火焰原子吸收光谱法测定羊血中铁、铜和锌3种微量元素

建立了湿法消解-火焰原子吸收光谱法对羊血中Fe、Cu和Zn 3种微量元素测定的方法.方法的校准曲线线性关系良好（r=0.9965-0.9999）,方法加标回收率（n=5）在96.2％-98.5％之间,RSD值（n=5）在1.3％-4.9％之间.为了解动物微量元素含量提供参考,也为进一步研究畜禽疾病与微量元素的相关性提供基础资料.     

微波消解-火焰原子吸收光谱法测定四大怀药中的Fe和Zn

探讨了测定四大怀药中微量元素铁和锌的新方法.用高压密闭微波消解-火焰原子吸收法测定四大怀药——怀山药、怀菊花、怀地黄、怀牛膝等怀药中微量元素Fe和Zn的含量.铁的回归方程为y=0.0968x+0.0114,r=0.9995(n=6),线性范围0-6.4μg/mL,平均回收率91.29％-101.06％,RSD为1.334％-4.314％.样品铁含量为159.091-1535.64μg/g.锌的回归方程为y=0.4207x+0.0039,r=0.9996(n=6),线性范围0-1.2μg/mL,平均回收率93.58％-100.85％,RSD为1.145％-3.634％.样品锌含量43.571-70.357μg/g.微波消解法消解样品,具有省时、简便、经济、消解完全、污染少等特点,可用于怀药微量元素的测定.     

紫外分光光度法测定姜黄素磺丁基醚-β-环糊精包合物的含量

建立测定姜黄素磺丁基醚-β-环糊精包合物中利福平含量的方法.采用紫外分光光度法测定含量,测定波长为426nm.姜黄素在426nm处有最大吸收,在1.05-7.35μg/mL范围内与吸光度呈良好的线性关系,回归方程为:A=0.1309C+0.0306(r=0.9991);平均回收率为99.40％(n=9),RSD为0.69％;测得姜黄素-磺丁基醚-β-环糊精的包合率为91.71％,RSD为0.38％.本方法操准确、简便、迅速,适用于姜黄素磺丁基-β-环糊精包合物中姜黄素含量的测定.     

紫外分光光度法测定葛根素-二甲基-β-环糊精的包合率

制备葛根素-二甲基-β-环糊精包合物并建立其包合率测定方法.采用紫外分光光度法测定葛根素-二甲基-β-环糊精包合物中葛根素的含量,由此计算包合率.结果表明葛根素在250nm处有最大吸收,浓度在15-65μg ·mL-1时与吸光度呈良好的线性关系,回归方程为:A=0.0129C+0.0313,r=0.9998(n=6);平均回收率为99.23％,RSD为0.68％;测得葛根素-二甲基-β-环糊精的包合率为96.58％,RSD为1.2％.该包合物制备和含量测定方法操作简便易行,准确可靠,得到葛根素-二甲基-β-环糊精包合物的包合率很高.     

电感耦合等离子体-质谱法测定食品中的总铬

食品样品使用微波消解处理后,选用质量数相近的钪(Sc)作为内标,使用电感耦合等离子体-质谱仪测定总铬含量.在0-150μg/L范围内,仪器响应值与总铬含量呈线性关系,线性方程为I=0.0429C,相关系数r=0.9998,检出限为0.022mg/kg,相对标准偏差(n=6)为4.58％,加标回收率在97.6％-104％之间.     

近红外光谱法测定有机混合物中的正己烷、环己烷、甲苯的含量

用近红外光谱法对具有不同含量水平的环己烷、正己烷、甲苯、苯的四氯化碳混合溶液中的环己烷、正己烷、甲苯进行了定量分析。对于体积百分含量在1.4％～20％之间的环己烷,校正集真值与预测值相关系数r=0.9969,RSD=0.34％;对于体积百分含量在0.04％～0.96％的正己烷,校正集真值与预测值相关系数r=0.9999,RSD=0.83％;对于含量在26.0～259.8mg·L~(-1)的甲苯,校正集真值与预测值相关系数r=0.9921,RSD=4.63％。近红外光谱可以检测到26.0mg·L~(-1)的含量水平,其预测值为25.9mg·L~(-1),相对误差为0.38％。结果表明,用近红外光谱快速、准确、同时测定不同含量水平的组份可以获得较理想的结果。     

RP-HPLC测定阿仑膦酸钠及有关物质4-氨基丁酸

建立邻苯二甲醛-2-巯基乙醇柱前衍生化高效液相色谱法测定阿仑膦酸钠及其有关物质4-氨基丁酸含量方法.采用Hypersil BDS C18色谱柱,乙腈-10mmol/L磷酸盐缓冲液(pH6.8 0,含0.05％ EDTA-2Na)为流动相梯度洗脱,流速为1mL/min,柱温30℃,紫外检测波长333nm.阿仑膦酸钠在2-40μg/mL范围内线性关系良好,线性方程为:y=30.665x+2.5641(r=0.9995),平均加样回收率为100.5％ (RSD=0.41％,n=5);4-氨基丁酸在0.05-2.00μg/mL范围内线性关系良好,线性方程为:y=357.76x+13.874(r=0.9996).方法简单、准确、灵敏,适用于阿仑膦酸钠和特殊杂质4-氨基丁酸的同时测定.     

