大蒜素提取检测及对肝癌细胞的灭活效果研究

采用溶剂提取法提取大蒜中的活性成分,探讨了不同酶解温度和大蒜捣碎粒径程度对大蒜素提取率的影响.通过正交试验,研究了硫酸钡吸光比浊法测定大蒜中大蒜素含量的最佳实验条件.在最佳实验条件下,体系的吸光度y与硫酸根离子浓度x呈线性关系:y=0.237x+0.002(r=0.9985).用MTT法对大蒜素提取浓缩液进行细胞活性检...     

仁东大蒜蛋白质的测定

采用碱提酸沉法提取分离大蒜蛋白,最佳提取条件为浸提碱液pH=7.2,浸提最佳时间为30min,沉淀的最佳pH=4.2.采用考马斯亮蓝G-250法测定大蒜中蛋白质的含量,结果表明蛋白质-色素结合物在590nm波长下的吸光度与蛋白质含量呈正比,线性范围为1.67-16.67μg/mL.标准溶液和试样的RSD分别为0.35％...     

ICP-AES间接测定膨化食品中的硫酸根和磷酸根

采用高压密封硝化罐法处理样品,以ICP-AES测定膨化食品中S、P的含量,从而间接测定硫酸根和磷酸根的含量.此方法简单、快速、灵敏度高、准确性好,且可多元素同时测定,另外环境污染小.该方法回收率在97.4%-104.7%之间,相对标准偏差均小于3.0%.     

原子吸收光谱法测定新疆不同居群大蒜中微量元素的含量

采用湿法消解处理大蒜样品,用原子吸收光谱法对新疆不同居群大蒜中Ca,Fe,Zn,Mg,Cu,Mn,Cr,Pb和Cd共九种微量元素的含量进行了测定,并进行了加标州收率实验.结果表明:不同居群大蒜中上述微量元素标准曲线的相关系数在0.994 4～0.999 8之间,呈现良好的线性关系;样晶测定结果的相对标准偏差(RSD)均不超过5.15%,各元素的加标回收率在99.4%～101.7%之间,测定结果准确可靠;新疆地产大蒜中对人体有益的微量元素含量较为丰富,不同样品中微量元素含量的差异一定程度上反映了南北疆之间地形地貌、气候、土壤、水文等环境要素的差异.     

硫酸钡分光光度比浊法间接测定有机催化剂2—乙基蒽醌中的硫

本文研究了用浓硝酸将２－乙基蒽醌中的硫定量转化成硫酸根，然后用硫酸钡分光光度比浊法间接测定其在充含量的方法，建立的方法简单，快速，实用。试样分析结果表明准确度及精度均符合要求。     

微波消解-ICP-OES,AAS和AFS测定大蒜不同部位20种元素含量

将大蒜植株分为根、茎(下)、茎(中)、茎(上)、嫩叶和老叶6个不同部位,采用微波消解方法对各个部位进行了预处理,并用电感耦合等离子体发射光谱法(ICP-OES)、原子吸收光谱法(AAS)和原子荧光光谱法(AFS)测定了其中Al,As,B,Ca,Cd,Cr,Cu,Fe,Hg,K,Mg,Mn,Na,Ni,P,Pb,S,Se,Sr和Zn共20种元素的含量,另外,还测定了从同一处土壤中采收的大蒜头中相应元素的含量.研究结果表明:大蒜植株嫩叶和大蒜头中Cu,Fe,Mn,S,Se,Zn等元素含量较高而As,Cd,Hg,Pb等元素含量较低,是提取大蒜生物活性物质的绝好材料;一些元素在大蒜植株不同部位的含量分布模式能高度反映植物生理特性或环境污染状况.     

硫酸钡分光光度比浊法间接测定有机催化剂2－乙基蒽醌中的硫

本文研究了用浓硝酸将２－乙基蒽醌中的硫定量转化成硫酸根，然后用硫酸钡分光光度比浊法间接测定其硫含量的方法。建立的方法简单、快速、实用。试样分析结果表明准确度及精密度均符合要求。     

乘因子法测定撒痛风注射液中三组分的含量

介绍了乘因子法的原理和计算步骤并用于处理多波长吸光度数据 ,同时测定撒痛风注射液中三组分的含量 ,10份撒痛风注射液模拟样中水杨酸钠、安替比林、咖啡因测定所得的置信区间分别为 (99.93±0 .16 ) %、(99.85± 0 17) %、(10 0 .19± 0 .2 8) % (置信度 95 % )。对两个批号的实际样品进行了测定 ,所得结果与标准法无显著差异     

