溴虫腈高效液相色谱分析方法的研究

对溴虫腈高效液相色谱分析方法进行了研究。用紫外检测器、C18柱,以V(乙腈)∶V(甲醇)∶V(水)=40∶40∶20为流动相,对溴虫腈的分析可取得满意的结果。该方法的相对标准偏差为0.49%,添加平均回收率为98.96%～99.39%。     

小麦中多菌灵残留量的HPLC分析方法研究

建立了小麦籽粒中多菌灵残留量的高效液相色谱测定法。样品以甲醇提取,二氯甲烷萃取净化,以Lichrospher C18柱(粒径5 mm,4.6mm×250 mm)进行分析,流动相(V甲醇∶V水= 50∶50)流速为1 mL/min时,多菌灵保留时间7.237min。本方法最低检测限为15 g/kg,加标回收率为88%~109%,变异系数4.718%~9.242%。     

杀虫剂哌虫啶的高效液相色谱分析

本文建立了一种高效液相色谱法测定哌虫啶的定量分析方法。该方法采用Agilent ZORBAX SB-C18色谱柱,以V(乙腈)∶V(甲醇)∶V(水)=20∶30∶50三元混配体系作为流动相,流速为1m L/min,在波长354 nm下,对哌虫啶进行定量分析。结果表明:该分析方法的线性回归方程为y=44.834x-306.49,相关系数r为0.9999,平均回收率为99.83%,标准偏差为0.013,变异系数为0.0133%。该方法简便快捷,准确度高,线性关系良好。     

丁吡吗啉的高效液相色谱分析

采用反相高效液相色谱法对丁吡吗啉进行了定量分析研究,流动相为V(甲醇)∶V(乙腈)∶V(水)=30∶30∶30,使用ODSC18为填料的不锈钢柱和具可变波长的紫外检测器。该方法的平均回收率为100.2%,变异系数为0.12%,标准偏差为0.12。     

33.5%甲磺·异丙·莠悬浮剂含量的测定

采用高效液相色谱,以C18为固定相,以V(甲醇)∶V(水)=50∶50(用磷酸调pH=3)为流动相,检测波长220 nm及氢火焰离子化检测器气相色谱相结合的方法,对33.5%甲磺.异丙.莠悬浮剂进行定量分析。结果表明,甲基磺草酮、异丙草胺、莠去津线性相关系数分别为0.9993,0.999 1,0.999 6;变异系数分别为0.62%,0.34%,0.51%;平均回收率分别为99.4%,99.7%,99.7%。该方法简便、快捷,准确。     

斑蝥黄含量检测方法的改进

高效液相色谱法检测斑蝥黄含量所用的流动相由甲醇∶二氯甲烷=85∶15(V∶V)代替乙腈∶甲醇∶二氯甲烷=70∶20∶10(V∶V∶V),改动流动相后斑蝥黄在1.62~16.2μg·mL-1范围内呈良好的线性关系(r=0.9998);平均回收率为99.8%(RSD=0.24%,n=9);重复性试验测得的精密度为0.24%(n=6);检测限为0.81 ng、定量限为1.33 ng。该方法灵敏、准确、专属性好,可用于斑蝥黄的含量测定。     

柱前衍生化-手性固定相法拆分2-甲基哌嗪对映体

以2,4-二硝基氟苯为衍生化试剂,建立柱前衍生化结合手性固定相高效液相色谱法拆分2-甲基哌嗪对映体的方法。采用Chiralpak IA(250 mm×4.6 mm,5μm)手性色谱柱,流动相为V(正己烷)∶V(无水乙醇)∶V(二乙胺)=50∶50∶0.1,检测波长261 nm,流速0.5 mL/min,柱温30℃。在此优化试验条件下,衍生后的对映体分离度达3以上,在0.15～1.5μg/mL浓度范围内线性关系良好,连续重复进样6次,相对标准偏差(RSD)在0.15%以下。该方法灵敏度高,重复性好,可用于2-甲基哌嗪异构体的质量控制。     

固化剂中游离MDI的高效液相色谱分析

建立了反相高效液相色谱法测定固化剂中游离MDI含量的方法。以异丙醇为衍生剂进行柱前衍生化,选用Waters XTerra C18,5μm,3.9mm×150mm色谱柱,乙腈—水为流动相,V(乙腈)∶V(水)=50∶50,检测波长为254nm。在5～50μg/mL范围内,4,4'-MDI、2,4'-MDI的回归方程相关系数均大于0.999,固化剂中4,4'-MDI、2,4'-MDI添加回收率在102.3%～109.9%。按样品测定方法平行测定5次,2,4'-MDI、4,4'-MDI峰面积的相对标准偏差(RSD)分别为0.74%、0.49%。该法测定固化剂中游离MDI具有良好的准确性和精密度。     

