三峡库区水体溶解有机质的荧光光谱特性

利用荧光发射和三维荧光光谱(EEM)研究了三峡库区(TGRA)长江干流及嘉陵江、乌江两支流水体溶解有机质(DOM)的荧光特性.结合采样段面溶解有机碳(DOC)、氧化还原电位(ORP)、pH等参数,考察了干流、两支流及其汇合后各水体DOM的荧光指数f450/500和类腐殖酸与类富里酸强度比值rC/D变化,分析了类腐殖酸、类富里酸及类蛋白质在库区支流与干流、上游与下游水体的来源、组成、分布及环境行为.实验表明: 干流水体中DOM以类富里酸、类蛋白质荧光有机质为主;嘉陵江水体DOM以类蛋白质为主,富里酸次之; 在朝天门与长江汇合后,类蛋白峰强减弱而类腐殖酸有一定增加;乌江以类富里酸为主,汇合干流后,富里酸和类蛋白质峰增强;库区上游水体DOM主要受嘉陵江影响;干流DOM受陆源性影响.初步揭示了水体DOM的EEM特性与库区水质参数的相关性,为水体监测与分析提供参考.     

基于超高分辨质谱的溶解性有机质分子转化机理分析

本研究对比分析了不同处理工艺对制药废水中溶解性有机质(DOM)的降解, 通过三维荧光图谱(EEM)、总有机碳(TOC)、zeta电位以及动态光散射技术进行表征分析, 并利用超高分辨质谱进一步探究了过硫酸钾(PS), 碳纳米管(CNTs), CNTs/PS工艺诱导的DOM分子转化机制. 结果表明, PS通过静电聚合作用和氧化作用对DOM中的缩合芳香类化合物(76%)和蛋白质/多肽类(65%)去除较大, CNTs通过吸附作用对不饱和水平较低的含氧化合物(木质素类、蛋白质/多肽类和氨基糖类(90%))的去除最为显著, 而CNTs/PS则是通过吸附作用、电子转移以及单线态氧(¹O₂)的生成以实现不同组分的DOM的高效去除. 化学参数定量分布以及线性拟合分析表明, PS和CNTs/PS体系对于DOM分子的化学参数分布影响较小, 而CNTs的吸附作用会导致残留分子的平均氧碳比(O/C)、芳香指数(AI_mod)、等价双键(DBE)和碳的名义氧化态(NOSC)数值增加, 且氧原子对DBE的贡献作用增大. 本研究结果为进一步理解DOM在水环境中的去除和分子转化提供了理论依据.     

不同分子尺寸溶解性有机物的光解行为研究

研究了三个分子量区间(0.45μm~100kDa,100~5kDa和5kDa)的溶解性有机物(DOM)在不同光源辐照下的光解行为。溶解有机碳(DOC)和UV254的测试结果表明,光解可以有效地减少所有分子量区间的DOM总量,而且UVC光源的存在可以进一步促进DOM的降解。三维荧光光谱测定结合平行因子分析,识别出3个腐殖质类荧光组分(C1:UVA+UVC,C2:UVA+UVB,C3:UVC)。在光解过程中,较大分子腐殖质类(5kDa)的荧光强度相对较稳定,甚至增强;而小分子腐殖质类(5kDa)的荧光组分C1和C2具有显著的光解行为,UVC的存在可以促进两种荧光组分的光解。所有分子量区间的C3组分都发生了光生成现象。     

堆肥过程不同分子量水溶性有机物电子转移能力的演变及影响因素

利用超滤技术、电化学方法和光谱技术, 以堆肥水溶性有机物的不同分子量(MW)组分为研究对象, 分析在堆肥过程中不同分子量水溶性有机物(DOM)的组成特征、结构演变和电子转移能力变化的影响因素.结果表明, 类蛋白物质主要存在于堆肥前期的DOM(MW<1 kDa)中, 随着堆肥的进行, 类蛋白物质不断降解, 类富里酸物质持续合成, 堆肥后期类蛋白物质被完全降解, 类富里酸物质成为DOM(MW<1 kDa)主要的荧光组分.类腐殖物质是DOM(MW=1～3 kDa)、DOM(MW=3～5 kDa)和DOM(MW>5 kDa)的主要荧光组分, 堆肥过程中类腐殖质物质在3种不同分子量组分的变化各不相同, 但是堆肥后期类腐殖质物质在3个不同分子量组分的含量均高于堆肥初期. 堆肥过程中DOM(MW<1 kDa)的电子供给能力(EDC)呈降低趋势, 而电子接受能力(EAC)呈升高趋势; DOM(MW>5 kDa)的EDC在堆肥过程中呈上升趋势, 而EAC则无明显的变化规律.DOM(MW=1～3 kDa)和DOM(MW=3～5 kDa)的EDC和EAC在整个堆肥过程无明显变化规律.不同分子量组分堆肥DOM 的EAC受控于堆肥过程木质素降解产物的含量, 而其EDC变化与荧光参数和紫外参数无明显关系.     

