激光解吸电离质谱法分析富勒烯

论述了用激光解吸电离谱法分析富勒烯。因在电离过程中富勒分子不发生裂解，因此这种方法可直接用于富勒烯混合物的分析而勿需任何预分离。还给出了用本法分析较大、较稳定富勒烯分子的质谱图。     

Novel one-dimensional tubelike and two-dimensional polycatenated metal-organic frameworks

Two novel metal-organic frameworks (MOFs) [Zn(TITMB)(OAc)](OH).8.5H(2)O (1) and [Ag(TITMB)N(3)].H(2)O (2) [TITMB = 1,3,5-tris(imidazol-1-ylmethyl)-2,4,6-trimethylbenzene, OAc = acetate anion] were synthesized and their structures were determined by X-ray crystallography. Complex 1 crystallizes in tetragonal space group P(-)4 with a = 23.2664(7) and c = 11.9890(3) A and Z = 8. 1 has a one-dimensional tubelike structure with large inner pore size of approximately 17 A. Complex 2 crystallizes in monoclinic space group C2 with a = 20.7193(10), b = 11.5677(8), and c = 12.2944(6) A, beta = 125.5770(10) degrees, and Z = 4. 2 consists of two-dimensional honeycomb networks that interpenetrate each other to generate a polycatenated structure. In these two complexes, both zinc(II) and silver(I) atoms are four-coordinated with the same tetrahedral coordination geometry. The topologies of 1 and 2 are predominated by the conformations of TITMB, which are cis, trans, trans in 1 and cis, cis, cis in 2, respectively.     

Arsenic speciation based on ion exchange high-performance liquid chromatography hyphenated with hydride generation atomic fluorescence and on-line UV photo oxidation

An on-line method capable of the separation of arsenic species was developed for the speciation of arsenite As(III), arsenate As(V), monomethylarsenic (MMA) and dimethylarsenic acid (DMA) in biological samples. The method is based on the combination of high-performance liquid chromatograph (HPLC) for separation, UV photo oxidation for sample digestion and hydride generation atomic fluorescence spectrometry (HGAFS) for sensitive detection. The best separation results were obtained with an anion-exchange AS11 column protected by an AG11 guard column, and gradient elution with NaH2PO4 and water as mobile phase. The on-line UV photo oxidation with 1.5% K2S2O8 in 0.2 mol L(-1) NaOH in an 8 m PTFE coil for 40 s ensures the digestion of organoarsenic compounds. Detection limits for the four species were in the range of 0.11-0.15 ng (20 microL injected). Procedures were validated by analysis of the certified reference materials GBW09103 freeze-dried human urine and the results were in good agreement with the certified values of total arsenic concentration. The method has been successfully applied to speciation studies of blood arsenic species with no need of sample pretreatment. Speciation of arsenic in blood samples collected from two patients after the ingestion of realgar-containing drug reveals slight increase of arsenite and DMA, resulting from the digestion of realgar.     

Dynamic ultrasound-assisted extraction of polyphenols in tobacco

A novel extraction method, namely dynamic ultrasound-assisted extraction, is investigated. This technique is efficient with respect to both time and solvent consumption because it utilizes ultrasonic energy in dynamic mode during extraction. Polyphenols (chlorogenic acid, esculetin, rutin, scopoletin, and quercitrin) are extracted from a tobacco (Nicotina tobaccum L.) sample for 10 min with 6 mL of solvent. Fresh solvent is continuously pumped through the sample, with which the analytes can be rapidly extracted, and the possibility of degradation efficiently avoided. Methanol involving 0.5% w/v ascorbic acid was used as extraction solvent; optimal flow rate and extraction time were investigated. The extract was cleaned up by C18 disposable cartridge. The spiked and nonspiked tobacco samples were used for the evaluation of the proposed method. Recoveries obtained were varied from 96 to 108% and RSDs from 2.0 to 4.6%. This extraction technique was revealed to recover larger amounts of polyphenols from tobacco, compared to the static ultrasound-assisted extraction method.     

钯-8-羟基喹啉-5-磺酸络合物电极反应和十二烷基硫酸钠的增敏机理

钯 8 羟基喹啉 5 磺酸形成的络合物的峰电流 (pH 8.6 ,- 0 .6 8V)具有吸附特性 ,为不可逆电极反应过程。其电子转移数 (n)、电子转移系数 (α)及饱和吸附量 (Γs)分别为 2、0 .4 6和 2 .2× 10 - 9mol cm2 ;钯 与8 羟基喹啉 5 磺酸的络合比为 1∶2 ;稳定常数 (K)为 8.73× 10 7。加入阴离子表面活性剂十二烷基硫酸钠未形成三元络合物 ,催化电流是由与十二烷基硫酸钠共吸附在电极表面上的超氧阴离子自由基氧化了络合物的电极反应中间体所产生的。     

人尿中异黄酮的高效液相色谱分析

建立了测定人尿中异黄酮组分(大豆苷原、黄豆黄素、雌马酚、染料木黄酮)含量的反相高效液相色谱法。在尿样中加入黄酮作为内标,异黄酮经酶解后在pH=7.0中性条件下用乙酸乙酯(1∶1)提取,然后用0.02%TFA-M eOH-ACN三元梯度洗脱的方法分离异黄酮。在该条件下,大豆苷原、黄豆黄素、雌马酚、染料木黄酮的检出限分别为12.9 nmol/L、13.9 nmol/L、71.6 nmol/L和11.8 nmol/L;回收率均在89%以上。本方法具有测试步骤简单、准确度高、重现性好等优点,适合大批量样品测定。     

Two New Pyrrolizidines from Ligularia lankongensis

Two new pyrrolizidines named lankongensisine A (1), B (2) were isolated from the roots of Ligularia lankongensis collected in Lijiang, Yunnan, and their structures were established by spectroscopic analysis.     

