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1.
毛细管电泳高频电导法测定虫草中的有效成份 总被引:1,自引:0,他引:1
建立了毛细管电泳高频电导法同时测定腺苷和虫草素的方法。实验对电泳介质的种类、浓度以及操作电压和进样时间等因素进行了优化,在4mmol/L乳酸+10%异丙醇+80μg/mL羟甲基纤维素钠(pH=4.0),分离电压20.OkV的条下测定了天然虫草和人工虫草菌丝制品中的腺苷和虫草素的含量,线性范围分别为2.0μg/mL~120μg/mL和3.0μg/mL~110μg/mL,检出限分别为0.5μg/mL和1.0μg/mL。 相似文献
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高效毛细管电泳电导法快速检测复方维生素B片中的VBl、VBl2、VB6和VC 总被引:1,自引:0,他引:1
采用高效毛细管电泳电导法同时分离、测定了复方维生素B片中的主要成分VB1,VB12,VB6和VC的含量。研究了运行缓冲溶液的酸度和浓度、电泳电压、进样时间等因素对电泳的影响。在优化的实验条件下:40mmol/L Tris-4mmol/L H3BO3(pH8.0)的缓冲溶液中加入0.30mmol/L CTAB(溴化十六烷基三甲基铵),分离电压为15kV,上述4组分在5min内得到良好的分离。维生素B1,B12,B6和VC的线性范围分别为5.5~1.0mg/mL;15~1.5mg/mL;1.0~0.40mg/mL和6.6~0.80mg/mL;检测限分别为0.80μg/mL,4.0μg/mL,0.50μg/mL,2.9μg/mL;5次测定峰高的相对标准偏差分别为2.2%,1.6%,3.9%,2.8%。5次测定的平均回收率分别为99%,94%,l00%,97%。 相似文献
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单扫描示波极谱法连测五味子、榛蘑中的铜和锌 总被引:1,自引:0,他引:1
研究了在HCl-KSCN底液中用单扫描示波极谱法连续测定五味子、榛蘑中铜和锌的方法。在此底液中,铜、锌分别在-0.42V(vs.SCE)、-1.03V(vs.SCE)处产生一敏锐的二阶导数波,检出限分别为0.005、0.01μg/mL,线性范围分别为0.01~8.00μg/mL,0.01~10.00μg/mL。应用本方法测定了五味子、榛蘑中的铜和锌,方法回收率为96.5%~101.8%。 相似文献
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提出了一种测定左旋氧氟沙星(LEV)的荧光光谱新方法。该法基于电子受体氯冉酸(CL)和2,3-二氰-5,6-二氯-1,4-对苯醌(DDQ)与电子给体左旋氧氟沙星之间的荷移反应,显示这两种受体能强烈增敏LEV的荧光强度。对影响反应的不同变量和参数进行了研究,建立了两种荧光光谱法测定LEV的新体系:(1)CL体系,线性范围为0.06~3.6μg/mL,检出限为0.02μg/mL;(2)DDQ体系,线性范围为0.12~2.2μg/mL,检出限为0.04μg/mL。所提方法已用于制剂中左旋氧氟沙星含量的测定,回收率分别为99.72%~99.36%和99.36%~98.86%。 相似文献
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双波长分光光度法测定阿丙沙星可溶性粉中阿莫西林、盐酸环丙沙星的含量 总被引:1,自引:0,他引:1
应用双波长分光光度法测定阿丙沙星可溶性粉中阿莫西林、盐酸环丙沙星的含量。以pH=5.0的磷酸盐缓冲液为溶剂,在波长229、248、315、400nm处进行测定,阿莫西林的浓度在5.130~25.650μg/mL、盐酸环丙沙星的浓度在4.888~24.440μg/mL范围内分别与其吸光度差值呈良好的线性关系。阿莫西林的回收率为99.30%~100.19%,测定结果的相对标准偏差为0.60%~1.00%(n=5),盐酸环丙沙星的回收率为99.30%~99.86%,测定结果的相对标准偏差为0.84%~1.02%(n=5)。 相似文献
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Osmotic coefficients measured by vapor pressure osmometry are reported for aqueous bile salt solutions at 25, 37, and 45°C. Solute activities decrease rapidly with increasing concentration due to premicellar association and micelle formation. In all cases, activities of the dihydroxy bile salts are lower than those of the trihydroxy bile salts. Osmotic coefficients and activity coefficients increase with increasing temperature. It is suggested that hydrophobic forces contribute substantially to the stability of primary bile salt aggregates and micelles. 相似文献
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胆酸盐在酸性介质中自聚集作用的共振瑞利散射光谱及其分析应用研究 总被引:3,自引:0,他引:3