生物炭和沼液DOM与Pb(Ⅱ)络合的二维相关光谱特性

本文采用荧光猝灭滴定结合二维相关光谱和移动窗口二维相关光谱比较分析生物炭和沼液中溶解性有机物(DOM)与重金属Pb(Ⅱ)的络合特性。研究结果表明,生物炭DOM主要以类腐殖酸为主,而沼液DOM以类蛋白物质为主;生物炭DOM在387nm处的类腐殖酸组分能够优先与Pb(Ⅱ)络合,其次是467nm和538nm处的类腐殖酸,最后是类蛋白荧光物质;沼液DOM组分与Pb(Ⅱ)络合的优先次序依次为282→422→409→366→328→376nm。研究结果也表明,对二维相关光谱同步和异步的1/n次转换光谱能够清晰地识别出被掩盖的荧光峰信息,且能够保留原来光谱信息的络合次序。生物炭DOM与Pb(Ⅱ)的络合物在90～160μM·L^-1之间分别在309nm、335nm、387nm、432nm和467nm发生构象变化。沼液DOM与Pb(Ⅱ)的络合物分别在282nm和328nm处发生了构象变化,构象变化的跃迁点在78μM·L^-1。生物炭DOM与Pb(Ⅱ)的lgK值在4.63～5.33之间,类富里酸与Pb(Ⅱ)的lgK值明显要低于类腐殖酸。沼液DOM与Pb(Ⅱ)的lgK...     

三维荧光光谱研究垃圾渗滤液水溶性有机物与汞相互作用

为了研究垃圾填埋过程中渗滤液水溶性有机物(DOM)对重金属配位能力的影响,采用三维荧光光谱、共振瑞利散射、荧光猝灭滴定技术及非线性回归拟合分析,研究了不同填埋年限渗滤液DOM与Hg(II)的相互作用过程.结果表明: Hg(II)与DOM中不同荧光基团配位比接近1: 1,配位过程中没有生成沉淀;不同填埋年限渗滤液DOM中类蛋白物质和类富里酸物质与Hg(II)配位的条件稳定常数分别为4.30～5.70和4.35～4.98;参与配位的荧光基团分别为54.1%～92.3%和35.8%～60.1%.随着填埋年限的增加,类富里酸物质对Hg(II)的配位能力降低,但参与配位的荧光基团的比例增加.渗滤液DOM-Hg(II)配位过程受介质pH值的影响,在酸性和碱性范围内尤为明显.     

液液萃取-荧光分析法测定注射剂中盐酸利多卡因的含量

基于盐酸利多卡因在pH=4.0条件下的水解产物2,6-二甲基苯胺(DMA)的强荧光性质,建立了一种测定盐酸利多卡因药物含量的新方法。考察了溶剂对DMA光谱性质的影响,结果表明随着溶剂极性的增强,其荧光光谱和吸收光谱强度均下降。在乙醚溶剂中,DMA在305nm激发波长下于324nm处有最强的荧光发射峰,明显区别于利多卡因水溶液的荧光发射峰。DMA的浓度与其荧光峰强度在一定范围内呈良好的线性关系,相关系数r=0.9975,检测限(3s/K)为9.72×10-8 mol/L。将该方法用于注射液中盐酸利多卡因含量的测定,与高效液相色谱法对照,结果吻合。     

HPSEC-UV-ICP-MS法测定天然水体中元素在不同分子量段DOM中的分布

溶解有机物(DOM)对痕量金属的形态、生物可利用性及其最终归属都有着很大的影响. 由于腐殖质(HS)是DOM的最大组成部分, 占溶解有机碳比重的40％-70％, 而HS是由芳香族、酚族、 醌族和杂环的结构单元无规则缩合连接成的大分子. 这种多官能团的结构使得HS与痕量金属有着很强的络合能力, 从而增加了天然水体中的金属浓度. 本文利用此技术首次获得了11种元素在海水水体中DOM上不同分子量的天然分布, 探讨了DOM对痕量金属在天然水体中的形态及迁移的影响.     

