在丙酮增敏作用下硝普钠分光光度法测定盐酸吗啉胍

摘要：建立了可见分光光度法测定盐酸吗啉胍的新方法。研究表明,当NaOH浓度为0.13mol/L,在丙酮存在下硝普钠与盐酸吗啉胍反应生成紫色N-亚硝基类化合物,其最大吸收波长为508nm,表观摩尔吸光系数2.5×10³ L/（mol•cm）。盐酸吗啉胍浓度在0.38×10^-6~3.0×10^-4 g/mL范围内与吸光度呈现良好线性关系,线性回归方程A = 0.02292 + 0.01213c (10^-6 g/mL),线性相关系数r=0.9998,检测限(3σ/k)为0.25×10^-6 g/mL,RSD = 0.21%。本方法可用于药物样品和血清中盐酸吗啉胍含量的测定。     

采用二维气相色谱及毛细管色谱柱分析汽油中苯和甲苯的含量

采用微板流路控制技术(Deans Switch)和常见的商品毛细管柱HP-5 (30 m×0.32 mm×0.25 μm)和Rtx-TCEP (30 m×0.25 mm×0.4 μm),建立了一种全新的分析车用汽油中苯和甲苯含量的二维气相色谱方法。用该方法分析汽油中0～5%的苯和0～20%的甲苯,两者校正曲线的线性关系良好,相关系数分别为0.9994和0.9999;标准样品5次重复测定的相对标准偏差均小于1.5%;车用汽油实际样品中苯和甲苯的加标回收率在96.8%～103.8%之间。车用汽油实际样品测定结果和SH/T 0713-2002标准方法测定结果一致。该方法是车用汽油中苯和甲苯含量测定的一种简便快捷、准确可靠的分析方法。     

液相色谱-电喷雾质谱法分析脂肪醇聚氧乙烯醚硫酸钠

采用电喷雾质谱(ESI/MS)技术建立了脂肪醇聚氧乙烯醚硫酸钠(AES)的烷基碳链分布、乙氧基分布及平均EO数、平均相对分子质量的测定方法;采用液相色谱-电喷雾质谱(LC-ESI/MS)测定了AES中的游离十二烷基硫酸钠(SDS)的含量。将本方法应用于实际样品的测定,并与核磁共振法测得的平均EO数进行比较,二者的测定结果相当吻合,从而验证了本法的可靠性。     

稳态荧光探针法研究二聚壬基酚聚氧乙烯醚硫酸钠的表面行为

介绍了以二聚壬基酚聚氧乙烯醚,氨基磺酸,氢氧化钠为原料,合成二聚壬基酚聚氧乙烯醚硫酸钠(GNPES),同样方法合成壬基酚聚氧乙烯醚硫酸钠(NPES),以芘为荧光探针,用稳态荧光探针法测定了合成的GNPES和NPES的临界胶束浓度。     

2-巯基乙磺酸铜配位聚合物的合成与晶体结构

以2-巯基乙磺酸钠为配体,2,2'-联吡啶,4,4'-联吡啶为辅助配体,与硝酸铜反应,得到一种一维链状配位聚合物 [CuL(4,4'-bipy)(2,2'-bipy)H2O]n (L=-O3S-CH2-CH2-S-S-CH2-CH2-SO-3),通过元素分析、红外光谱对其进行了表征,并用X射线衍射测定了其结构.结果表明:该配合物属于单斜晶系,P2(1)/c空间群,晶胞参数为:a=0.8385(2) nm,b=1.3764(3) nm,c=2.1719(5) nm,β = 93.391(3) °,V = 2.5023(10) nm3,Z = 4.     

溶剂热法合成六方氮化硼纳米晶的影响因素研究

以Li_3N和BBr3为原料,采用溶剂热法在220 ℃合成了h-BN纳米晶,研究了反应时间、表面活性剂和诱导晶粒对产物的影响.研究结果表明:反应产物主要为h-BN,同时含有少量c-BN,随着反应时间从12 h延长至36 h,晶粒尺寸从20 nm增大至80 nm;十二烷基苯磺酸钠的引入可以控制产物颗粒尺寸在10 nm左右,并且使球形度得到提高;以h-AlN为诱导晶粒时,产物中六方相含量增加,并且出现了h-BN纳米棒.     

