IN-SITU SCANNING-TUNNELING-MICROSCOPY IMAGE OF A HIGHLY ORIENTED PYROLYTIC-GRAPHITE ELECTRODE MODIFIED WITH POTASSIUM BIS(11-MOLYBDOSILICATO) DYSPROSATE(III) IN SODIUM-SULFATE SOLUTION

The variation in molecule adsorption mode on pretreated highly oriented pyrolytic graphite electrodes, modified with the title complex K10H3[Dy(SiMo11O39)(2)] by cyclic voltammetry in the title complex solution, was observed in situ by electrochemical scanning tunnelling microscopy (ECSTM) with molecular resolution in sodium sulphate solution. According to the ECSTM images and the known molecular structure we conclude that the adsorption mode of the title complex modified electrode changed during potential cycling from ''vertical'' to ''inclined'' and then ''horizontal'' or ''flat'' mode, i.e. the title complex adsorbed on the surface of electrode by one ligand of the complex at first, then began to incline and was finally adsorbed by two ligands of the complex. This result indicates that the adsorption mode on the modified electrode surface changed during potential cycling in the sulphate solution and a much more stable molecular layer was formed. The change in adlattice of adsorbates on the modified electrode surface from hexagonal to rectangular was also observed by ECSTM. A plausible model was given to explain this process.

INVESTIGATIONS OF HYDROLYSIS KINETICS OF ATROPINE SULFATE BY ELECTROANALYSIS AT THE WATER NITROBENZENE INTERFACE

The hydrolysis kinetics of atropine sulphate has been investigated by cyclic voltammetry at the water/nitrobenzene interface. The transfer process is diffusion controlled and the transfer species is a 1:1 proton-atropine complex. Two main factors, pH and temperature, which have notable effects on the hydrolysis rate, are illustrated. The most suitable pH for atropine to be preserved in aqueous solution and related parameters were estimated.

POLYANILINE CHEMICALLY MODIFIED ELECTRODE FOR DETECTION OF ANIONS IN FLOW-INJECTION ANALYSIS AND ION CHROMATOGRAPHY

An electrochemical detector based on a polyaniline conducting polymer chemically modified electrode (PAn CME) was developed for use in flow-injection analysis and ion chromatography. Iodide, bromide, thiocyanate and thiosulphate are detected by using ion chromatography with a PAn CME electrochemical detector. The detection limits are 1, 5, 10 and 10 mgl-1, respectively. The CME response for electroinactive anions varies selectively with the mobile phase composition in flow-injection analysis. By this approach, perchlorate, sulphate, nitrate, iodide, acetate and oxalate can be detected conveniently and reproducibly over a linear concentration range of at least 3 orders of magnitude. The electrode is stable for over 2 weeks with no evidence of chemical or mechanical deterioration.

A novel anti-tumor protein extracted from Meretrix meretrix Linnaeus induces cell death by increasing cell permeability and inhibiting tubulin polymerization

Discovery and development of new pharmaceuticals from marine organisms are attracting increasing interest. Several agents derived from marine organisms are under preclinical and clinical evaluation as potential anticancer drugs. We extracted and purified a novel anti-tumor protein from the coelomic fluid of Meretrix meretrix Linnaeus by ammonium sulphate fractionation, ion exchange and hydrophobic interaction chromatography. The molecular weight of the highly purified protein, designated MML, was 40 kDa as determined by SDS-PAGE analysis. MML exhibited significant cytotoxicity to several cancer cell types, including human hepatoma BEL-7402, human breast cancer MCF-7 and human colon cancer HCT116 cells. However, no inhibitory effect was found when treating murine normal fibroblasts NIH3T3 and benign human breast MCF-10A cells with MML. The cell death induced by MML was characterized by cell morphological changes. The induction of apoptosis of BEL-7402 cells by MML was weak by DNA ladder assay. The possible mechanisms of its anti-tumor effect might be the changes in cell membrane permeability and inhibition of tubulin polymerization. MML may be developed as a novel, highly selective and effective anti-cancer drug.

The preparation and antioxidant activity of glucosamine sulfate

Glucosamine sulfate was prepared from glucosamine hydrochloride that was produced by acidic hydrolysis of chitin by ion-exchange method. Optical rotation and elemental analysis characterized the degree of its purity. In addition, the antioxidant potency of chitosan derivative-glucosamine sulfate was investigated in various established in vitro systems, such as superoxide (O (2) (-) )/hydroxyl (center dot OH) radicals scavenging, reducing power, iron ion chelating. The following results are obtained: first, glucosamine sulfate had pronounced scavenging effect on superoxide radical. For example the O (2) (-) scavenging activity of glucosamine sulfate was 92.11% at 0.8 mg/mL. Second, the center dot OH scavenging activity of glucosamine sulfate was also strong, and was about 50% at 3.2 mg/mL. Third, the reducing power of glucosamine sulfate was more pronounced. The reducing power of glucosamine sulfate was 0.643 at 0.75 mg/mL. However, its potency for ferrous ion chelating was weak. Furthermore, except for ferrous ion chelating potency, the scavenging rate of radical and reducing power of glucosamine sulfate were concentration-dependent and increased with their increasing concentrations, but its ferrous ion chelating potency decreased with the increasing concentration. The multiple antioxidant activities of glucosamine sulfate were evidents of reducing power and superoxide/hydroxyl radicals scavenging ability. These in vitro results suggest the possibility that glucosamine sulfate could be used effectively as an ingredient in health or functional food, to alleviate oxidative stress.

