食品中农药残留检测技术研究进展

介绍了国内外农药残留检测技术研究进展,阐述了食品、农产品中农药残留的提取、浓缩及净化技术,探讨了农药残留检测的气相色谱、液相色谱、色质联用技术以及确证技术,并对农药残留检测技术的研究及应用进行了展望。     

农药残留检测技术研究进展

文章介绍了国内外农药残留检测技术研究进展,阐述了食品、农产品中农药残留的提取、浓缩及净化技术,探讨了农药残留检测的气相色谱、液相色谱、色质联用技术以及确证技术,并对农药残留检测技术的研究及应用进行了展望。     

气相色谱-质谱联用测定水果和蔬菜中哒螨灵残留量

建立气相色谱-质谱联用测定水果和蔬菜中哒螨灵农药残留量的检测方法.样品经过提取、净化、浓缩后,用气质联用进行检测.方法的检出限0.05 mg/L,样品中哒螨灵的平均添加回收率在79.7%～89.5%之间,变异系数在3.21%～4.78%之间.     

光谱法检测农药残留量的研究进展

综述了近十年来国内外基于光谱法对农药残留量进行检测的研究进展。讨论了分光光度法、红外光谱法、紫外可见光-分光光度法、荧光光谱法、化学发光法等光谱分析方法,对各种方法的特点进行了比较和评述。     

分散固相净化-气相色谱法检测蔬菜中氟吡菌胺等15种农药残留

建立了分散固相净化-气相色谱法同时检测蔬菜中氟吡菌胺、唑菌酮和茚虫威等15种残留农药的分析方法。样品经乙腈提取、分散固相法净化后用气相色谱仪ECD检测。当添加浓度在0.05~1.0 mg/kg时,各种农药的回收率在63.6%~111.9%之间,相对标准偏差为0.9%~17.6%,最低检测浓度为0.005~0.030 mg/kg。该方法可用于蔬菜中残留农药的快速筛查。     

有机磷农药多残留检测方法的研究进展

建立高效快速的有机磷农药多残留检测方法是近年农药残留检测的一个热点.在多残留检测领域,仪器分析法和酶抑制法发挥着越来越重要的作用,而免疫分析法、生物传感器分析法成为新兴的检测方法.综述了上述有机磷农药多残留检测方法的研究进展,并对发展方向进行了展望.     

中药材农药残留分析中的前处理方法比较

[目的]比较中药萝芙木中17种农药残留的2种前处理技术。[方法]样品经有机溶剂提取后,采用磺化法和固相萃取法进行净化,并采用GC-ECD进行检测,对前处理的提取条件和净化条件进行优化。[结果]石墨炭黑/氨基(CARBON/NH2)复合固相萃取小柱能够较好地去除杂质,磺化法不适用硫丹(含硫丹Ⅰ和硫丹Ⅱ)、狄氏剂和拟除虫菊酯类农药。[结论]采用CARBON/NH2复合固相萃取技术的方法平均回收率为75.11%~113.53%,相对标准偏差为0.34%~4.84%,适合中药萝芙木中17种农药残留的分析。     

磁性分散固相萃取/ECD-GC同时检测家禽、畜肉中有机氯和菊酯类农药残留

建立了采用气相色谱法对家禽、畜肉样品中的有机氯和菊酯农药残留进行同时检测的方法。样品经过一种新型的磁性分散固相萃取技术——Fe_3O_4/AMWNTs磁性材料进行超声提取、乙腈解析20 min、净化以及浓缩,然后进行气相色谱-电子捕获检测器分析,外标法定量。结果表明农药残留的分离度好,线性关系良好,相关系数均大于0. 999,相对标准偏差(RSD)5%,实际样品检出率在75%～95%之间。此方法灵敏度高、操作快速、简便、净化彻底,回收率在94. 5%～99. 2%之间,结果令人满意,方法可适用于肉类产品中有机氯和菊酯类农药残留的筛查及定量检测。     

HPLC-MS/MS技术检测稻田土、水中阿维菌素等5种农药

建立了稻田土和水中阿维菌素等5种农药残留的高效液相色谱-串联质谱检测方法。稻田土采用乙腈振荡提取,稻田水采用二氯甲烷液液萃取,无需净化,直接过膜后检测。结果表明:阿维菌素、氯虫苯甲酰胺、噻嗪酮、嘧菌酯、茚虫威在0.005~1.0 mg/L质量浓度范围内线性关系良好,相关系数0.99;稻田土和水中5种农药回收率范围分别为82.89%~118.12%、87.55%~110.69%;变异系数范围分别为0.95%~7.36%、1.12%~9.37%。该方法操作简单,快速准确,满足农药残留分析的要求。     

农药残留检测的技术研究进展

综述了近年来农药残留检测技术的研究进展,其检测方法主要有色谱法、色谱一质谱法、光谱法、酶抑制法和毛细管电泳法,并展望了这一领域的发展趋势。     

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.     

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.     

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.     

Novel polyurethane coating technology through glycidyl carbamate chemistry

Glycidyl carbamate chemistry combines the excellent properties of polyurethanes with the crosslinking chemistry of epoxy resins. Glycidyl carbamate functional oligomers were synthesized by the reaction of polyfunctional isocyanate oligomers and glycidol. The oligomers were formulated into coatings with several amine functional crosslinkers at varying stoichiometric ratios and cured at different temperatures. Properties such as solvent resistance, hardness, and impact resistance were dependent on the composition and cure conditions. Most coatings had an excellent combination of properties. Studies were carried out to determine the kinetics of the curing reaction of the glycidyl carbamate functional oligomers with multifunctional and model amines. Detailed kinetic analysis of the curing reactions was also undertaken. The results indicated that the glycidyl carbamate functional group is more reactive than a glycidyl ether group. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, on October 27–29, 2004, in Chicago, IL.