微波消解-毛细管电泳法测定茶叶中的生物碱

应用微波消解-毛细管电泳法测定3种茶叶中的咖啡因、腺嘌呤及儿茶素类化合物.优化了缓冲溶液体系、浓度、pH及分离电压等实验条件.在最佳实验条件下,以30 mmol/L硼砂-10 mmol/L β-环糊精为缓冲溶液,pH为9.0,分离电压为22 kV,检测波长为280 nm,电动进样20 kV×5s时,在7 min内同时分...     

微流控芯片非接触电导法分离检测5种阳离子

建立了微流控芯片非接触电导法快速分离检测5种常见阳离子的分析方法。考察了缓冲溶液的种类、浓度和pH、添加剂、检测器的激发电压和激发频率等因素对离子分离及检测的影响。根据离子的峰高和信噪比(S/N),研究了非接触电导检测器的激发电压和激发频率对不同阳离子检测的影响规律。以pH 3.8的15 mmol/L精氨酸(Arg)+15 mmol/L酒石酸+2 mmol/L18-冠醚-6+10%(V/V)甲醇作为运行缓冲液,检测器激发电压100 Vp-p、激发频率40 k Hz,可在70 s内实现NH~+_4,K~+,Na~+,Mg~(2+)和Ca~(2+)的分离检测,5种离子的迁移时间重现性RSD均在1.5%以内。结果还表明,非接触电导检测器激发电压和激发频率对5种阳离子检测的影响规律和最佳检测条件基本相同。     

毛细管电泳电致化学发光法测定家犬体内甲氧氯普胺的血药浓度

基于甲氧氯普胺对钌联吡啶电化学发光信号的增敏作用, 建立了检测甲氧氯普胺的毛细管电泳电致化学发光新方法. 最佳实验条件为: 检测电位1.18 V, 钌联吡啶浓度5 mmol/L, 检测池磷酸缓冲溶液40 mmol/L (pH 7.2), 分离磷酸缓冲溶液20 mmol/L (pH 6.1), 进样电压12 kV, 进样时间10 s, 分离电压14 kV. 方法的检测限(3σ)为5.0×10^－3 mg/L, 线性范围为 0.03～9.52 mg/L, 相关系数为0.9990, 回收率为98.0%～101.7%. 对家犬体内甲氧氯普胺血药浓度的监测发现, 给药1.5 h血药浓度达到最大值, 血药浓度的半衰期约为4 h. 本方法具有简便、快速、灵敏、进样量少等特点, 可用于甲氧氯普胺血药浓度监控和药物动力学研究.     

高效毛细管电泳安培法测定肉苁蓉中松果菊苷的含量

采用毛细管电泳安培法建立了肉苁蓉中松果菊苷含量的检测方法,探讨了缓冲溶液种类、工作电位、分离电压、进样时间等对分离和检测的影响.在15 mmol/L硼砂缓冲溶液(pH 9.5),25 kV电压,0.6 V工作电位的条件下,松果菊苷的质量浓度在0.5～50.0 mg/L范围内与峰面积呈良好线性,相关系数为0.9994,检...     

乙醛酸和草酸的毛细管区带电泳分析

建立了同时测定乙醛酸和草酸的毛细管区带电泳法。考察了缓冲溶液的种类、浓度和pH以及分离电压等因素对分离结果的影响。在缓冲溶液为20 mmol/L硼砂-5.5 mmol/L邻苯二甲酸氢钾(pH 9.0)、分离电压20 kV、检测波长212 nm的优化条件下,11 min内即可实现对目标物的分离。乙醛酸和草酸分别在0.8～20 g/L和1.2～20 g/L范围内线性关系良好,相关系数分别为0.9993和0.9975;方法的检出限分别为0.2和0.4 g/L(信噪比为3);样品的加标回收率为98.3%～102.5%,相对标准偏差为0.35%～0.61%。该方法操作简便、快速、成本低廉,已应用于实际样品的分析,并获得了令人满意的结果。     

毛细管电泳电容耦合非接触电导检测-双端进样同时测定无机阴离子和阳离子

利用自研制的电容耦合非接触电导检测器，结合毛细管电泳技术，以2-N-吗啡啉乙磺酸(MES)／组氨酸(His)为缓冲溶液，采用双端进样方式，同时分离测定了5种阴离子和7种阳离子。考察了激发电压值、激发电压频率对检测的影响；缓冲溶液浓度及pH、进样操作对分离的影响。在最佳分离检测条件下，12种无机离子可在4min内完成测定。阳离子的检出限为0．2(Na^ )-3μmol／L(Mn^2 )；阴离子的检出限为0．5(SO4^2-)-4μmol／L(Br^-)；线性范围可达两个数量级。方法用于实际水样中阴离子和阳离子的测定。     

