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171.
用葡聚糖凝胶层析分离制备牛血清蛋白(BSA)-茜素红S(ARS)配合物。在420和530 nm处用紫外可见吸收光谱法同时测定含有BSA-ARS配合物和茜素红S的联立方程为:A420=4.89×103cARS 3.06×104cBSA-ARS,A530=4.60×102cARS 2.29×104cBSA-ARS;正交试验选择了合适的分离条件:柱直径1.0 cm,柱长30.0 cm,凝胶用量1.3 g,最佳进样浓度为ARS:5×10-3mol/L、BSA:1.49×10-4mol/L,进样体积1.5 mL,洗脱流速0.33 mL/min,分离度为1.25;测定了纯BSA-ARS配合物紫外吸收光谱,最大吸收峰在530 nm。 相似文献
172.
采用关键功能单体N,N'-二甲基间苯二胺(DMMPD)和多元酰氯5-氯甲酰氧基-异肽酰氯(CFIC)聚合制备了一种耐氧化的聚酰亚胺-氨酯(DMMPD-CFIC)反渗透复合膜材料. 研究了水相溶剂、 多元胺浓度和组成及两相接触时间等因素对DMMPD聚合成膜的影响. 结果表明, 虽然DMMPD-CFIC膜的脱盐率不够理想, 但将4-甲基间苯二胺(MMPD)与DMMPD以2∶1(质量比)组合后制得的MMPD/DMMPD-CFIC膜的脱盐率得到显著提高, 并且对膜的耐氯性能影响不大. 采用傅里叶衰减全反射红外光谱(FTIR)和X射线光电子能谱(XPS)分析了2种膜的活性层的结构, 并利用扫描电镜(SEM)和原子力显微镜(AFM)对膜的表面形态进行了表征. 相似文献
173.
174.
提出了纳米二氧化铈吸附富集痕量铬,2mol.L-1氢氧化钠溶液作洗脱剂洗脱,用二苯卡巴肼分光光度法测定环境水样中铬(Ⅵ)含量的方法。在pH 4.0的介质中、吸附时间为40min、吸附剂用量为20mg时,纳米二氧化铈对铬(Ⅵ)的吸附容量为696μg.g-1。铬(Ⅵ)与二苯卡巴肼络合物的最大吸收波长为540nm,其质量浓度在0.012~1.2mg.L-1之间呈线性,检出限(3σ)为0.01mg.L-1。方法用于环境水样中铬的测定,加标回收率为99.4%。 相似文献
175.
杜作栋等先后合成了四苯基苯基有机硅化合物和五苯基苯基有机硅化合物,并用溶剂沉淀法和重结晶法纯化产物后进行结构分析,在此基础上陈剑华等又合成了双多苯基苯基有机硅化合物,此类化合物具有更好的耐高温性能,可制成耐高温树脂、耐高温橡胶、耐高温粘合剂和耐高温涂料。 相似文献
176.
On-line sample-pre-treatment schemes for trace-level determinations of metals by coupling flow injection or sequential injection with ICP-MS 总被引:1,自引:0,他引:1
Within the last decade, the first generation of flow injection (FI) has been supplemented by sequential injection (SI), also termed the second generation, and, recently, by the third generation, i.e., SI-Lab-on-Valve (SI-LOV). As apparent from the literature, FI and/or SI have become dominant as substitutes for labor-intensive, manual, sample-pre-treatment and/or solution-handling procedures prior to analyte detection by inductively coupled plasma mass spectrometry (ICP-MS). The present review presents and discusses the progress of the state of the art in implementing miniaturized FI/SI systems for on-line matrix separation and pre-concentration of trace levels of metals with detection by ICP-MS. It highlights some of the frequently applied on-line, sample-pre-treatment schemes, including solid phase extraction (SPE), on-wall molecular sorption and precipitate/(co)-precipitate retention using a polytetrafluoroethylene (PTFE) knotted reactor (KR), solvent extraction-back extraction and hydride/vapor generation. It also addresses a novel, robust approach, whereby the protocol of SI-LOV-bead injection (BI) on-line separation and pre-concentration of ultra-trace levels of metals by a renewable microcolumn is interfaced to ICP-MS, as conducted in the present authors' group. It discusses the future outlook in this field. 相似文献
177.