光度法同时测定铂和钯

水溶性试剂N-间甲苯基-N’-(对氨基苯磺酸钠)硫脲(MMPT)在HAc-NaAc缓冲介质和CTMAB(溴化十六烷基三甲胺)存在下,与铂(Ⅳ)和钯(Ⅱ)反应形成绿色和褐色水溶性络合物,其最大吸收波长分别为754.4和304.6 nm。符合比尔定律的浓度范围分别为0～32 μg·(25 mL)-1, 0～25 μg·25(mL)-1,摩尔吸光系数为εPt_754.4=8.6×104 L·mol-1·cm-1和εPd304.6=7.4×104 L·mol-1·cm-1。在754.4和304.6 nm波长测定铂,钯混合液的吸光度,换算出铂、钯的含量。50种共存离子中, 仅有Cu2+和Co2+ 对钯的测定有干扰。该法选择性好,用于合成样品、矿石和催化剂样品中铂、钯含量的测定, 其相对标准偏差RSD小于2.0%;回收实验回收率是96%～104%。由于试剂铂、钯形成的络合物都易溶于水、不需予先分离同时测定,操作简便,快速,且环境友好。     

Selective Oxidation of Clopidogrel by Peroxymonosulfate (PMS) and Sodium Halide (NaX) System: An NMR Study

A selective transformation of clopidogrel hydrogen sulfate (CLP) by reactive halogen species (HOX) generated from peroxymonosulfate (PMS) and sodium halide (NaX) is described. Other sustainable oxidants as well as different solvents have also been investigated. As result of this study, for each sodium salt the reaction conditions were optimized, and four different degradation products were formed. Three products were halogenated at C-2 on the thiophene ring and have concomitant functional transformation, such as N-oxide in the piperidine group. A halogenated endo-iminium product was also observed. With this condition, a fast preparation of known endo-iminium clopidogrel impurity (new counterion) was reported as well. The progress of the reaction was monitored using nuclear magnetic resonance spectroscopy as an analytical tool and all the products were characterized by 1D-, 2D-NMR and HRMS.     

Diblock copolymer adsorption from the aqueous micellar phase to solid surfaces: real time monitoring by ATR spectroscopy in the mid-infrared

Attenuated Total Reflectance (ATR) in the mid-infrared is employed to monitor the adsorption of poly(tert-butyl styrene - b - styrene sulfonate), PtBS-PSS, copolymers with a small hydrophobic head as well as of an analogous poly(styrene sulfonate), PSS, homopolymer on germanium and Au-plated germanium surfaces from aqueous NaCl solutions. The surface density of the adsorbed polyelectrolyte is monitored via the growth of characteristic infrared absorptions of the sulfonated ring at 1036- and 1008 cm⁻¹ in the 2nd derivative mode. These probe bands do not exhibit shifts or changes in bandshape over very prolongued adsorption experiments. Pronounced differences in the kinetics of adsorption are observed between the PSS homopolymer and the PtBS-PSS copolymers in agreement to previous investigations by phase-modulated ellipsometry on similar systems. Adsorption of the diblocks above the critical micelle concentration is found to involve a sequence of diffusion, micellar relaxation and brush-limited processes.     

Single-Layer 2D Ni−BDC MOF Obtained in Supercritical CO2-Assisted Aqueous Solution

The development of an efficient strategy for fabricating two-dimensional metal-organic framework (MOF) nanosheets with high yield and high stability is desirable. Herein, we demonstrate for the first time that large, single-layer 2D nickel-benzene dicarboxylate (Ni−BDC) MOF nanosheets can be fabricated with the assistance of supercritical (SC) CO₂ in a pure aqueous system. Detailed experimental evidence reveals that the SC CO₂ molecule can exchange with the lattice-coordinated H₂O molecules, side-on coordinate with the metal Ni¹ sites on the Ni−BDC surface, and finally break the interlayer hydrogen bond to exfoliate the bulk Ni−BDC into a 2D MOF. More importantly, a thin SC CO₂ layer building up at the water−Ni−BDC interfaces can transform the pristine hydrophilic interface into a super-hydrophobic one. This super-hydrophobic layer at the water-MOF interface can effectively prevent dissociation, thus promoting the stability of Ni−BDC in aqueous system.