基于纳米TiO2的化学发光法检测核黄素

纳米TiO2与NaOH溶液作用能产生化学发光辐射,在表面活性剂十六烷基三甲基溴化铵(CTAB)的存在下,核黄素的加入能增强纳米TiO2-NaOH溶液的化学发光强度。基于此,构建了纳米TiO2-NaOH溶液化学发光新体系,建立了纳米TiO2-NaOH-核黄素体系检测核黄素的化学发光新方法。在优化实验条件下,核黄素质量浓度在5.0×10-6～3.5×10-4g/mL范围内与化学发光强度呈良好的线性关系,检出限为3.0×10-6g/mL,对2.5×10-5g/mL的核黄素进行11次平行测定,相对标准偏差为2.9%。该方法用于维生素B2片剂的测定,其结果与药典方法测得一致。该文同时对化学发光反应的机理进行了初步探讨。     

流动注射化学发光分析法测定利福平

在酸性条件下,KMnO4能氧化利福平产生弱化学发光,并且,利福平能极大的增敏Na2SO3-KMnO4体系的化学发光信号。基于此,结合流动注射技术,建立了测定利福平的新方法。在优化的条件下,利福平在5.0×10-8g/mL~1.0×10-5g/mL范围内与化学发光强度呈良好的线性关系,检出限为3×10-8g/mL。对2.0×10-6g/mL的利福平进行11次平行测定,相对标准偏差为2.6%。该法用于胶囊和滴眼液中利福平的测定,并初步探讨了该化学发光反应机理。     

FI-化学发光法间接测定维生素B1

提出利用Na2SO3的歧化反应与Luminol构建化学发光体系,并对其反应机理作了探讨.试验发现,Na2SO3在氢氧化钠碱性介质中发生歧化反应,其过渡态产物能与Luminol发生化学发光反应.维生素B1能使体系的发光强度减弱,化学发光强度的下降值(ΔI)与维生素B1的浓度在1.0×10-7～1.0×10-5mol·L-1范围内呈良好的线性关系,从而建立了测定维生素B1的流动注射化学发光新方法.方法的检出限为5.0×10-8mol·L-1.方法用于维生素B1片剂的测定.     

流动注射抑制电化学发光法测定维生素C

将在线恒电流电解产生ClO-与Luminol构成了较强的化学发光体系,基于维生素C对该化学发光体系有强抑制作用,结合流动注射技术,建立了测定维生素C的流动注射抑制电化学发光新方法.该方法在维生素C的浓度为2.0×10-10～1.5×10-8 mmol/mL之间分段回归,呈良好的线性,检出限达到5.0×10-11 mmol/mL.     

流动注射化学发光法测定阿莫西林

在碱性介质中,铁氰化钾能够氧化阿莫西林产生微弱的化学发光,Na2SO3对该体系有较强的增敏作用,据此,结合流动注射技术,建立了测定阿莫西林的新方法.阿莫西林在5.0×10-8～2.0×10-5 g/mL范围内与化学发光强度呈良好的线性关系,检出限为3×10-8 g/mL,对2.0×10-6 g/mL的阿莫西林进行11次平行测定,相对标准偏差为1.5%.本法已用于胶囊中阿莫西林的测定,并初步探讨了该化学发光反应的机理.     

流动注射电化学发光分析法测定维生素B1及在尿液分析中的应用

将在线恒电流电解产生ClO-与Luminol构成了较强的化学发光体系,基于维生素B1对该化学发光体系有抑制作用,结合流动注射技术,建立了测定维生素B1的流动注射电化学发光新方法,并把它应用于尿液分析中. 该方法在维生素B1的浓度为1.0×10-10～1.0×10-8 mmol/mL之间分段回归,呈良好的线性,检出限达到5.0×10-11 mmol/mL.     

高效液相色谱流动注射联用电化学发光法测定赣南脐橙中的维生素C

建立并应用了一种集高效液相色谱(HPLC)、流动注射(FI)和电化学发光三者优点于一体的HPLC-FI联用电化学发光分析新方法.方法基于将在线恒电流电解产生ClO-与Luminol构成了较强的化学发光体系,而维生素C对该化学发光体系有抑制作用,与流动注射技术相结合.该方法在维生素C的浓度为1.0×10-8～3.0×10-6 mmol/mL之间回归,呈良好的线性,检出限达到3.0×10-9 mmol/mL,回收率在93.6%～106.8%.     

Ru(bipy)2+3-CO2-3-SO2-3-KClO3体系化学发光法测定空气中的二氧化硫

提出了Ru(bipy) 2+ 3-CO 2- 3-SO 2- 3-KClO 3体系化学发光法测定溶液中亚硫酸盐的方法.SO 2- 3浓度与化学发光强度在1.0×10-7～1.0×10-4 mol/L 范围内成正比,检出限为8.76×10-8 mol/L,对1.0×10-4 mol/L SO2-3溶液6次测定的相对标准偏差为2.9%.该法用三乙醇胺作为吸收液,成功地用于测定空气中二氧化硫的含量,结果满意.     

MnO_2纳米溶胶-抗坏血酸化学发光反应的研究

在中性条件下利用Na2S2O3还原KMnO4制备出平均粒径约40 nmMnO2溶胶。研究发现,该溶胶在酸性条件下可氧化抗坏血酸产生化学发光。基于此,结合流动注射技术,对影响化学发光反应的各种因素进行了考察,建立了测定抗坏血酸的流动注射化学发光新方法。该方法测定抗坏血酸的线性范围为2.0×10-6~1.0×10-4g/mL,检出限为4×10-7g/mL,相对标准偏差为2.1%(1.0×10-5g/mL抗坏血酸溶液,n=11)。该方法已用于片剂中抗坏血酸的测定,结果与药典方法一致。     

抗癫痫药卡马西平的流动注射化学发光分析

在酸性条件下,卡马西平对KMnO4-Na2SO3化学发光体系具有明显的增敏作用,据此建立了流动注射化学发光测定卡马西平的新方法.该发光体系中,卡马西平质量浓度在1.0×10-9～1.0×10-6 g/mL 范围内与发光强度呈良好的线性关系,检出限为2.0×10-10g/mL,对1.0×10-7 g/mL 卡马西平进行11次平行测定,其相对标准偏差为0.9%.本方法已应用于片剂中卡马西平测定,并与药典方法进行了对照.     