Novel transition metal oxalatophosphates with a two-dimensional honeycomb structure: (H3TREN)[M2(HPO4)(C2O4)2.5] x 3H2O (M = Mn(II) and Fe(II), TREN = tris(2-aminoethyl)amine)

Two new layered transition metal oxalatophosphates, (H(3)TREN)[M(2)(HPO(4))(C(2)O(4))(2.5)].3H(2)O (M = Mn(II) and Fe(II)), have been synthesized by hydrothermal methods in the presence of a structure-directing organic amine, tris(2-aminoethyl)amine, and characterized by single-crystal X-ray diffraction and magnetic susceptibility. They are the first metal oxalatophosphates which adopt a two-dimensional honeycomb structure with the organic cations and water molecules intercalated in between. Within a layer, there are 12-membered pores made from 6 Mn, 1 phosphate, and 5 oxalate units. Measurements of field dependence of magnetization and variable-temperature susceptibilities under different fields were performed on a polycrystalline sample of the manganese compound. The results indicate a phase transition from a paramagnetic to an antiferromagnetic coupled state at about 12 K. Crystal data for the manganese compound follow: triclinic, space group Ponemacr; (No. 2), a = 8.8385(6) A, b = 9.0586(6) A, c = 16.020(1) A, alpha = 77.616(1) degrees, beta = 83.359(1) degrees, gamma = 68.251(1) degrees, and Z = 2. Crystal data for the iron compound are the same as those for the manganese compound except a = 8.7776(9) A, b = 8.9257(9) A, c = 15.884(2) A, alpha = 78.630(2) degrees, beta = 84.018(2) degrees, and gamma = 67.372(2) degrees.     

[Co(ptma)(amp)Cl]2+体系的一反式经式异构体(m3[ZnCl4]·0.5H2O)的晶体结构

在合成[Co(bpma)(tn)Cl]²⁺体系配合物的实验中,得到[Co(ptma)(amp)Cl]²⁺体系的一反式(ptma中仲胺上的氢相对于Cl)经式异构体(m3[ZnCl₄]·0.5H₂O),其中bpma=N,N′-二(2-吡啶基甲基)胺,tn=1,3丙二胺,ptma=N-(2-吡啶基甲基)丙二胺,amp=2-(氨基甲基)吡啶。此配合物异构体构型选择性形成的原因可能主要是其结构中配体间C-H…π相互作用使之更稳定的结果。利用单晶X-射线衍射法测定的晶体学参数:单斜晶系,空间群C2/c,a=1.55978(19)nm,b=1.33324(16)nm,c=2.2077(3)nm,β=94.832(3)°,V=4.5748(10)nm³,D_c=1.696g·cm^-3,Z=8,F₀₀₀=2360,μ(MoKα)=23.72cm^-1,R=0.0475,R_w=0.1204。配合物离子中Co³⁺为六配位。晶胞中含8个配合物阳离子,8个[ZnCl₄]^2-阴离子及4个水分子,对映体的比例为1∶1。     

四足配体铽配合物-蒙脱土超分子复合发光材料的插层组装、表征和性质研究

用两种方法分别将四足配体铽配合物[TbL（NO3）]^2＋和[TbL]^3＋插层组装到了蒙脱土（MT）层板间，制备出超分子复合发光材料[TbL（NO3）^2＋-MT和[TbL]^3＋-MT。方法一：通过离子交换反应让配离子[TbL（NO3）]^2＋取代钠＋基蒙脱土（Na-MT）中的Na^＋离子，插层组装到蒙脱土层板间。方法二：用配体L与铽基蒙脱土（Tb-MT）反应，使配体插入蒙脱土层板间与Tb^3＋离子配位。用元素分析、XRD，FT-IR,UV-vis和热分析对材料进行了表征，并对其荧光性质进行了研究。结果表明，复合材料保持了蒙脱土良好的层柱结构特征，其层间距d001值与插层配离予的直径吻合较好，配离子以单层形式分布于蒙脱土层板间，复合材料中配合物的热稳定性有明显提高。在紫外光激发下，复合材料发出较强的Tb^3＋特征荧光，其发射光谱与相应配合物的发射光谱很相似；复合材料中配合物的相对荧光强度较相应纯配合物有明显提高。荧光寿命较长；配合物的激发波长向可见光区发生位移，说明插层组装实现了对配合物激发波长的调制作用。