研究了牛磺胆酸钠、甘牛胆酸钠、胆酸钠和脱氧胆酸钠等四种胆酸盐在酸性介质中的聚集作用对共振瑞利散射光谱的影响及其分析应用. 结果表明: 在一定浓度的HCl, H2SO4或HNO3溶液中, 四种胆酸盐均能自聚集形成粒径增大的聚集体. 该聚集体能导致溶液RRS显著增强, 并产生了新的RRS光谱. 不同胆酸盐在同种介质中的反应产物具有相似的光谱特征, 最大RRS波长分别位于349 (HNO3介质), 359 (H2SO4介质)和369 nm (HCl介质). 在一定范围内, 胆酸盐的浓度与散射强度(ΔIRRS)成正比. 对于不同的体系其检出限在12.0~21.8 ng/mL之间. 方法灵敏度高, 选择性较好, 而且十分简便快速. 可用于市售蛇胆川贝液和血清样品中胆酸盐的测定. 相似文献
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Facile Stabilization of the Sodium Metal Anode with Additives: Unexpected Key Role of Sodium Polysulfide and Adverse Effect of Sodium Nitrate 下载免费PDF全文
Dr. Huan Wang Chuanlong Wang Edward Matios Prof. Weiyang Li 《Angewandte Chemie (International ed. in English)》2018,57(26):7734-7737
Sodium metal is an attractive anode for next‐generation energy storage systems owing to its high specific capacity, low cost, and high abundance. Nevertheless, uncontrolled Na dendrite growth caused by the formation of unstable solid electrolyte interphase (SEI) leads to poor cycling performance and severe safety concerns. Sodium polysulfide (Na2S6) alone is revealed to serve as a positive additive or pre‐passivation agent in ether electrolyte to improve the long‐term stability and reversibility of the Na anode, while Na2S6‐NaNO3 as co‐additive has an adverse effect, contrary to the prior findings in the lithium anode system. A superior cycling behavior of Na anode is first demonstrated at a current density up to 10 mA cm?2 and a capacity up to 5 mAh cm?2 over 100 cycles. As a proof of concept, a high‐capacity Na‐S battery was prepared by pre‐passivating the Na anode with Na2S6. This study gives insights into understanding the differences between Li and Na systems. 相似文献
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T. Ito Y. Yoshioka T. Sonoda Y. Yoshihashi E. Yonemochi K. Terada 《Journal of Thermal Analysis and Calorimetry》2006,85(3):731-739
Glass
ampoule breakage during the freeze-drying process was prevented by the addition
of sodium chloride to the formulation of lyophilization products of sodium
thiopental. In order to clarify the ampoule breakage prevention mechanism,
the physicochemical behavior of the freeze-drying process was monitored by
simultaneous XRD-DSC measurements and thermal mechanical analysis (TMA). During
the freezing process of formulated solution, the smaller heat of fusion of
crystallized ice with the addition of sodium chloride was observed in comparison
to that without sodium chloride. Although a greater amorphous portion remained,
a higher crystal habit of hexagonal ice was reproducibly observed in the XRD
patterns with the addition of sodium chloride during the freezing process.
In the measurement of TMA, the scattering of the thermal expansion rate of
formulated solution was significantly reduced by the addition of sodium chloride.
