磺胺甲恶唑的二阶导数差示脉冲极谱法测定

建立了磺胺甲恶唑的二阶导数差示脉冲极谱定量分析方法,磺胺甲恶唑在１０％ＨＣｌ－（硼酸－氯化钾缓冲溶液）－水（５：５：９０）的底液中,于－１．４５Ｖ（ｖｓ．Ａｇ／ＡｇＣｌ）处出现一良好的二阶导数差示脉冲极谱峰,磺胺甲恶唑浓度与其峰高在０．０８～０．８０ｍｍｏｌ／Ｌ范围内呈线性关系（ｐ〈０．０１）,检测限为８．６ｎｍｏｌ／Ｌ。本法简便、快速、灵敏、结果准确。     

一阶导数差示脉冲极谱法用于扑热息痛的定量分析

一阶导数差示脉冲极谱法用于扑热息痛及其制剂的定量分析，在乙醇－水－２．０×１０＾－＾３ｍｏｌ／ＬＨ２ＳＯ４（１２．５：１１．５：１）的溶液中，于０．２４Ｖ（ｕｓＡｇ／ＡｇＣｌ）处出现良好的一阶导数差示脉冲极谱峰，在３．３×１０＾－＾４～３．３×１０＾－＾３ｍｏｌ／Ｌ范围内，浓度与其一阶导数差示脉冲极谱峰值呈线性关系，检测限为７．８×１０＾－＾８ｍｏｌ／Ｌ。方法简便，快速，灵敏，结果准确。     

牡丹皮中丹皮酚的二阶导数差示脉冲极谱法定量研究

建立了中草药牡丹皮中丹皮酚的二阶导数差示脉冲极谱定量分析方法。丹皮酚在１ｍｍｏｌ／Ｌ－１ｍｍｏｌ／Ｌ氯化钾－水（１：１：２３）的溶液中,于－１．６．３０Ｖ（ｓ ａｇ／ＡｇＣｌ）处出现一良好的二阶导数差示脉冲极谱峰,其峰幅值与丹皮酚在０．１～０．６ｍｍｏｌ／Ｌ范围内呈非常显著的线性关系（Ｐ〈０．０１）,检测限为９．２ｍｍｏｌ／Ｌ。本法简便、快速、灵敏,且结果准确。     

一阶导数差示脉冲极谱法用于甲硝唑的定量研究

本实验运用一阶导数差示脉冲极谱法对甲硝唑及其制剂进行了定量研究。在０．００１ｍｏｌ／Ｌ氯化钾－０．００１ｍｏｌ／Ｌ盐酸－水（１＋０．２＋４８）的底液中，甲硝唑于－０．８００Ｖ（ｖｓ Ａｇ／ＡｇＣｌ）处出现一良好的一阶导数差示脉冲极谱峰，在５０～３００μｇ／ｍＬ范围内，药物浓度与其导数峰幅值呈线关系，检测限为８．０×１０＾－８ｍｏｌ／Ｌ。本法操作简便，快速，灵敏，结果准确。     

二阶导数差示脉冲极谱法用于醋酸氟氢可的松的定量研究

用二阶导数差示脉冲极谱法对醋酸氟氢可的松进行了定量分析。在０．００１ｍｏｌ／Ｌ硫酸＋乙醇＋水（１＋２５＋２４）的底液中，醋酸氟氢可的松于－０．３４０Ｖ（ｖｓＡｇ／ＡｇＣｌ）处出现一良好的二阶导数差示脉冲极谱峰，在５～１４０μｇ／ｍＬ范围内，醋酸氟氢可的松的浓度与其二阶导数差示脉冲极谱峰幅值呈线性关系，检测限为０．４ｎｇ／ｍＬ。本法操作简便、快速、灵敏、结果准确。     

二阶导数差示脉冲极法用于醋酸氟氢可的松的定量研究

用二阶导数差示脉冲极谱法对醛酸氟氢松进行了定量分析。在０．００１ｍｏｌ／Ｌ硫酸＋乙醇＋水（１＋２５＋２４）的底液中，醋酸氟氢可的松于－０．３４０Ｖ处出现一良好的二阶导数差示脉冲极谱，在５－１４０μｇ／ｍＬ范围内，醋酸氟氢可的松的浓度与其二阶导数差示脉冲极谱峰幅值呈线性关系，检测限为０．４ｎｇ／ｍＬ。本法操作简单、快速、灵敏、结果准确。     

维生素C及其制剂的一阶导数差示脉冲极谱法测定

本文建立了维生素Ｃ及其制剂的一阶导数差示脉冲极谱定量分析方法，在水溶液中，维生素Ｃ于－１．１０Ｖ（ｖｓＡｇ／ＡｇＣｌ）处出现一良好的一阶导数差示脉冲极谱峰，在１～１７５μｇ／ｍＬ范围内，维生素Ｃ浓度与其一阶导数差示脉冲极谱峰幅值呈非常显著的线性关系（Ｐ〈０．０１），方法简便，快速，灵敏，结果准确。     

一阶导数差示脉冲极谱法测定氢氯噻嗪的研究

本研究了一阶导数差示脉冲极谱法用于氢氯噻嗪及其制剂的定量分析。在０．００２ｍｏｌ／Ｌ盐酸－０．００２ｍｏｌ／Ｌ氯化钾底液中，于０．０５０Ｖ（ｖｓ．Ａｇ／ＡｇＣｌ）处出现良好的一阶导数极谱峰，氢氯噻嗪浓度在０～６．０×１０＾－４ｍｏｌ／Ｌ范围内，与峰高呈线性关系，检测限为４．０×１０＾－９ｍｏｌ／Ｌ。方法操作简便、快速、灵敏、结果准确。     