Antioxidant activity of different sulfate content derivatives of polysaccharide extracted from Ulva pertusa (Chlorophyta) in vitro

Polysaccharide extracted from Ulva pertusa (Chlorophyta) is a group of sulfated heteropolysaccharide; for simplicity, the sulfated polysaccharide is referred to as ulvan in this paper. In this study, different sulfate content ulvans were prepared with sulfur trioxide/N,N-diinethylformamide (SO3-DMF) in formamide, and their antioxidant activities were investigated including scavenging activity of superoxide and hydroxyl radicals, reducing Power and metal chelating ability. As expected, we obtained several satisfying results, as follows: firstly, high sulfate content ulvans had more effective scavenging activity on hydroxyl radical than natural ulvan. Secondly, comparing with natural ulvan, high sulfate content ulvans exhibited stronger reducing power. Thirdly, HU4 (sulfate content, 30.8%) and HU5 (sulfate content, 32.8%) showed more pronounce chelating ability on ferrous ion at high concentration than other samples. (c) 2005 Elsevier B.V. All rights reserved.

Antioxidant activity of differently regioselective chitosan sulfates in vitro

Differently regioselective chitosan sulfates were prepared according to Hanno Baumann's methods. Their antioxidant potencies were investigated employing various established in vitro systems, such as 1,1-diphenyl-2-picrylhydrazyl (DPPH)/superoxide/hydroxyl radicals scavenging, reducing power, iron ion chelating and total antioxidant activity. All kinds of sulfated chitosans (HCTS, TSCTS, SCTS, TCTS) showed strong inhibitory activity toward superoxide radical by the PMS-NADH system compared to Vc. According to the above-mentioned order their IC50 were 0.012, 0.040, 0.015, 0.022mg/mL, respectively, however, scavenging activity of Vc on superoxide radical was 68.19% at 2.0mg/mL. Scavenging activity of superoxide radical was found to be in the order of HCTS > SCTS > TCTS > TSCTS > Vc. Furthermore, all kinds of sulfated chitosans exhibited strong concentration-dependent inhibition of deoxyribose oxidation. Except for HCTS, others had stronger scavenging activity on hydroxyl radical than Vc. Scavenging effect of TSCTS on 1, 1 -diphenyl-2-picrylhydrazy] radical was little lower than that of BHA, but better than that of others. All kinds of sulfated chitosans were efficient in the reducing power, especially TSCTS. TSCTS and TCTS showed considerable ferrous ion chelating potency. The data obtained in vitro models clearly establish the antioxidant potency of all kinds of sulfated chitosans. These in vitro results suggested the possibility that sulfated chitosans could be effectively employed as ingredient in health or functional food, to alleviate oxidative stress. However, comprehensive studies need to be conducted to ascertain the in vivo safety of sulfated chitosans in experimental animal models. (C) 2004 Elsevier Ltd. All rights reserved.

Relevance of molecular weight of chitosan and its derivatives and their antioxidant activities in vitro

The antioxidant potency of different molecular weight (DMW) chitosan and sulfated chitosan derivatives was investigated employing various established in vitro systems, such as superoxide (O-2(.-))/hydroxyl ((OH)-O-.) radicals scavenging, reducing power, iron ion chelating. As expected, we obtained several satisfying results, as follows: Firstly, low molecular weight chitosan had stronger scavenging effect on O-2(.-) and (OH)-O-. than high molecular weight chitosan. For example the O-2(.-) scavenging activity of low molecular weight chitosan (9 kDa) and high molecular weight chitosan (760 kDa) were 85.86 % and 35.50 % at 1.6 mg/mL, respectively. Secondly, comparing with DMW chitosan, DMW sulfated chitosans had the stronger inhibition effect on 0(2)(.-). At 0.05 mg/mL, the scavenging activity on O-2(.-) reached 86.26 %, for low molecular weight chitosan sulfate (9 kDa), but that of low molecular weight chitosan (9 kDa) was 85.86 % at 1.6 mg/mL. As concerning chitosan and sulfated chitosan of the same molecular weight, scavenging activities of sulfated chitosan on superoxide and hydroxyl radicals were more pronounced than that of chitosan. Thirdly, low molecular weight chitosan sulfate had more effective scavenging activity on 02 and (OH)-O-. than that of high molecular weight chitosan sulfate. Fourthly, DMW chitosans and sulfated chitosans were efficient in the reducing power, especially LCTS. Their orders were found to be LCTS > CTS4 > HCTS > CTS3 > CTS2 > CTS1 > CTS. Fifthly, CTS4 showed more considerable ferrous ion-chelating potency than others. Finally, the scavenging rate and reducing power of DMW chitosan and sulfated derivatives increased with their increasing concentration. Moreover, change of DMW sulfated chitosans was the most pronounced within the experimental concentration. However, chelating effect of DMW chitosans were not concentration dependent except for CTS4 and CTS1. (C) 2004 Elsevier Ltd. All rights reserved.