大米品质的评价及其主要影响因素 总被引:3,自引:0,他引:3
概述了有关大米的成分,并初步分析了影响大米的品质的主要因素。其中包括大米的化学成分、物理特性以及一些环境因素,同时还简单说明了一些有关功能性大米的发展近况。 相似文献
178.
179.
Unursaikhan Surenjav Li-na Zhang Xiao-juan Xu Mei Zhang Peter Chi Keung Cheung Fan-bo Zeng 《高分子科学》2005,23(3)
Lentinan samples, (1→3)-β-D-glucans containing 4.6-15.2 wt% proteins, coded as L-I1, L-I2, L-I3 and L-I4 (L-I)were isolated from four kinds of Lentinus edodes. These glucans were treated with acetone to remove the protein in order to obtain free protein glucans coded as LNP-I1, LNP-I2, LNP-I3 and LNP-I4 (LNP-I). The free-protein polysaccharides were sulfated to give derivatives (S-LNP-I) with degree of substitution (DS) from 0.4-0.8. The structural features and weight- average molecular weight (Mw) of the samples were investigated by using infrared spectroscopy, elemental analysis,13C-NMR, size exclusion chromatography combined with laser light scattering (SEC-LLS) and viscometry. The effects of structure and conformation of the polysaccharides on antitumor activities were assayed in vivo (Sarcoma 180 solid tumors)and in vitro (Sarcoma 180, HL-60, MCF-7 and Vero tumors). The results indicated that the predominant species of the samples L-I and LNP-I in 0.2 mol/L NaCl aqueous solution existed as triple-helical chains with high rigidity and in dimethyl sulfoxide (DMSO) as single-flexible chains. Interestingly, the antitumor activities of LNP-I are lower than those of the native glucans (L-I), whereas their sulfated derivatives have higher inhibition ratio against Sarcoma 180 than LNP-I. The results reveal that the binding of protein, sulfated modification and the triple helix conformation are important factors in the enhancement of the antitumor activities of polysaccharides on the whole. 相似文献
180.
Determination of terbinafine in pharmaceuticals and dialyzates by capillary electrophoresis 总被引:1,自引:0,他引:1
A capillary electrophoresis method has been developed for the separation and determination of terbinafine (TER) in various pharmaceutically relevant matrices. Capillary zone electrophoresis (CZE) separation and UV absorbance photometric detection were carried out in a 160 mm capillary tube with a 300 μm i.d., hydrodynamically (membrane) closed. The influences of pH, carrier cation and counterion on migration parameters of TER were studied and the following conditions were selected: a 20 mmol l−1 glycine running buffer adjusted to pH 2.7 with acetic acid, 0.2% (w/v) methylhydroxyethylcellulose (m-HEC) as an electro-osmotic flow (EOF) suppressor, a 250 μA driving current, and 20 °C. The optimized separation conditions were convenient for the determination of TER in commercial tablets and spray and in dialyzates. Here, the dialysis was used to investigate in vitro permeation of TER through the skin from the gel. The samples of dialyzates were examined with and without simple extraction procedure and the results were compared. A permeation profile of the drug present in the gel of given composition was obtained analyzing pretreated samples. The proposed electrophoretic method was successfully validated. It was suitable for the simple, sensitive, rapid and highly reproducible assay of TER. CZE analysis was completed within 5.5 min. The detection limit of TER was 1.73 μmol l−1 at a 224 nm detection wavelength. The intra- and inter-laboratory precisions over the concentration range 6.0-60.0 μmol l−1 were between 0.32-0.69% and 1.04-1.44% including R.S.D. of migration times and peak areas, respectively. The mean absolute recoveries of drugs from samples were found to be 98.34 (tablets) and 99.47% (spray). It is suggested that there are potentialities to determine TER present in unpretreated complex samples, as CZE in a hydrodynamically closed separation system may be easily on-line combinable with purification and preconcentration CE modes (e.g., isotachophoresis, ITP). 相似文献