铕和铽与3,4-呋喃二甲酸双核配合物的合成、表征及其晶体结构

本文首次合成了铕(Ⅲ)和铽(Ⅲ)与3,4-呋喃二甲酸配合物,研究了它们的IR、DTA、TG、DTG和荧光光谱等性质,并完成了单晶的晶体分析。结果表明,配合物为〔Ln·HL_2(H_2O)_2〕_2·2H_2O(Ln=Eu(Ⅲ),Tb(Ⅲ);H_2L=3,4-呋喃二甲酸),属单斜晶系,P2/c空间群,Z=2,晶胞参数对铕和铽配合物分别为α=10.842(1),10.801(4);b=8.725(2),8.664(2);c=16.366(4),16.308(6)A;β=93.50(1),93.67(3)°;V=1545.3(5),1523.0(8)A~3。

Unprecedented 5,5-connected (4(7)center dot 6(3)) (4(8)center dot 6(2)) structural topology: A lead biphosphonate with double layered structure

A new lead(II) phosphonate, Pb[(PO3)(2)C(OH)CH3]center dot H2O (1) was hydrothermally synthesized and characterized by IR, elemental analysis, UV, TGA, SEM, and single crystal X-ray diffraction analysis. X-ray crystallographic study showed that complex 1 has a two-dimensional double layered hybrid structure containing interconnected 4- and 12-membered rings and shows an unusual (5,5)-connected (4(7) . 6(3)) (4(8) .6(2)) topology. (C) 2008 Elsevier B.V. All rights reserved.

Comparative analysis of allantoin quercetin, and 1-methyl-1,2,3,4-tetrahydro-beta-carboline-3-carboxylic acid in Nitraria tangutorum Bobr. Seed by HPLC-APCI-MS and CE

This paper describes the simultaneous determination of allantoin, quercetin, and 1-methyl-1,2,3,4-tetrahydro-beta-carboline-3-carboxylic acid (MTCCA) in Nitraria tangutorum Bobr seed by HPLC-APCI-MS and CE (capillary electrophoresis) methods. The final optimized chromatographic conditions were investigated in a reversed-phase Eclipse XDB-C8 column (150 x 4.6 mm, 5 mu m). A seventeen-minute gradient elution, (A: aqueous acetonitrile 20% (v/v); B: aqueous acetonitrile 60% (v/v); C: pure acetonitrile 100%) at a flow rate of 1.0 mL/min was selected for the separation of three natural products with diode array detection (DAD) at 220 nm. A CE experiment was carried out in a fused silica capillary with 32 mmol/L boric acid (pH 10), 32 mmol/L SDS and acetonitrile (10.0%, v/v). The applied potential and temperature was, respectively, set at 19 kV and 25 degrees C. After development, the validation was performed in parallel for HPLC and CE, with the same standards and sample to avoid differences due to the manipulation. The validation parameters of both techniques were adequate for the intended purpose.

Pre-column derivatization of amines with 1,2-benzo-3,4-dihydrocarbazole-9-isopropyl chloroformate followed by LC-fluorescence and LC-APCI-MS

A pre-column derivatization method for the sensitive determination of amines using the labeling reagent 1,2-benzo-3,4-dihydrocarbazole-9-isopropyl chloroformate (BCIC-Cl) followed by high-performance liquid chromatography with fluorescence detection has been developed. Identification of derivatives is carried out by high performance liquid chromatography/atmospheric pressure chemical ionization (LC-APCl-MS-MS). The chromophore of 2-(9-carbazole)-ethyl chloroformate (CEOC) reagent is replaced by 1,2-benzo-3,4-dihydrocarbazole-9-isopropyl functional group, which results in a sensitive fluorescence derivatizing reagent BCIC-Cl. BCIC-Cl can easily and quickly label amines. Derivatives are stable enough to be efficiently analyzed by high-performance liquid chromatography and show an intense protonated molecular ion corresponding m/z [MH](+) under APCl in positive-ion mode. The collision-induced dissociation of protonated molecular ion formed a product at m/z 260 corresponding to the cleavage of CH2-OCO bond. Studies on derivatization demonstrate excellent derivative yields over the pH 9.0-10.0. Maximal yields close to 100% are observed with a 3 to 4-fold molar reagent excess. In addition, the detection responses for BCIC derivatives are compared with those obtained using CEOC and FMOC as derivatization reagents. The ratios of l(BCIC)/l(CEOC) and l(BCIC)/l(FMOC) are, respectively, 1.23-3.14 and 1.25-3.08 for fluorescent (FL) responses (here, l is relative fluorescence intensity). Separation of the derivatized amines had been optimized on reversed-phase Eclipse XDB-C-8 column. Detection limits are calculated from 1.0 pmol injection, at a signal-to-noise ratio of 3, are 10.6-37.8 fmol. The mean interday accuracy ranges from 94 to 105% for fluorescence detection with the largest mean %CV < 7.5. The mean interday precision for all standards is < 6.0% of the expected concentration. Excellent linear responses are observed with coefficients of > 0.9997.