二氯异丙虫酰胺的高效液相色谱分析

建立了二氯异丙虫酰胺的高效液相色谱分析方法。样品用乙腈溶解,采用Agilent TC-C18柱为色谱柱,V（乙腈）∶V（水）=50∶50为流动相,PDA检测器在245 nm对二氯异丙虫酰胺进行高效液相色谱分离和检测。方法在13.6～680μg/mL的浓度范围内线性关系良好,线性回归方程为y=22 659x-15 086,相关系数R2=0.999 9,变异系数为0.37,平均回收率为99.9%。该方法简单可靠,精密度及准确度符合定量分析要求,可用于二氯异丙虫酰胺的定量分析。     

高效液相色谱法同时测定化妆品中15种防晒剂

优化和改进了《化妆品卫生规范》(2007年版)规定的测定化妆品中15种防晒剂的高效液相色谱法。样品经V(甲醇)∶V(四氢呋喃)∶V(水)∶V(0.067%高氯酸)=250∶450∶300∶0.2的混合溶液提取后,使用Kromasil C18色谱柱分离,以甲醇、四氢呋喃和0.067%高氯酸的混合溶液为流动相进行梯度洗脱,流速1 m L/min,检测波长311 nm。结果表明:在给定的质量浓度范围内15种防晒剂的峰面积与质量浓度呈良好的线性关系,方法回收率为85.6%~115.9%,检出限为0.8~12.5 ng。     

Nanoclay distribution and its influence on the mechanical properties of rubber blends

The distribution of modified and unmodified nanoclays inside the rubber phases of immiscible rubber–rubber blends composed of nonpolar–polar natural rubber (NR)/epoxidized natural rubber (ENR) and nonpolar–nonpolar NR/polybutadiene rubber (BR) was investigated for the first time. The distribution of clays at various loadings in the blends was calculated from the viscoelastic properties of the blends. For example, in the 50 : 50 NR/ENR blend, 42% Cloisite 30B migrated to the NR phase, and 58% went to the ENR phase. However, in the same blend, only 7% Cloisite Na⁺ was found in the NR phase, and 93% was found in the ENR phase. Again, in the 50 : 50 NR/BR blends, the NR phase contained 85% Cloisite 30B, whereas 55% Cloisite Na⁺ migrated to the NR phase. All these observations were explained with the help of viscosity, X‐ray diffraction, and morphology analyses. The effect of the distribution of the clay on the mechanical properties was also discussed. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

氟吗啉水分散片剂高效液相色谱分析方法

采用高效液相色谱法外标法定量分析氟吗啉水分散片剂。该方法以甲醇＋水（50＋50）作为流动相,流速为0．5ml／min,C18反相色谱柱,柱温为25℃,检测波长为230nm。本方法的回收率大于99％,变异系数小于0．3％。     

Crosslinking of polypropylene–polyethylene blends by peroxide and the effect of pentaerythritol tetrallyl ether

Crosslinking of polypropylene–polyethylene (PP-PE) blends involving 10, 20, 30, 40, 50, 60, 70, 80, and 90% of PP with dicumylperoxide (DCP) or tert-butyl perbenzoate (TBPB) and in the presence of coagent pentaerythritol tetrallyl ether (PETA) was investigated at 180°C. It was found that at lower concentrations of peroxide alone (e.g., 2.5% of DCP) only PE component is crosslinked in all compositions of PP-PE blends. In the crosslinking of PP-PE 50:50 with 4% of TBPB, insoluble gel was obtained, which contained 13% PP and 87% PE. If 2% PETA was also used, the portion of PP in gel increased to 39%; the total yield of gel in PP-PE blend increased from 50 to 70%. The lower crosslinking efficiency of coagent PETA in the PP-PE blends compared with PP alone is associated with better solubility of the coagent in the PE phase in contrast to the PP phase. The coagent does not particularly raise the crosslinking efficiency of peroxide in PE, but increases it in the PP phase. A remarkable decrease in melting temperature and temperature of crystallization of both polymer components depending on peroxide concentration was found by calorimetric measurements.     