固绿FCF褪色分光光度法测定利福平

采用可见分光光度法研究了固绿FCF与利福平的显色反应.实验表明,在水溶液中,在pH6.6-7.5的条件下,固绿FCF与利福平在室温下即可形成稳定的络合物,最大褪色波长λmax=655nm,表观摩尔吸光系数（ε）为2.44×105L/（mol·cm）,线性范围是0-0.82mg/L,线性回归方程为A=0.00228-0.2997ρ,r=-0.9985,相对标准偏差为1.0％-1.2％（n=6）,方法简便、快速、准确、灵敏.     

薄层扫描法测定消渴丸中葛根素的含量

以氯仿-甲醇-乙酸乙酯-水（3∶3∶4∶1）为展开剂,在硅胶GF254薄层板分离葛根素,采用薄层扫描法,以254 nm为检测波长测定消渴丸中葛根素的含量.结果表明葛根素在2.0-10.0μg范围内呈良好的线性关系,y=1064x＋ 16290,r=0.9949,平均回收率为101.1％,RSD=1.7％（n=5）.该法简便、准确、重现性好,可作为消渴丸质量控制的方法.     

5-Br-PADAP分光光度法测定食品中的微量铅

在pH 10.0的硼砂-氢氧化钠缓冲溶液中,非离子表面活性剂Tween-80存在下,铅与5-Br-PADAP生成有色络合物,其最大吸收波长为558nm,表观摩尔吸收系数ε=4.22×104L·mol-1·cm-1,pb2+的质量浓度在0-3.00μg·mL-1范围内符合比耳定律,线性回归方程为:A=0.06565C-0.0013(r=0.9991),用于食品中微量铅的测定,回收率为94.0％-104.0％,相对标准偏差小于3％.     

Off-Resonance Nutation NQR Spectra

Various methods for measuring multivariate nutation NQR spectra under off-resonance conditions are considered. A method is proposed which is based on optimum filtration. An experimental Cl-35 3D nutation NQR spectrum of chloral hydrate is reported for the first time.     

Nuclear quadrupole resonance exchange spectroscopy with shaped radiofrequency pulses

Recent work on the nuclear quadrupole resonance (NQR) investigation of molecular dynamics in the solid state has relied on 2D methods. We report our studies of dynamic processes by 1D shaped pulse NQR spectroscopy. Significant advantages include considerably shorter experimental duration, clear definition of the exchange time window, and avoidance of off-resonance effects. The reorientation of the Cl₃C? group in polycrystalline chloral hydrate [Cl₃C–CH(OH)₂] is considered as a test case. This may be modelled as a three-site exchange process. An analysis of the generalised Bloch–McConnell equation is performed to formulate the kinetic matrix. The present approach involves simultaneous excitation of the sites that undergo chemical exchange by employing a suitably modulated shaped RF pulse, followed by a mixing time, and finally a suitable read pulse for signal detection. The experimental signal intensities are plotted against the mixing time to extract the kinetic parameters, i.e. the exchange rate and the spin-lattice relaxation rate. Variable temperature measurements are carried out to determine the activation parameters. Short experiment times are possible in our 1D mode, enabling a large number of runs to be readily performed as a function of mixing time and temperature. The kinetic and activation parameters obtained in the case of chloral hydrate are in good agreement with recent literature values.     

纳米流体中气体水合物生成条件

为了研究纳米粒子对制冷剂水合物热力学生成条件的影响,建立了新型纳米流体中制冷剂水合物相平衡热力学模型,理论研究了HFC134a(R134a)气体水合物的热力学生成条件,并用实验验证了模拟结果.结果表明:新型纳米流体中制冷剂水合物热力学相平衡模型能够较好地反映纳米流体中制冷剂气体水合物相平衡特征,相同温度下相平衡最大相对误差为7.3%,平均相对误差为5.3%.     

Hydrodynamically induced crystallization of polymers from solution. VI. Amylose

A study has been made of the crystallization of amylose from stirred solutions. It was found that a highly turbulent flow can induce fibrillar crystallization in a 5% solution of amylose in 1 N KOH and in 35% chloral hydrate. Furthermore it was observed that these fibrillar crystals were insoluble in the original solution after crystallization.

Electron microscopic investigations revealed the presence of long fibrils, sometimes aggregated to larger units. Some fibers displayed transverse striations resembling the well-known shish-kebab structures. Treatment of the fibrillar crystals with iodine yielded the well-known blue coloring characteristic for amylose. However, in the electron microscope it was seen that only discrete portions of the fibers were stained.

Stirring of aqueous n-butanol solutions of amylose resulted in the formation of small rodlike fibrils in addition to lath-shaped single crystals to which a large number of tentacles were attached.