Development of a sensitive fluorescent derivatization reagent 1,2-benzo-3,4-dihydrocarbazole-9-ethyl chloroformate (BCEOC) and its application for determination of amino acids from seeds and bryophyte plants using high-performance liquid chromatography with fluorescence detection and identification with electrospray ionization mass spectrometry

A pre-column derivatization method for the sensitive determination of amino acids and peptides using the tagging reagent 1,2-benzo-3,4dihydrocarbazole-9-ethyl chloroformate (BCEOC) followed by high-performance liquid chromatography with fluorescence detection has been developed. Identification of derivatives was carried out by liquid chromatography/electrospray ionization mass spectrometry (LC/ESI-MS/MS). The chromophore of 2-(9-carbazole)-ethyl chloroformate (CEOC) reagent was replaced by 1,2-benzo-3,4-dihydrocarbazole functional group, which resulted in a sensitive fluorescence derivatizing reagent BCEOC. BCEOC can easily and quickly label peptides and amino acids. Derivatives are stable enough to be efficiently analyzed by high-performance liquid chromatography. The derivatives showed an intense protonated molecular ion corresponding m/z (M + H)(+) under electrospray ionization (ESI) positive-ion mode with an exception being Tyr detected at negative mode. The collision-induced dissociation of protonated molecular ion formed a product at m/z 246.2 corresponding to the cleavage of C-O bond of BCEOC molecule. Studies on derivatization demonstrate excellent derivative yields over the pH 9.0-10.0. Maximal yields close to 100% are observed with a 3-4-fold molar reagent excess. Derivatives exhibit strong fluorescence and extracted detzvatization solution with n-hexane/ethyl acetate (10:1, v/v) allows for the direct injection with no significant interference from the major fluorescent reagent degradation by-products, such as 1,2-benzo-3,4-dihydrocarbazole-9-ethanol (BDC-OH) (a major by-product), mono- 1,2-benzo-3,4-dihydrocarbazole-9-ethyl carbonate (BCEOC-OH) and bis-(1,2-benzo-3,4-dihydrocarbazole-9-ethyl) carbonate (BCEOC)(2). In addition, the detection responses for BCEOC derivatives are compared to those obtained with previously synthesized 2-(9-carbazole)-ethyl chloroformate (CEOC) in our laboratory. The ratios AC(BCEOC)/AC(CEOC) = 2.05-6.51 for fluorescence responses are observed (here, AC is relative fluorescence response). Separation of the derivatized peptides and amino acids had been optimized on Hypersil BDS C-18 column. Detection limits were calculated from 1.0 pmol injection at a signal-to-noise ratio of 3, and were 6.3 (Lys)-177.6 (His) fmol. The mean interday accuracy ranged from 92 to 106% for fluorescence detection with mean %CV < 7.5. The mean interday precision for all standards was < 10% of the expected concentration. Excellent linear responses were observed with coefficients of > 0.9999. Good compositional data could be obtained from the analysis of derivatized protein hydrolysates containing as little as 50.5 ng of sample. Therefore, the facile BCEOC derivatization coupled with mass spectrometry allowed the development of a highly sensitive and specific method for the quantitative analysis of trace levels of amino acids and peptides from biological and natural environmental samples. (c) 2005 Elsevier B.V. All rights reserved.