Dilatation Behavior of Two Differently Heat-Treated Commercial Magnesia-Partially-Stabilized Zirconias

The dilatation behavior of two grades of partially stabilized zirconia (PSZ) was determined. ZN 40 is a material which contains 40% to 50% t -ZrO₂ particles, and has a reproducible dilatometric behavior up to 900°C. ZN 50 is a Mg-PSZ containing 20% to 30% of the monoclinic phase. The cyclic dilatation curves show an unstable hysteresis effect which arises from the tetragonal-monoclinic phase transformation.     

Heterogeneous network polymers. IV. Dynamic mechanical properties—composition—phase structure relationships

Heterogeneous network polymers were prepared from poly(D -glutamic acid) (PGA) and poly(oxyethylene glycol) (PEG). The content of PGA was systematically varied: 30%, 40%, 50%, 60%, 65%, and 70% by weight. The molecular weights of the crosslinking PEG were 300, 600, 900, and 1800. The plots of the dynamic mechanical tan δ peak temperatures, the PGA interhelical distances (x-rays) and the densities against PGA contents showed a distinct break between 50% and 60%. The photographs under polarizing microscope also indicated an occurrence of phase inversion in the above content region. PGA containing small amounts of PEG and PEG containing small amounts of PGA were found to constitute the continuous phases, respectively, above and below the phase inversion region, while a well-mixed phase is always the dispersed phase. The glass transition was ascribed to the micro-Brownian motions of PGA, PEG, and PEG above and below the phase inversion region, respectively.     

Natural rubber/nitrile butadiene rubber/hindered phenol composites with high-damping properties

New natural rubber (NR)/nitrile butadiene rubber (NBR)/hindered phenol (AO-80) composites with high-damping properties were prepared in this study. The morphological, structural, and mechanical properties were characterized by atomic force microscopy (AFM), polarized Fourier transform infrared spectrometer (FTIR), dynamic mechanical thermal analyzer (DMTA), and a tensile tester. Each composite consisted of two phases: the NR phase and the NBR/AO-80 phase. There was partial compatibility between the NR phase and the NBR/AO-80 phase, and the NR/NBR/AO-80 (50/50/20) composite exhibited a co-continuous morphology. Strain-induced crystallization occurred in the NR phase at strains higher than 200%, and strain-induced orientation appeared in the NBR/AO-80 phase with the increase of strain from 100% to 500%. The composites had a special stress–strain behavior and mechanical properties because of the simultaneous strain-induced orientation and strain-induced crystallization. In the working temperature range of a seismic isolation bearing, the composites (especially the NR/NBR/AO-80 (50/50/20) composite) presented a high loss factor, high area of loss peak (TA), and high hysteresis energy. Therefore, the NR/NBR/AO-80 rubber composites are expected to have important application as a high-performance damping material for rubber bearing.     

聚钛硅氧烷的溶胶-凝胶合成及转变规律研究

以甲基三甲氧基硅烷和钛酸四丁酯为原料、甲醇为溶剂、盐酸为催化剂采用溶胶-凝胶法制备了含有杂原子钛的甲基硅树脂基体，借助傅立叶变换红外光谱研究了其特性。为了全面地了解该体系的溶胶-凝胶转相规律，我们分别做出了加水量为理论水解量30％、40％、50％时体系的转相相图，并将其转换为直角坐标以考察加水量、甲醇用量对相转变的影响a结果表明，选用反应条件为：甲醇用量大于70％、水用量小于40％、反应温度为50℃、盐酸用量为10％时，容易形成含钛量大于50％的溶胶状态的甲基硅树脂。     

雷公藤次碱的高效液相色谱分析方法

雷公藤的根皮提取物中一般含有多个具杀虫活性的生物碱,其中以雷公藤次碱的活性最高。采用高效液相色谱法,乙腈 0．02mol/L磷酸二氢钾水溶液(50 50)作为流动相,流速为1ml／min,C18反相色谱柱,紫外检测波长为195nm,用外标法对提取物中的雷公藤次碱进行了定性定量分析,方法的变异系数为0．24％,线性相关系数为0．9995,平均回收率为99．8％。     

CR/PVC共混物的相容性与形态结构的研究

通过红外光谱和透射电子显微镜对CR/PVC的溶液共混物、熔体共混物和乳液共混物的相容性及形态结构进行了研究。结果表明,CR/PVC共混物是热力学不相容体系。在溶液和熔体共混物中,当PVC含量分别为60％—70％和60％左右时产生相反转;在乳液共混物中,PVC以乳液粒子的形式分散在 CR基体中,当 PVC含量为 50％时,CR仍以连续相存在。