食品中苏丹红1号的GC-MS/SIM快速分析方法研究

采用气相色谱-质谱(GC-MS)选择离子检测法(SIM),提出一种测定食品中苏丹红1号的新方法。色谱柱30m×0.25mmPR-SR石英毛细管柱,进样口温度280℃,柱温200℃,10℃/min升至280℃;柱前压100kPa,载气He;EI离子源,选择m/z77、115、143、248离子用于SIM检测,并根据这4个抽出离子的峰面积比进行确证。苏丹红1号的线性范围为0.01～10.0mg/L,相对标准偏差小于6.1%,回收率85%～90%,检出限为0.001mg/kg,每个样品分析时间为5min。本法与欧洲健康与消费者保护委员会发布的方法(HPLC法)相比灵敏度高两个数量级,分析时间缩短,用色谱保留时间、质谱同时定性,消除了食品中杂质的干扰,避免了只用色谱保留时间定性可能产生的假阳性,结果准确可靠,选择性和重复性好,适用于所有食品成品及原料的检验。

THE SYNTHESIS OF NEW POLED CROSSLINKED POLYMETHACRYLATES AND THEIR SECOND ORDER NONLINEAR OPTICAL PROPERTIES

Films were prepared from mixtures of copolymers of 4-nitro-4'-[N-methylacryloyloxyethyl, N'-ethyl] amino azobenzene with glycidyl methacrylate (chromophore content: 6 mol%) and copolymers containing anhydride units, which was obtained by the reaction of 4-nitro-4'-[N-hydroxyethyl, N'-ethyl] amino azobenzene with polymethacryloyl chloride (chromophore content: 25 mol %). During thermal poling process the anhydride reacts with the epoxy group and the resulting crosslinked network structure will stabilize the second harmonic generation in the poled film. The second harmonic generation of the poled film shows a maximum with the variation of composition this is presumed to be due to the effects of the increasing of concentration, orientation order as well as orientation stability of chromophore groups during crosslinking.

Properties of DR1/PMMA-co-GMA for High Speed Electro-optical Switch

A non-linear optical（NLO） material was synthesized by means of a simple method.This material can be applied in electro-optical（EO） devices,such as EO switches and modulators.The Disperse Red 1（DR1） was doped in polymethyl-methacrylate-co-glycidyl methacrylate（PMMA-co-GMA） as the NLO active chromophore.The synthesis process and material structure were expressed.The thermal properties,surface morphology and optical characteristics of the material were investigated by means of differential scanning calorimetry（DSC）,thermogravimetric analysis（TGA）,atomic force microscopy（AFM）,and m-lines technique.Using the reflection technique,the value of the electro-optical coefficient γ 33 was measured as 11 pm/V at a wavelength of 1310 nm.An EO switch with nanosecond response based on this material has been fabricated.

Digestive Rate of Dongtian F_1 Red Dear in Weaning Period and Growth Period

in this paper, 4N-HCLAIA method was adopted to conduct digestive tests in young female and male Dongtian F1 red deer (Cervus elaphus) of rearing seperatefy in growth period and mixed raising in weaning period in Harbin Specialty Research Institute. Results indicated that digestive rate of crude protein and crude fiber were 95.35% and 73.68% respectively when rational protein content was 26.8% in growth period. Digestive rate was not significantly different between female and male(P>0.05)i During weaning period, When rational crude protein content is 22.06%, digestive rate of crude protein and crude fiber were 93.05% and 63.96%, respectively. The tests suggest that higher rational protein can be effective in accelerating groWth of young Dongtian F1 red deer during growth period and weaning period(before 10 months old).

Temperature regulates negative supercoils to modulate meiotic crossovers and chromosome organization

Crossover recombination is a hallmark of meiosis that holds the paternal and maternal chromosomes(homologs)together for their faithful segregation,while promoting genetic diversity of the progeny.The pattern of crossover is mainly controlled by the architecture of the meiotic chromosomes.Environmental factors,especially temperature,also play an important role in modulating crossovers.However,it is unclear how temperature affects crossovers.Here,we examined the distribution of budding yeast axis components(Red1,Hop1,and Rec8)and the crossover-associated Zip3 foci in detail at different temperatures,and found that both increased and decreased temperatures result in shorter meiotic chromosome axes and more crossovers.Further investigations showed that temperature changes coordinately enhanced the hyperabundant accumulation of Hop1 and Red1 on chromosomes and the number of Zip3 foci.Most importantly,temperature-induced changes in the distribution of axis proteins and Zip3 foci depend on changes in DNA negative supercoils.These results suggest that yeast meiosis senses temperature changes by increasing the level of negative supercoils to increase crossovers and modulate chromosome organization.These findings provide a new perspective on understanding the effect and mechanism of temperature on meiotic recombination and chromosome organization,with important implications for evolution and breeding.

Enhancing the photoluminescence intensity of CaTiO_3:Eu^(3+) red phosphors with magnesium

Red phosphors MgxCa1-xTiO3：Eu3＋ （0〈x〈0.5） were synthesized by solid-state reaction method. The crystalline structure and morphology of the as-prepared samples were confirmed by X-ray diffraction （XRD） and scanning electron microscopy （SEM）. The luminescence property was measured using photoluminescence excitation and photoluminescence emission spectra. Results showed that spherical particles appeared in the phosphor bodies and size of the phosphor particles were tmiformly distributed in the range of 600-800 nm when the Mg2＋ concentration was about 40 mol.%. It could readily be seen that the strongest PL emission was located at 617 nm monitored at 398 nm, which well matched with the near ultraviolet （NUV, 395400 nm） GaN-LEDs. More importantly, PL emission intensity （617 nm） of phosphor Mg0.nCa0.6TiO3：0.03Eu3＋ was 4.26 times of that of phosphor CaTiO3：0.03Eu3＋ Based on these results, it implied that the PL intensity of phosphorCaTiO3：0.03Eu3＋ could be significantly enhanced by introducing Mg2＋ into CaTiO3 host lattices and the phosphor Mg0.4Ca0.6TiO3：0.03Eu3＋ might be the promising red-emitting phosphor in making tricolor phosphor converted white-LEDs.