以卡那霉素为选择剂对盐酸地匹福林的毛细管电泳拆分

本研究以卡那霉素作为手性选择剂,采用毛细管电泳法对盐酸地匹福林对映体进行手性拆分,并对分离条件进行优化。考察了卡那霉素的浓度、缓冲溶液pH值、柱温及有机添加剂等因素对分离的影响。优化分离条件为:卡那霉素浓度0.6%;有机添加剂5%:乙腈-甲醇混合物(体积比9∶1);20mmol/L pH=2的磷酸盐缓冲溶液;进样:25psi×2s;分离电压+20kV;检测波长262nm;柱温25℃。在此优化分离条件下,盐酸地匹福林实现基线分离。该方法操作简便,可用于盐酸地匹福林对映体的分离。     

苯二酚异构体电迁移行为预测与研究

系统研究了邻、间、对苯二酚3种异构体在毛细管区带电泳中的迁移行为,从理论上分析了解离常数、缓冲液pH与迁移行为之间的关系,进行了定量预测。通过实验讨论了缓冲溶液类型及浓度、缓冲溶液的pH、分离电压等因素对三种异构体分离的影响,获得了优化的分离条件。结果表明,使用未涂层石英毛细管柱(50μmi.d.,50 cm,有效长度为45 cm),在检测波长225 nm,硼砂缓冲溶液30 mmol/L,pH为8.5~9.15,分离电压为10~25 kV的条件下,苯二酚3种异构体均可按对、间、邻的顺序得到基线分离,实验结果与理论预测相符。     

硫酸沙丁胺醇的毛细管电泳非接触电导法检测

建立了毛细管电泳-非接触电导检测分离测定硫酸沙丁胺醇的分析方法。分别考察了分离介质、背景电解质及其浓度和pH、分离电压、进样时间、激发电压、激发频率等因素对实验结果的影响。在优化的实验条件(以15 mmol/L乳酸水溶液(pH 2.7)为电泳介质,10 kV下电动进样3 s,分离电压为10 kV,激发电压为60 V,激发频率为120 kHz)下,硫酸沙丁胺醇的检出限(信噪比为3)为1.92 mg/L,在9.60～48.0 mg/L质量浓度范围内有良好的线性关系(r=0.995),迁移时间的相对标准偏差(RSD)为2.7%。将该方法用于硫酸沙丁胺醇片和硫酸沙丁胺醇气雾剂中的硫酸沙丁胺醇含量的测定,加标回收率为90%～113%,检测结果与药厂的标示值相符合,为硫酸沙丁胺醇的检测提供了一种简便、快速、高灵敏的方法。关键词: 毛细管电泳;非接触电导检测法;硫酸沙丁胺醇;硫酸沙丁胺醇片;硫酸沙丁胺醇气雾剂     

硫酸阿米卡星的毛细管电泳法快速测定

建立了毛细管电泳高频电导法快速测定注射液中硫酸阿米卡星的新方法.考察了缓冲溶液、有机溶剂添加剂以及分离电压和进样条件等因素对分离检测的影响.采用5.0 mmol/L乳酸-30%(体积分数)乙醇缓冲液体系为运行电泳介质,分离电压20.0 kV,在最佳实验条件下,5.5 min内即可实现硫酸阿米卡星的分离检测,硫酸阿米卡星的线性范围为5.00 ～150 mg/L,检出限为1.5 mg/L.     

Synthesis and structure of hydroxyisoxazolidines and derivatives of hydroxylamine and alkenals

The reactions of N-substituted hydroxylamines with alkenals serve as a method for the synthesis of the corresponding 2-substituted 3(5)-hydroxyisoxazolidines. The reaction pathway is determined by the nature of the substituent attached to the nitrogen atom. Ring-chain isomerism has been detected in these newly obtained compoundsTranslated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1270–1276, September, 1987.     

Investigation of adhesion and mobility of polyurethane and epoxy-rubber glues and adhesives

The values of activation parameters in uncured and cured epoxy resins, rubbers, and blends thereof are investigated. The dependences of activation energy and adhesion strength of epoxy-rubber compositions on rubber content are determined. The correlation of adhesion and activation energy values for polyurethane rubber and epoxy-rubber compositions is shown.     

Mass and NMR spectra of haplophyllidine and perforine and of their derivatives

Conclusions The mass and NMR spectra of haplophyllidine, perforine, and their derivatives have been studied. The influence of the open and cyclic forms of the molecular ion on the nature of the fragmentation has been discussed. The main routes of fragmentation of the compounds considered are due to the presence of substituents at C₈ and C₄.Khimiya Prirodnykh Soedinenii, Vol. 5, No. 4, pp. 273–279, 1969     

Crystal and molecular structure of aroyl- and acetylhydrazones of acet- and benzaldehydes

Aroyl- and acetylhydrazones of acet- (I) and benzaldehydes (IV) and benzoylhydrazones of acet- (II) and benzaldehydes (III) were studied by x-ray structural and quantum-chemical methods in order to establish their structures. Compund (I) was the EEZ structure in the crystal. Calculations and spectral data showed that the EEE form occurs in nonpolar solvents and in the gas phase. According to crystallographic data molecules (I)–(IV) are the E-isomers (relative to the N-N bond) and the hydrazone fragments are planar. Intermolecular N-H...O H-bonds from in the crystals. The data obtained suggest that the majority of acylhydrazones are conformationally rigid on dissolution although exceptions do occur. Apparently the reasons for the difference of acetyl- and benzoylhydrazones in electrocarboxylation reactions are electronic and not steric factors.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 75–81, January, 1991.     