中国煤中22种环境敏感微量元素的地球化学研究

本论文按照统一的采样和统一的分析测试方法对全国煤中22种环境敏感微量元素及全硫含量进行了系统的研究。通过统计学的方法不仅给出了中国煤炭部分环境敏感微量元素的分布范围、算术均值、标准差、几何均值、几何偏差，中位数，而且首次给出了95％置信度下算术均值、几何均值以及元素含量分布的置信区间等，并与前人大量样品的统计结果进行比较。还通过统计分析了部分环境敏感微量元素在我国煤中的主要赋存状态，以及选煤对这部分微量元素的脱除机理和脱除效果等，得到以下几点认识： 1. 通过与前人大量样品统计所得到的结果进行比较，进一步证明了论文中使用的这批样品是中国煤炭平均化学成分的良好代表。本次所分析的23种元素中，As、Be、Co、Cr、Cu、Hg、Pb、Se、Th、Tl、U、F、S等13元素与前人数10年研究的统计结果在分布范围、均值含量等上非常一致，但本次的结果更为可信，更接近中国煤炭平均化学成分的真实状况。此外，本次对这B、Sn这2种元素的分析数据也是目前反映我国煤中分布最具有代表性的数据。 2. 根据样品的无偏性，对平均值的置信区间进行计算。首次给出了全国煤中各元素在95％置信度下的算术均值的置信区间、几何均值的置信区间以及元素含量分布的置信区间等。可以为后人研究各元素在绝大多数煤中的含量及均值情况时作为参考。同时统计分析表明，按照95％置信度计算，16元素的真实平均值在我们所得到的平均值±11％范围之内，最大偏差为硒，在±20％之间。 3. 平均值作为最常用的统计量之一，中国煤中不同元素的不同均值之间有一定的差异，反映了元素在煤中不同的分布状态。论文中通过对23种元素在全国煤中的5种不同的均值比较，一般元素的产量加权均值与总体样品均值之间都比较接近；绝大多数元素的储量加权均值比较低，这与西北、华北地区未开采利用的煤炭资源量大，煤质好有关。 4. 通过与Swaine（1990）给出世界煤中元素的分布范围进行比较，22种环境敏感微量元素在我国煤中的分布处于世界煤的有限范围之内。其中，Cr、Cu、Mn、Mo、Se、Sn、Th、Tl、U、V、F等微量元素在我国煤中的分布与世界煤比较接近，而As、B、Ba、Be、Cd、Co、Cl、Hg、Ni、Pb、Sb等微量元素在我国煤中较世界煤低很多。 5. 与世界主要煤炭资源大国和Swaine（1990）给出的世界煤元素均值含量的比较显示，大部分环境敏感微量元素在我国煤中的均值含量与世界主要煤炭资源大国煤中的均值含量也比较接近。其中，我国煤中B、Co、Cu、Hg、Pb、U等6种元素含量均值与美国煤比较接近，As、Cd、Sb、Tl等4种元素含量均值与澳大利亚煤比较接近，Ba、Cr、Mo、Ni、V等4种元素含量均值与前苏联煤比较接近，Be、Mn、Se、Th、F等5种元素含量均值与世界煤比较接近。 6. 随着煤炭变质程度的增高，各元素均值含量没有表现出明显规律性的增高或降低。但22种环境敏感微量元素在褐煤、弱粘煤、不粘煤、气煤等较低变质程度煤中的含量整体水平不高，绝大多数微量元素主要在中高变质程度煤中较为更为富集。不同成煤时期以及不同聚煤区煤中各种环境敏感微量元素不同的富集程度，从总体上反应了绝大部分环境敏感微量元素在华南煤中更为富集，而占全国储量3/4的华北和西北煤中的总体水平相对较低。 7. 通过对环境敏感微量元素与灰分及主要灰成分之间的关系进行分析，初步了解了它们在煤中的主要赋存状态。煤中绝大部分环境敏感微量元素还是具有非常明显的无机亲和性，在煤中主要以矿物无机形态存在。主要与粘土矿物、黄铁矿及硫化物相结合，而与碳酸盐矿物关系不大。 8. 脱除率的分析显示，15种元素的脱除率与灰分的脱除率之间具有显著的正相关性，说明煤中绝大部分环境敏感微量元素主要以无机形态存在，因此提高原煤入洗率，降低原煤灰分的同时也可以在很大程度上降低环境敏感微量元素的燃煤排放。 9. 部分环境敏感元素的脱除率受到其在煤中的赋存状态、矿物形态、煤级以及选煤厂洗选工艺等诸多因素的影响，在不同样品中脱除率的差异较大。某些样品中微量元素的脱除率较高，最高脱除率可达到70％以上。从平均脱除率来看，灰分、硫分及绝大多数环境敏感微量元素处于30％－70％之间，只有少数几个元素不到20％。