Determination of acetone, hexanal and heptanal in blood samples by derivatization with pentafluorobenzyl hydroxylamine followed by headspace single-drop microextraction and gas chromatography–mass spectrometry

In the study, we developed a simple, rapid, sensitive, and inexpensive method for determination of the disease biomarkers of acetone, hexanal and heptanal in human blood. For the first time, derivatization of carbonyls with O-2,3,4,5,6-(pentafluorobenzyl)hydroxylamine (PFBHA) was combined with headspace single-drop microextractin (HS-SDME) and gas chromatography-mass spectrometry (GC–MS) and applied to the analysis of acetone, hexanal, and heptanal in human blood. At first, acetone, hexanal and heptanal in blood were derivatized with PFBHA and formed oximes in several seconds. Sequentially, the oximes were headspace extracted and concentrated by a microdrop solvent. Finally, the extracted oximes were analyzed by GC–MS. HS-SDME conditions and method validations were studied. Due to needing of only 2 μl organic solvent, short extraction time of 8 min, and simple operation, derivatization-HS-SDME was shown to be a rapid, simple, and inexpensive technique for analysis of acetone, hexanal, and heptanal in human blood. Moreover, it had low detection limit values from 0.24 to 0.62 nM, and good reproducibility (R.S.D. less than 12%).     

碘离子选择电极在动力学分析中的应用 Ⅰ.催化电势动力学测锆法研究

本文报道采用碘离子选择电极,系统研究了锆于BO_3~--I~-反应中的定量催化特性,建立了催化电势动力学间接测痕量锆的方法。结果表明,本法专属性较高,55种阴、阳离子均不干扰测锆。     

电动势法测定Cu(Ⅰ)与乙炔生成配合物的热力学函数

乙炔与Cu(I)生成配合物的热力学函数文献报道鲜见,且不同作者的测定结果差异较大。本文用改进的电动势法。对在氯丁橡胶、聚氯乙烯,乙醛等工业过程有重大意义的Cu(I)与乙炔配合物进行测定,得到更合理的结果。     

A concise synthesis of nornitidine via nickel- or palladium-catalyzed annulation

A concise method to synthesize benzo[c]phenanthridine alkaloid, nornitidine, was developed utilizing nickel- or palladium-catalyzed iminoannulation of an internal alkyne. The advantages of this strategy included readily available starting materials, inexpensive reagents, short reaction steps, and good yields.     

Selective Oxidation of Isobutene over CsFeCoBiMnMoOx Mixed Oxide Catalyst

Mixed oxide catalyst Cs0.1Fe2Co6BiMnMo12Ox was prepared by the coprecipitation method.Selective oxidation of isobutene was carried out in a fixed-bed reactor over Cs0.1Fe2Co6BiMnMo12Ox.The results showed that the catalyst had high catalytic activity. Under the optimum reaction conditions(n(i-C4):n(O2)=1:2-1:4, space velocity=180 h^-1, T=360℃), the yields of methacrolein and methacrylic acid can reach 80% and 8%, respectively. The total yield of liquid products (methacrolein, methacrylic acid and acetic acid) can reach about 90%.     

The determination of intrinsic reaction coordinates by density functional theory

The first implementation of the intrinsic reaction coordinate (IRC ) method within the density functional theory (DFT ) framework is presented. The implementation has been applied to four different types of chemical reactions represented by the isomerization process, HCN ? HNC (A); the S_N2 process, H^? + CH₄ ? CH₄ + H^? (B); the exchange process, H˙ + HX ? HX + H˙ (X ? F,Cl) (C); and the elimination process, C₂H₅Cl ? C₂H₄ + HCl (D). The present study presents for each process optimized structures and calculated harmonic vibrational frequencies for the reactant(s), the transition state, and the product(s) along with the IRC path connecting the stationary points. The calculations were carried out within the local density approximation (LDA ) as well as the LDA/NL scheme where the LDA energy expression is augmented by Perdew's and Becke's nonlocal (NL ) corrections. The LDA and LDA/NL results are compared with each other as well as the best available ab initio calculations and experimental data. For reaction (D), ab initio calculations based on MP 2 geometries and MP 4SDTQ energies have been added due to the lack of accurate published post-HF calculations on this process. A detailed discussion is provided on the efficiency of the IRC algorithms, the relative accuracy of the DFT and ab initio schemes, as well as the reaction mechanisms of the four reactions. It is concluded that the LDA/NL scheme affords the same accuracy as does the MP 4 method. The post-HF methods seem to overestimate activation energies, whereas the corresponding LDA/NL estimates are too low. The LDA activation energies are even lower than the LDA/NL counterparts. The incorporation of the IRC method into the DFT framework provides a promising and reliable tool for probing the chemical reaction path on the potential energy surfaces, even for large-size systems. IRC calculations by ab initio methods of an accuracy similar to the LDA/NL scheme, such as the MP 4 scheme, are not feasible. © John Wiley & Sons, Inc.     

二苄亚砜硝酸钕的晶体结构

二苄亚砜硝酸钕Nd(NO_3)_3·[(C_6H_5CH_2)_2S0]属三斜晶系,P1空间群,晶胞参数:a=9.835(2),b=12.445(2),c=19.971(5)A,α=104.13(2)°,β=90.34(2)°γ=74.96(1)°Z=2。晶体结构用重原子法解出,经最小二乘修正后R因子为0.031。钕离子由九个氧配位,形成稍歪扭的三帽三方棱柱配位多面体,其中一个三角面由三个二苄亚砜(DBSO)提供的氧形成,其他氧原子则由硝酸根提供。平均Nd-O(DBSO)=2.379A,Nd-O(NO_3)=2.536A。     

新型铕双β-二酮红光材料的合成与发光性质

通过分子设计,合成了一种新颖的双β-二酮有机配体9-乙基-3,6-二（乙酰基-3-苯甲酰基）咔唑（H2L）及其铕配合物,红外光谱和电子光谱表明Eu^3＋与H2L发生配位。配合物的溶液荧光光谱不仅有613 nm处的中心离子Eu^3＋的特征红光,属^5D0→^7F2跃迁带,还有445nm处配体的宽带蓝色发光,属H2L^＊→H2L跃迁带,而配合物的光致发光光谱只有611 nm处为中心离子Eu^3＋的特征红光,属^5D0→^7F2跃迁带,峰形尖锐,半峰宽仅7 nm,单色性好,表明该固体铕双β-二酮配合物是一种潜在的红色发光材料。     

Homogeneous chemiluminescence system in neutral and near neutral aqueous solution with ClO2 as oxidant and its analytical application

Using ClO₂ as chemiluminescence (CL) oxidant, a novel homogeneous CL system in neutral and near neutral aqueous solution is proposed in this paper. ClO₂ could oxidize sulfite in pH 5.0–8.5 acetate buffer to produce CL emission, and pipemidic acid could sensitize the CL system. The ClO₂–SO₃²⁻–pipemidic acid reaction was used as a model CL system and explored the possibility of highly active and eco-friendly ClO₂ being used as CL oxidant in neutral and near neutral aqueous solution. Combined with flow-injection analysis, the proposed CL system was applied to the automated dissolution testing of pipemidic acid tablet. Compared with the common strong acidic or strong basic CL system, this proposed CL owns its advantages.