillary dilation, as well as the intoxicating or euphoric subjective properties of the drug. While many drugs of abuse are thought to achieve their intoxicating effects by modulating the monoaminergic neurotransmitter systems (i.e., serotonin, norepinephrine, dopamine) by binding to these receptors or otherwise affecting their synaptic signaling, this paper puts forth the hypothesis that many of these drugs are actually acutely converted to catecholamines (dopamine, norepinephrine, epinephrine) in vivo, in addition to transformation to their known metabolites. In this manner, a range of stimulants, opioids, and psychedelics (as well as alcohol) may partially achieve their intoxicating properties, as well as side effects, due to this putative transformation to catecholamines. If this hypothesis is correct, it would alter our understanding of the basic biosynthetic pathways for generating these important signaling molecules, while also modifying our view of the neural substrates underlying substance abuse and dependence, including psychological stress-induced relapse. Importantly, there is a direct way to test the overarching hypothesis: administer (either centrally or peripherally) stable isotope versions of these drugs to model organisms such as rodents (or even to humans) and then use liquid chromatography-mass spectrometry to determine if the labeled drug is converted to labeled catecholamines in brain, blood plasma, or urine samples.     

Sapindaceae,cyanolipids, and bugs

Scentless plant bugs (Heteroptera: Rhopalidae) are so named because adults of the Serinethinae have vestigial metathoracic scent glands. Serinethines are seed predators of Sapindales, especially Sapindaceae that produce toxic cyanolipids. In two serinethine species whose ranges extend into the southern United States,Jadera haematoloma andJ. sanguinolenta, sequestration of host cyanolipids as glucosides renders these gregarious, aposematic insects unpalatable to a variety of predators. The blood glucoside profile and cyanogenesis ofJadera varies depending on the cyanolipid chemistry of hosts, and adults and larvae fed golden rain tree seeds (Koelreuteria paniculata) excrete the volatile lactone, 4-methyl-2(5H)-furanone, to which they are attracted.Jadera fed balloon vine seeds (Cardiospermum spp.) do not excrete the attractive lactone. Loss of the usual heteropteran defensive glands in serinethines may have coevolved with host specificity on toxic plants, and the orientation ofJadera to a volatile excretory product could be an adaptive response to save time.Mention of a commercial product does not consititute an endorsement by the USDA.     

2008～2009年世界塑料工业进展

收集了2008年7月～2009年6月世界塑料工业的相关资料,介绍了2008～2009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、环氧树脂、不饱和聚酯树脂)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。     

ICP-MS法测定地球化学样品中As、Cr、Ge、V等18种微量痕量元素的研究

建立了测定地球化学样品中包括As、Cr、Ge、V等18种微量、痕量元素的ICP-MS方法。地化试样用HF-HNO3混酸分解后,以1 1 HNO3溶解干渣。由于制样不使用盐酸,避免了Cl对As、Cr、Ge、V的质谱干扰。用国家一级地球化学标准物质GBW 07309制备溶液优化仪器工作参数,并用于校准。方法测定限(6s)为:0.007~6.4μg/g,精密度(RSD%,n=12)为:29%~9.4%,经过国家一级地球化学标准物质的分析验证,结果与标准值吻合。方法已应用于国土资源调查的试样分析。     

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.