Rectangular-shaped crystals, grown in quiescent solutions, were deformed in a narrow gap couette instrument into long irregular fibers.     

Determination of Reorientation Angles from Two-Dimensional Exchange Spectra of Powders in Radiospectroscopy

A method for transforming a 2D exchange spectrum into an orientation representation is proposed which is based on finding the reorientation probability as a function of angles. A procedure of evaluation and analysis of two-dimensional magnetic spectra of powders is described and a method for finding the asymmetry parameter from 2D exchange spectra is proposed. The capabilities of the method are illustrated for a model ³⁵Cl 2D nutation exchange NQR spectrum of chloral hydrate CCl₃CH(OH)₂ and an experimental ¹³C 2D exchange NMR spectrum of dimethylsulphone CH₃–SO₂–CH₃. The asymmetry parameter of the chemical shift tensor for this compound is determined.     

瓦斯浓度影响下水合物晶体结构Raman光谱特征

在初始温压2 ℃,5 MPa条件下开展了三种瓦斯混合气(CH₄—C₂H₆—N₂,G1=54∶36∶10,G2=67.5∶22.5∶10,G3=81∶9∶10)水合实验,利用可见显微拉曼光谱仪获取水合产物拉曼光谱,通过水合物相中C₂H₆ C—C键伸缩振动特征峰拉曼位移判断水合物晶体结构,利用谱图特征峰分峰拟合方法计算出瓦斯水合物孔穴占有率、水合指数等。研究发现：气样G1和G2水合产物为I型水合物、G3为Ⅱ型,气样中C₂H₆浓度改变导致水合物晶体结构转变;Ⅰ型结构水合物相中CH₄和C₂H₆含量受气样浓度影响较小,G1和G2体系中CH₄含量分别为34.4%和35.7%、C₂H₆含量分别为64.6%和63.9%,而G3体系中CH₄和C₂H₆含量分别为73.5%和22.8%,晶体结构对水合物相客体分子含量控制作用明显;G1~G3体系水合物相大孔穴的CH₄—C₂H₆占有率分别为98%,98%和92%,小孔穴的CH₄占有率分别为80%,60%和84%,N₂由于分压较低且吸附能力较弱其小孔穴占有率不高于5%。     

MRI measurements of CO2 hydrate dissociation rate in a porous medium

After obtaining experimental data of CO₂ hydrate formation and dissociation in a porous medium using magnetic resonance imaging (MRI), the purpose of this study was to analyze the different dissociation rate of CO₂ hydrate using two heating rates. Images were obtained by using a fast spin-echo sequence, and the field of view was set to 40×40×40 mm. The vessel pressure was monitored during hydrate formation and dissociation, which was used to compare with MRI mean intensity. The result indicated that the MRI could visualize hydrate formation and dissociation, and the MRI mean intensity of water was in good agreement with the vessel pressure changes. The hydrate formation and dissociation rates were also quantified using the MRI mean intensity of water. The experimental results showed that the higher heating rate caused the rapid hydrate dissociation.     

ICP-AES法同时测定锑酸钠中的Fe、Cu、Cr和V

本文采用基体分离法，将锑酸钠经氢溴酸处理，加热挥发除锑，在5％盐酸介质中用ICP－AES同时测定锑酸钠中杂质元素Fe、Cu、Cr和V，并运用干扰系数法扣除元素间光谱干扰引起的分析偏差，回收率在93％－101％之间，结果较为满意。该方法操作简便、快速，适用于锑酸钠的日常进出口检验分析。     

CO2水合物在电解质溶液中的相平衡预测

关于二氧化碳水合物基础物性的研究,对二氧化碳置换开采天然气水合物和工业废气二氧化碳的深海埋藏具有重要意义。本文在Van der Waals-Platteeuw理论和Pizter的电解质模型的基础上,考虑了电解质和温度对二氧化碳在水中溶解度的影响,从理论上对水合物相平衡模型进行了修正,提高了预测的精度。本文预测了二氧化碳水合物在NaCl、KCl、CaCl₂、MgCl₂的一元及二元溶液体系中的相平衡条件,预测的最大压力误差7.92%,平均压力误差在1%～3%之间。结果表明,本文的理论预测结果和实验数据吻合较好。     

用分子动力学模拟甲烷水合物热激法结合化学试剂法分解

用分子动力学模拟方法研究甲烷水合物的热激法，化学试剂法，以及热激法结合化学试剂法分解，系统研究温度为277K和340K时添加液态水(WTR)和30wt％乙二醇(EG)溶液对水合物分解的影响.模拟显示WTR与水合物表面水分子形成氢键，破坏水合物原有的氢键平衡，造成笼状结构坍塌，水合物分解.EG分子中的羟基与水合物表面水分子形成氢键，从而破坏原有的稳定结构，造成水合物笼状结构被破坏，达到促进水合物分解，释放甲烷气体的效果.比较温度为277K和340K时添加WTR和30wt％EG溶液对水合物分解效果得出EG(340K)> WTR(340K)>EG(277K)>WTR(277K)，热激法结合化学试剂法能更好促进水合物分解.