抗癌药物博莱霉素伏安行为及其反应机理研究

博莱霉素（ＢＬＥＯ）Ａ５在０．０５ｍｏｌ／Ｌ Ｈ２ＳＯ４溶液中出现两个还原波，峰电位分别为ＥＰ１＝－０．８３Ｖ和ＥＰ２＝－１．０９Ｖ（ｖｓ．，Ａｇ／ＡｇＣｌ）。用线性扫描与循环伏安法、恒电位库仑法、脉冲极谱、交流极谱等手段研究体系的伏安行为及反应机理。实验表明，Ｐ１为ＢＬＥＯＡ５分子中嘧啶环第一步两电子还原的吸附波，Ｐ２为嘧啶环第二、三步还原和催化氢还原的具有吸附性的重叠波。     

二阶导数差示脉冲极谱法用于咖啡因测定的研究

本文用二阶导数差示脉冲极谱法对咖啡因及其制剂的测定进行了研究。先把咖啡因用０．０１ｍｏｌ／Ｌ／ＮａＯＨ溶解，并加热分解生成咖啡亭，生成物在０．００２ｍｏｌ／ＬＨＣＬ－０．００４ｍｏｌ／ＬＮａＣｌ底液中，于一１．０１０Ｖ（Ａｇ／ＡｇＣｌ）处出现一良好的极谱峰，峰高在０～３．３×１０－３ｍｏｌ／Ｌ范围内与咖啡因的浓度呈线性关系。方法简便、快速、灵敏、结果准确。     

溴取代紫外光度法同时测定痕量磺胺嘧啶和磺胺二甲嘧啶

提出了同时测定痕量磺胺嘧啶(SD)和磺胺二甲嘧啶(SM2)的溴取代紫外光度分析法, 实验结果表明: 在6×10-5 mol/L Br2, 2.5×10-3 mol/L KI溶液和体积分数40%乙醇溶液中, 测定SD和SM2的线性范围分别为: 0～2.25 mg/L, 和0～1.125 mg/L, 摩尔吸光系数(L·moL-1·cm-1)分别为: 在水中9.66×104和8.16×104, 在乙醇水溶液中1.25×105, 1.99×105. 用此法对猪肉中SD和SM2进行测定, 猪肉中SD和SM2的质量分数分别为7.53、7.35 mg/kg, 回收率在91.4%～104.4%, SD和SM2的相对标准偏差分别为0.5%、1.5%.     

Selectivity of two types of sulfadimidine-imprinted monolithic polymer-based fibers

Molecularly imprinted polymeric monolithic fiber is a new technique of solid-phase microextraction that focuses on selectivity. However, the inner mechanism of increasing the selectivity is not well understood. Here, a new approach to improve the selectivity is shown through controlling the surface of a molecular imprinted polymeric monolithic fiber. Sulfadimidine-imprinted polymeric monolithic fibers were fabricated using two kinds of molds, the polytetrafluoroethylene capillary and the silica capillary. A mixture of sulfadimidine, sulfamerazine, sulfadiazine, and sulfametoxypirydazine was used to test the selectivity of the fibers to sulfadimidine. This paper demonstrates that the extraction ratio for sulfadimidine in mixture is increased to more than 150% in sulfadimidine-imprinted polymeric monolithic fiber compared to nonimprinted polymeric monolithic fiber. The extraction ratio is increased to about 30% in sulfadimidine-imprinted polymeric monolithic fiber fabricated from silica capillary than in the counterpart from nonimprinted polymeric monolithic fiber. The sulfadimidine-imprinted polymeric monolithic fibers were also applied to extract standard mixtures spiked into Pearl River water and milk. The results indicated that polytetrafluoroethylene-sulfadimidine imprinted polymeric monolithic fiber showed highest selectivity to sulfadimidine in complex samples.     

毛细管电泳-电导法分离检测磺胺嘧啶、磺胺甲嘧啶和磺胺二甲嘧啶

磺胺嘧啶(SD)、磺胺甲嘧啶(SM)、磺胺二甲嘧啶(SM2)是常用的磺胺类药物[1],在结构上彼此只相差1个甲基(结构式见图1)。毛细管电泳(CE)由其高效、低耗、快速、环境友好等特点而成为药物分析中极具吸引力的分析方法[2-3]。近年来,文献报道采用CE方法分析磺胺药物均使用紫外检测[4     

Cu~(2+)络合萃取FAAS法间接测定磺胺二甲嘧啶钠

在pH为5.0~6.5的溶液中,磺胺二甲嘧啶盐与Cu2+结合形成2:1络合物,此络合物用氯仿萃取,火焰原子吸收光度法测定络合萃取后水相中剩余Cu2+的吸光度A。发现试剂空白溶液与试样溶液的萃余液之间Cu2+吸光度差ΔA随磺胺二甲嘧啶含量增大而线性增大。据此,我们建立了一种Cu2+络合萃取FAAS法间接测定磺胺二甲嘧啶新方法。优化条件下,方法线性范围为14.6~144mg/L,线性回归方程为ΔA=0.0025ρ-0.0046(r=0.9991)。检出限为5.6mg/L,方法回收率为99.3%~99.6%。     

Osmotic and activity coefficients of aqueous bile salt solutions at 25, 37, and 45°C

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.     

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

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(ΔI_RRS)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.     

Facile Stabilization of the Sodium Metal Anode with Additives: Unexpected Key Role of Sodium Polysulfide and Adverse Effect of Sodium Nitrate

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.     

30%亚硫酸氢钠溶液样品中Cl~-和SO_4~(2-)的同时测定

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。     

Mechanism of glass ampoule breakage prevention during the freeze-drying process of sodium thiopental lyophilization products on addition of sodium chloride

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.     

Studies on the Effects of Salt and Surfactant in Wet Phase Separation of Polysulfone

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.