溶解有机质对光照自然水体生物膜体系中H2O2生成的影响

通过模拟实验研究了生物膜胞外聚合物(EPS)和乙二胺四乙酸(EDTA) 2种典型溶解有机质(DOM)成分对自然水体生物膜体系中过氧化氢(H₂O₂)生成特征的影响, 并研究了体系初始pH值、 DOM浓度、 溶解氧(DO)等因素的影响. 结果表明, DOM的存在对自然水体生物膜体系中H₂O₂的生成有明显影响. 光照能促使EPS产生H₂O₂, 而EPS的存在对生物膜产生H₂O₂的直接影响不显著, EPS与生物膜共存体系中的H₂O₂由二者共同产生; EDTA本身不产生H₂O₂, 且对H₂O₂分解影响很小, 但会显著抑制生物膜产生H₂O₂, 且浓度越高抑制作用越明显. 体系pH值、 DOM浓度和DO均能不同程度影响EPS产生H₂O₂及EDTA抑制生物膜产生H₂O₂的作用.     

基于半花菁结构的酸性pH荧光探针

基于半花菁结构,设计合成了一种酸性pH荧光探针MCPA,并对其进行了结构表征及光谱性能研究。结果表明,探针MCPA的pK_a为4.23,能快速响应溶液pH的变化。当pH 4.23时,MCPA溶液在605 nm处有强吸收峰,642 nm处有强荧光发射峰(最大激发波长为605 nm)。而当溶液pH 4.23时,MCPA溶液在605 nm处的特征吸收峰强度逐渐降低,并在460 nm处出现新的吸收峰,且溶液的荧光强度急剧降低直至无荧光。进一步研究表明,探针MCPA在642 nm处的荧光强度与溶液pH呈现良好的线性关系,线性范围为pH 3.4～5.0,可用于检测酸性溶液中pH的变化。探针MCPA在水溶液中非常稳定,对常见干扰组分具有较好的抗干扰能力。     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.     

Synthesis of pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles by Curtius reaction in Morita-Baylis-Hillman derivatives

Synthesis of substituted pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles from the Morita-Baylis-Hillman derivatives of acrylates via saponification followed by Curtius reaction is described.     

正丁胺对激光染料荧光谱影响的研究

用正丁胺作为碳源,采用射频辉光放电制备碳膜,选用激光染料R6G和聚乙二醇混合液作为蒸气源,采用单源热蒸发,在蒸发室与染料同时沉积得到混合膜,用拉曼光谱和红外光谱分析了碳膜的结构和键合方式,分析表明:碳膜中存在胺基团和氢原子.混合膜的荧光谱测量结果表明,认为正丁胺对染料荧光谱的影响是因为胺基和氢原子的存在.     

Cu0-catalysed 1,3-dipolar cycloadditions of α-amino acid derived N,N-cyclic azomethine imines to ynones

A series of 20 CuAIAC reactions between eight 4-acylamino substituted pyrazolidine-3-one-1-azomethine imines and four terminal ynones were performed using Cu⁰ as catalyst. The corresponding fluorescent cycloadducts were obtained in very high yields upon simple workup. Thus, Cu-metal turned out to be a better catalyst than Cu^I in terms of yield and ease of isolation. Availability of azomethine imines, mild reaction conditions, and simple workup enable a “click” access to libraries of densely substituted 2,3-dihydro-1H,5H-pyrazolo[1,2-a]pyrazol-1-ones. Reactivity of differently substituted dipoles was evaluated experimentally and by quantum chemical methods (DFT).     

Synthesis and antioxidative/anti-inflammatory activity of novel fullerene–polyamine conjugates

(E)-4-(Fullerenopyrrolidin-1-yl)-3-methylbut-2-enoic acid and its corresponding succinimidyl ester, readily obtained through Prato-type modification of C₆₀, were used for the selective N-acylation of polyamines. The thus obtained conjugates were evaluated for their antioxidative and anti-inflammatory activity and their cytotoxicity was determined. Members of this family of compounds showed interesting anti-lipid peroxidation, anti-lipoxygenase and anti-inflammatory activity and comparable cytocompatibility to spermidine.