褐藻硫酸根含量的离子色谱法分析

建立了碱熔-离子色谱测定褐藻中硫酸根含量的方法。样品采用NaOH熔剂,置于马弗炉500℃碱熔45min,经溶解,离心分离,阳离子交换树脂交换后,进样分析。色谱柱为IonPac AS11-HC,以KOH为淋洗液,设置梯度淋洗程序,淋洗液流速为1mL/min。在所选实验条件下,硫酸根在0.4—400mg/L浓度范围内具有良好的线性关系,相关系数r为0.9991,相对标准偏差为2.42%,检出限为0.6mg/kg,回收率在92.17%—109.0%之间。实验证明该方法操作简单,分析快速,结果准确,精密度高,适合于褐藻样品中硫酸根含量的测定。样品分析结果显示褐藻硫酸根含量丰富,尤其是羊栖菜,平均硫酸根含量达40.54g·kg^-1。     

烟草制品中硫含量测定的研究

本文研究了在聚乙烯醇－乙醇介质中,硫酸根离子能和钡离子形成稳定的胶体沉淀,硫含量在０－１．０ｍｇ／２５ｍＬ范围内符合比耳定律,本方法稳定性明显优于传统的硫酸钡比浊法,与重量法无显著差异,用于烟草制品中硫的沉淀,结果令人满意。     

发射光谱法同时测定10种稀土元素

研究了用碳粉、硫酸钾、硫酸钡、硫酸锶和三氧化二钪作缓冲剂同时测定样品中的La,Ce,Pr,Nd,Sm,Gd,Tb,Dy,Yb,Lu的发射光谱法。选择钪作内标线,不需分离、不需化学处理,直接压样于杯形的石墨电极中,具有简便、快速和准确。对测定条件、干扰因素进行了研究,从而建立测定10种稀土元素的新方法。10种稀土元素的检测限均在0.030%以下,其回收率在94%～105%范围内,当n=9时,它们的RSD均小于5%;用于样品的测定取得了满意的结果。     

煤中硫化物硫的间接火焰原子吸收法测定

研究了测铬的间接原子吸收法测硫的实验条件，结果表明，硫酸盐与铬酸钡的交换平衡时间也会影响分析结果。本文提出了间接原子吸收法测定煤中硫化物硫的方法。吸光度Ａ与ＣＳＯ４＾２－在０￣１６μｇ／ｍＬ范围内成线性关系。用于煤样品测定。平行测定结果的相对标准偏差为３￣５％，加标回收率为９５￣１０２％。     

Rheological Behavior and Interaction of Polycarbonate/Barium Sulfate Composites

The effect of microsized barium sulfate (BaSO ₄ ) on the rheological properties of Polycarbonate (PC) was investigated. The composite exhibits a reduced viscosity as compared to pure PC, indicating that use of barium sulfate is a new method to enhance the mobility of PC melts. Model calculation of this behavior was carried out according to a viscosity rheological equation. Values of model parameters were obtained and discussed. Other rheological properties were also determined, including frequency dependence of storage modulus and loss modulus. Analysis by Fourier Transform Infrared (FTIR) spectroscopy and X-ray Photoelectron Spectroscopy (XPS) shows that the barium sulfate fillers strongly interact with PC chains, with the type of interaction being determined.     

Barium sulfate suspension as a negative oral MRI contrast agent: in vitro and human optimization studies

In vitro proton spectroscopy with line-width measurements and MR imaging were performed on various concentrations of commercially available single contrast (SC), double contrast, oral and rectal barium sulfate suspensions, as well as potassium sulfate, barium chloride, barium hydroxide, and 97% pure barium sulfate suspensions. Approximately 500 ml of 20%, 40%, 60%, and 70% w/w suspensions of SC oral barium sulfate suspensions were administered to four normal volunteers, respectively, and MR images were obtained at both 1.5 T and 0.15 T. Subsequently, 500 ml of 60% w/w suspensions of SC oral barium sulfate suspensions were administered to five normal volunteers and imaged at 1.5 T. All of the inert suspensions produced line-width broadening but the SC oral barium sulfate suspension at 50% and 70% stayed in suspension even after hours of standing undisturbed. As much as 80% of the small bowel and the entire colon were well visualized using the combination of 60% or 70% w/w SC barium sulfate suspensions with SE 550/22 and FISP pulse sequences. The effect was less at 0.15 T and also with the SE 2000/45/90 pulse sequences. We conclude that barium sulfate suspensions are useful as oral MRI contrast agents.     