Synthesis and characterization of triazenide and triazene complexes of ruthenium and osmium

Triazenide [M(eta2-1,3-ArNNNAr)P4]BPh4 [M = Ru, Os; Ar = Ph, p-tolyl; P = P(OMe)3, P(OEt)3, PPh(OEt)2] complexes were prepared by allowing triflate [M(kappa2-OTf)P4]OTf species to react first with 1,3-ArN=NN(H)Ar triazene and then with an excess of triethylamine. Alternatively, ruthenium triazenide [Ru(eta2-1,3-ArNNNAr)P4]BPh4 derivatives were obtained by reacting hydride [RuH(eta2-H2)P4]+ and RuH(kappa1-OTf)P4 compounds with 1,3-diaryltriazene. The complexes were characterized by spectroscopy and X-ray crystallography of the [Ru(eta2-1,3-PhNNNPh){P(OEt)3}4]BPh4 derivative. Hydride triazene [OsH(eta1-1,3-ArN=NN(H)Ar)P4]BPh4 [P = P(OEt)3, PPh(OEt)2; Ar = Ph, p-tolyl] and [RuH{eta1-1,3-p-tolyl-N=NN(H)-p-tolyl}{PPh(OEt)2}4]BPh4 derivatives were prepared by allowing kappa1-triflate MH(kappa1-OTf)P4 to react with 1,3-diaryltriazene. The [Os(kappa1-OTf){eta1-1,3-PhN=NN(H)Ph}{P(OEt)3}4]BPh4 intermediate was also obtained. Variable-temperature NMR studies were carried out using 15N-labeled triazene complexes prepared from the 1,3-Ph15N=N15N(H)Ph ligand. Osmium dihydrogen [OsH(eta2-H2)P4]BPh4 complexes [P = P(OEt)3, PPh(OEt)2] react with 1,3-ArN=NN(H)Ar triazene to give the hydride-diazene [OsH(ArN=NH)P4]BPh4 derivatives. The X-ray crystal structure determination of the [OsH(PhN=NH){PPh(OEt)2}4]BPh4 complex is reported. A reaction path to explain the formation of the diazene complexes is also reported.     

Glycolate and Thioglycolate Complexes of Rhenium and Their Oxidative Elimination of Ethylene and of Glycol

Selenium dioxide and osmium tetroxide are effective reagents and catalysts for olefin oxidation, although, owing to their toxicity, reservations remain as to their applicability.^[1] We are therefore seeking more easily handled metal oxides that are soluble in organic solvents and that are as effective as osmium tetroxide in carrying out stereospecific cis hydroxylation of olefins. The rhenium(VII ) oxide 1 , which has meanwhile become readily accessible, is a favorable candidate.^[2]     

The chemical transport of molybdenum and tungsten and of their dioxides and sulfides

Experiments have been made and an extensive thermodynamic discussion has taken place concerning the chemical transport of Mo, W, MoO₂, WO₂, MoS₂ and WS₂ in the presence of iodine. Efforts have been made to find the species via which Mo and W can migrate within the gas phase.Results: In each case the transport proceeds via the oxide iodides MoO₂J₂ and WO₂J₂ respectively, as already known for the dioxides. Thus the chemical transport of Mo, W, MoS₂ and WS₂ needs not only J₂ but also H₂O, usually liberated from the wall of the quartz ampoule.By means of J₂ + H₂O, the metals can be transported into the high temperature region of the ampoule (e.g., 1050 → 1150°C), whereas the transport of the sulfides proceeds in the opposite direction (e.g., 900 → 700°C).For the sulfide-transport the influence of the ratio of the transport agents $\text{J}{}_2\text{H}{}_2\text{O}$ has been discussed.The water content of the quartz glass out of which the ampoules are made is an important source for water, influencing the reactions.The addition of graphite which considerably lowers the H₂O partial pressure prevents any transport of the metals or the sulfides, which proves that the use of J₂ alone as a transport agent is insufficient in these cases.The gaseous iodides MoJ_x and WJ_z are without any importance under the experimental conditions used for the transport of the metals, their dioxides and sulfides.The partial pressures of MoO₂(OH)₂ and WO₂(OH)₂ under the experimental conditions chosen may usually be neglected. But in the system $\text{MoO}{}_2\text{H}{}_2\text{O}$ the transport via MoO₂(OH)₂ (1000 → 800°C) has been observed.The synthesis of MoO₂ and WO₂, starting with the elements or with powder of metal and trioxide is promoted by the addition of J₂. The reaction steps involved are discussed.