These observations indicated that the addition of sodium chloride minimized
the scattering of the thermal expansion rate and might be a cause for the
inhibition of glass ampoule breakage during the freeze-drying process. 相似文献
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30%亚硫酸氢钠溶液样品中Cl~-和SO_4~(2-)的同时测定 总被引:1,自引:0,他引:1
建立了采用离子色谱测定 30%亚硫酸氢钠溶液样品中的氯化钠和硫酸钠含量的新方法。采用IonPacAS14分析柱,选择三乙醇胺为亚硫酸氢钠的稳定剂,以丙酮为有机改进剂,淋洗液组成为 1 5mol/LNa2CO3 3 5mol/LNaHCO3 10% (体积分数) (CH3 )2CO,流速为 1 0mL/min,抑制电导检测。实验结果表明,氯离子、硫酸根离子分别在 0.05~1.5mg/L,0.20~15mg/L时,其峰面积与质量浓度呈线性关系,相关系数均大于 0.999,检出限分别为0 01mg/L和 0 03mg/L。该法用于实际样品分析,操作便捷,结果可靠。 相似文献
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Single crystals of a new form of sodium octoborate, β-Na2B8O13, were obtained fortuitously from a complex Na2O-B2O3-P2O5 mixture, and studied. The compound is monoclinic, space group P21/c; the unit cell parameters are a=11.731(4) Å, b=7.880(3) Å, c=10.410(4) Å, β=99.883(3)°; Z=4. The crystal structure was solved from 1653 reflections until R1=0.0444; it consists of two infinite, independent, and interleaved boron-oxygen networks containing a complex borate anion (B8O13)2− formed by six BO3 triangles (Δ) and two BO4 tetrahedra (T), which can be viewed as a B5O10 group linked to a B3O7 group; this leads to a Fundamental Building Block (FBB) with the shorthand notation: 8: ∞3 [(5:4Δ+T)+(3:2Δ+T)]. This FBB is identical to that described in other octoborates such as α-Na2B8O13 and Ag2B8O13. However, some subtle differences exist in the interlinking of the octoborate anions found in these three compounds, which explains their different structure and unit cell parameters. 相似文献
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This study investigates the effect of additives in the nonsolvent water in terms of cloud point during the phase inversion of Polysulfone (PS) in dimethyl formamide (DMF). The exponential pattern is observed with PS concentration (0.2 to 0.6% (w/w)). It needs a low amount of water to get the cloud point at low temperature. The cloud point varied with the nature of water matrix and depended on the amount of salt, as well as the PS amount. The presence of salts (sodium chloride and sodium sulfate) lowers the cloud point of the solution. The network distribution of the particles at the cloud point is disturbed in the presence of salt. The requirement is more for Sodium lauryl sulfate (SLS) added water to reach the cloud point in the low range of PS solution up to 0.3% PS (w/w). The morphological and distribution pattern of PS particles are very different compared to PS particles produced from pure water. XRD study of PS particles produced from the mixed water system reflects relatively more amorphous character with respect to PS particles from pure water. The presence of both surfactant and salts in water systems also influences the cloud point in synergistic manner. 相似文献
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建立了毛细管区带电泳法同时测定注射用头孢哌酮钠他唑巴坦钠中目标成分含量的方法。采用石英毛细管(75 cm×75 μm i.d.,有效长度63 cm),以40 mmol/L硼砂溶液为背景电解质(BGE),以氢氯噻嗪为内标,分离电压12.0 kV,检测波长220 nm,重力进样10 s(高度10 cm)。实验结果表明,头孢哌酮钠与他唑巴坦钠分别在0.25~3.96 g/L和0.062~0.99 g/L范围内呈良好的线性关系,相关系数(r)分别为0.9995和0.9996。精密度和重复性均良好,相对峰面积的相对标准偏差(RSD)均小于3%,制剂在208 min内稳定,回收试验结果符合方法学要求。该方法简单、准确、耗费少、污染小,可用于注射用粉针剂头孢哌酮钠他唑巴坦钠中头孢哌酮钠和他唑巴坦钠的定量分析。 相似文献
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马兵兵 《中国无机分析化学》2015,5(2):53-55
采用自动电位滴定法,用硝酸银标准溶液作为滴定剂,测定工业碳酸钠中氯化钠含量。方法检出限为0.13mg/L,不同含量氯化钠样品加标回收率为99.7%~100.3%,相对标准偏差(n=5)为0.17%~2.0%,方法简单、快速,精密度和准确度高,适合大批量快速分析样品。 相似文献
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本文在自行研制的高效毛细管电泳仪上建立了复合硝基酚钠盐的胶束电动力学毛细管色谱分析方法。用50mmol/L十二烷基硫酸钠、pH=9.0的硼酸盐缓冲溶液,在20kV电压下分离了5-硝基愈创木酚钠、对硝基酚钠、邻硝基酚钠,此法用于Atonik型植物生长调节剂的定量分析,相对偏差小于2%,回收率在101% ̄105%之间。 相似文献