Syntheses of 2-hydroperoxy-and 2-hydroxy-2H-imidazoles

Oxidation of fully substituted imidazoles 1 by singlet oxygen gives in good yield fully substituted 2-hydroperoxy-2H-imidazoles 2 . Reduction of 2 by triphenylphosphine leads to 2-hydroxy-2H-irnidazoles 3 . Limitations of the methods are reported.     

Crystal Structures of [Bu2Sn(O2PPh2)2], [Ph2Sn(O2PPh2)2], and [PhClSn(O2PPh2)OMe]2. Raman Spectra of [Ph2Sn(O2PPh2)2] and [PhClSn(O2PPh2)OMe]2

[(n‐Bu)₂Sn(O₂PPh₂)₂] ( 1 ), and [Ph₂Sn(O₂PPh₂)₂] ( 2 ) have been synthesized by the reactions of R₂SnCl₂ (R=n‐Bu, Ph) with HO₂PPh₂ in Methanol. From the reaction of Ph₂SnCl₂ with diphenylphosphinic acid a third product [PhClSn(O₂PPh₂)OMe]₂ ( 3 ) could be isolated. X‐ray diffraction studies show 1 to crystallize in the monoclinic space group P2₁/c with a = 1303.7(1) pm, b = 2286.9(2) pm, c = 1063.1(1) pm, β = 94.383(6)°, and Z = 4. 2 crystallizes triclinic in the space group , the cell parameters being a = 1293.2(2) pm, b = 1478.5(4) pm, c = 1507.2(3) pm, α = 98.86(3)°, β = 109.63(2)°, γ = 114.88(2)°, and Z = 2. Both compounds form arrays of eight‐membered rings (SnOPO)₂ linked at the tin atoms to form chains of infinite length. The dimer 3 consists of a like ring, in which the tin atoms are bridged by methoxo groups. It crystallizes triclinic in space group with a = 946.4(1) pm, b = 963.7(1) pm, c = 1174.2(1) pm, α = 82.495(6)°, β = 66.451(6)°, γ = 74.922(6)°, and Z = 1 for the dimer. The Raman spectra of 2 and 3 are given and discussed.     

Electrochemical study of (NEt4)2Cl2FeS2MoS2 and (NEt4)2Cl2FeS2MoS2FeCl2

Summary The ability of [MoS₄]^2–, anions to be used as ligands for transition metal ions has been widely demonstrated, especially with Fe²⁺. The present study has been restricted to linear complexes such as (NEt₄)₂ [Cl₂FeS₂MoS₂] and (NEt₄)₂[Cl₂FeS₂MoS₂FeCl₂]. Their electrochemical properties are described: upon electrochemical reduction, these compounds yield MoS₂, as a black precipitate, and an iron complex in solution, assumed to be [SFeCl₂]^2–. The electrochemical reduction goes through two electron transfers, coupled with the breakdown of the molecular skeleton: a DISPl and an ECE mechanism. Depending on the solvent, the following equilibrium may be observed: [Cl₄Fe₂MoS₄]^2–[Cl₂FeMoS₄]^2–+FeCl₂. The equilibrium constant, K_D, was evaluated by differential pulse polarography. K_D is tightly related to the donor number of the solvent.     

Photocycloaddition of 2-Cyanocycloalk-2-Enones to 2, 3-Dimethylbut-2-Ene

Irradiation of 5,5-dimethyl-6-oxocyclohex- l-ene- l-carbonitrile ( 1 ) in the presence of 2,3-dimethylbut-2-ene afforded 3,3,4,4,7,7-hexamethyl-3,4,4a,5,6,7-hexahydroindeno[1,7-c,d]-],2-oxazole (3) in nearly quantitative yield. In contrast, 4,4-dimethyl-5-oxo-cyclopent-l-ene-l-carbonitrile ( 2 ) under the same conditions reacted not to a tricyclic isoxazole but to a 2:1 mixture of 3,3,6,6,7,7-hexamethyl-2-oxo-bicyclo[3.2.0]heptane-l-carbonitrile ( 4 ) and trans-3,3-dimethyl-2-oxo-5-(2,3-dimethylbut-3-en-2-yl)cyclopentane-l-carbonitrile ( 5 ), respectively.     

Thermal decomposition of Me3SnO2PCl2, Me2Sn(O2PCl2)2 and Ph3SnO2PCl2

TG and DTA studies on Me₃SnO₂PCl₂, Me₂Sn(O₂PCl₂)₂ and Ph₃SnO₂PCl₂ were carried out under dynamic argon atmosphere. The results show that the decomposition proceeds in different stages leading to the formation of Sn₃(PO₄)₂ as a stable product. This compound was characterized by IR spectroscopy. Decomposition schemes involving reductive elimination reactions were proposed.     

Efficient C2 functionalisation of 2H-2-imidazolines

Alkylation and oxidation of 2H-2-imidazolines, followed by regioselective deprotection, thionation and microwave-assisted Liebeskind-Srogl reaction, efficiently led to 2-aryl-2-imidazolines as new analogues of p53-hdm2 interaction inhibitors (Nutlins).