ICP-AES内标法测定硅铝钡合金中铝和钡

研究了以电感耦合等离子体发射光谱仪测定硅铝钡合金中铝和钡的方法。考查了方法的线性范围,检测限和RSD等指标,实验表明,方法简便,结果准确。     

Deconvolution of pure component FT‐Raman spectra from thermal emission of barium sulfate and graphite samples using the BTEM algorithm

Band‐target entropy minimization (BTEM) was applied for the extraction of pure component Raman spectra from samples exhibiting a significant thermal background due to sample emission. In this method, singular value decomposition was first used to calculate the right singular vectors of the spectroscopic data matrix. Then the non‐noise right singular vectors were examined for localized spectral features, which were subsequently used for spectral recovery. These local features were targeted with the BTEM algorithm to recover the pure component Raman spectra. Accordingly, the interfering thermal background was removed. This method of analysis is applied to graphite and barium sulfate Raman spectroscopic data. Copyright © 2006 John Wiley & Sons, Ltd.     

Understanding barium sulfate precipitation onto stainless steel

This paper investigates the influence of barium sulfate scaling and scaling inhibitors on the electrochemical behaviour of stainless steel. The results of a synchrotron radiation grazing incidence X-ray diffraction (SR-GIXRD) and electrochemical impedance spectroscopy (EIS) study on stainless steel shows that different scaling inhibitors interact uniquely with the substrate when barium sulfate is precipitated on the electrode surface. The main effect of the substrate in the presence of inhibitor is a tendency to form smaller barium sulfate particles. The SR-GIXRD patterns obtained in the presence of the two inhibitors were different to each other and to the control, with the carboxylate showing greater amounts of barite solids precipitated together with iron(III) and (II) sulfate, while the phosphonate showed low amounts of barite solid were precipitated. The presence of iron sulfates on the electrode surface as detected by SR-GIXRD, in the case of NTA, suggests that scaling inhibitors are not always benign, and can promote the dissolution of iron species from the substrate.     

Synthesis and surface properties of submicron barium sulfate particles

Barium sulfate particles were synthesized in the presence of EDTA at room temperature. X-ray diffractometry (XRD), Fourier transform infrared resonance (FTIR) and scanning electron microscopy (SEM) were used to characterize the structure and morphology of BaSO₄ particles. The effect of the preparation parameters on the particle size distribution and morphology was investigated. The conditional formation constants of Ba-EDTA at different pH values were calculated. The results show that the size and morphology of BaSO₄ particles can be effectively controlled by adding EDTA in the precipitation process. Among all the operation conditions, the pH value has significant effect on the particle size. The obtained barium sulfate particles are spherical and well dispersed at pH = 9-10. Zeta potentials of BaSO₄ were measured at different pH. The isoelectric point (IEP) of barium sulfate colloid appears at pH 6.92. The model of the solid-solution interface at a particle of BaSO₄ was presented. The FTIR result indicates that the surface of the prepared BaSO₄ absorbs the functional groups of EDTA, which lower the IEP of the barium sulfate particles.     

High density barium sulfate suspension for MRI: optimization of concentration for bowel opacification.

In this in vitro study of a potential oral MRI contrast agent, barium sulfate suspension (BSS), the object was to examine the effect of varying barium sulfate concentration on signal intensity while keeping suspension additives the same; and to optimize the concentration of a specific preparation of BSS. A phantom was used to test suspensions with concentrations of barium sulfate ranging from 90% to 220% w/v. T1-weighted, T2-weighted, and gradient echo sequences all showed a decrease in signal as concentration was increased to 170%. Between 170% and 220%, the signal intensity was constant on the T1-weighted and T2-weighted sequences. With the proton density and gradient echo sequences, there was a slower rate of decline in the signal intensity in the 170 to 220% range of BSS concentrations. We conclude that BSS with a concentration in the range of 170% to 220% w/v is optimum for the specific preparation used. We speculate that the behavior of the signal-to-noise ratio with changing concentration is explained by factors including proton density, T1 relaxation enhancement, diffusion effects, and magnetic field inhomogeneity, depending on the particular pulse sequence used.