Relevance of molecular weight of chitosan-N-2-hydroxypropyl trimethyl ammonium chloride and their antioxidant activities

The antioxidant potency of high/low molecular weight quatemary chitosan derivatives was investigated employing various established systems in vitro, such as superoxide (O-2(center dot-)) and hydroxyl (center dot OH) radicals scavenging, reducing power and iron ion chelating. As expected, we obtained several satisfying results, as follow: firstly, low molecular weight quaternary chitosan had stronger scavenging effect on O-2(center dot-) and center dot OH than high molecular weight quaternary chitosan. Secondly, the reducing power of low molecular weight quaternary chitosan was more pronounced than that of high molecular weight quaternary chitosan. Thirdly, ferrous ion chelating potency were showed to increase first and decrease afterwards with increasing concentration for two kinds of quaternary chitosans, namely, they have not concentration-dependence. However, the scavenging rate and reducing power of high and low molecular weight quaternary chitosans increased with their increasing conc centrations, and hence were concentration-dependent. (c) 2007 Elsevier Masson SAS. All rights reserved.

The antioxidant activity of glucosamine hydrochloride in vitro

The antioxidant potency of chitin derivative-glucosamine hydrochloride was investigated employing various established in vitro systems. Such as superoxide (O-2(center dot-))/hydroxyl ((OH)-O-center dot)-radical scavenging, reducing power, and ferrous ion chelating potency. As expected, we obtained several satisfying results, its follows: first, glucosamine hydrochloride had pronounced scavenging effect on superoxide radical. For example, the O-2(center dot-) scavenging activity of glucosamine hydrochloride was 83.74 parts per thousand at 0.8 mg/mL. Second, the (OH)-O-center dot scavenging activity of glucosamine hydrochloride was also strong and was about 54.89% at 3.2 mg/mL. Third, the reducing power of glucosamine hydrochloride was more pronounced. The reducing power of glucosamine hydrochloride was 0.632 at 0.75 mg/mL. However, ferrous ion-chelating potency was soft. Furthermore, ferrous ion-chelating potency, the scavenging rate of radical, and the reducing power of glucosamine hydrochloride increased with their increasing concentration, and they were concentration dependent. The multiple antioxidant activity of glucosamine hydrochloride was evident as it showed considerable reducing power, superoxide/hydroxyl-radical scavenging ability. These in vitro results suggest the possibility that glucosamille hydrochloride could be effectively employed its an ingredient in health or functional food, to alleviate oxidative stress. (c) 2005 Elsevier Ltd. All rights reserved.

扬子地区上奥陶－下志留统黑色岩系形成机理

The black rock series of the Upper Ordovician - Lower Silurian in Yangtze area are important source rocks and have exceptional characteristics of sediment, biology, element geochemistry, carbon and oxygen isotope, organic geochemistry and etc. These characteristics are the reflection of important geology events. Due to scarce system research, many problems that relate to the development mechanism of source rocks are not solved. And this restricts the exploration of Oil and gas in South China. In this paper, author studied the palaeo-climate, palaeo-structure and palaeo-environment of the Upper Ordovician - Lower Silurian in Yangtze area by sedimentology, palaeobiology and geochemistry, especially the element geochemistry and isotope geochemistry. The environment model of source rocks is established and some conclusions are drawn. The Upper Ordovician - Lower Silurian sediment types in Yangtze area are mostly black shales, next, mudstone, shell limestone and siltystone. During the Late Ordovician and Earily Silurian periods, a series of big upheaval and depressed are distributed in Yangtze area, and the strata pattern of interphase upheaval and depressed led to Yangtze palaeosea isolated with outside sea. So the stagnant and anoxic environment that are the favorable factor of rich organic black shales sediment is formed in Yangtze area. That Chemical Index of Alteration (CIA) values of the lower Wufeng formation and Longmaxi formation exhibits moderate chemistry weathering suggests they were deposited under the circumstances of the warm and humid climate. However, the large difference of the CIA values of N.extraordinarius-N.ojsuensis biozone suggests that climate is changeful. Therefore, there were two different kinds of climates in the course of the deposition of the Wufeng formation and Longmaxi formation. During the Late Ordovician - Earily Silurian periods, in Yangtze palaeosea, the surface water which is full of rich nutriment and abundant bacterium - algae has high palaeo-productivity that is obvious difference in the different space – time. The content of sulphate changes gradually from the surface water columns to the deep water columns. That is, salinity in the surface water columns is serious low and the salinity in deep water columns is normal. Salinity delamination is favor of the forming of deep anoxic environment. During Wufeng period, the oxidated and low sulfate environment exists in the upper Yangtze palaeosea, while the anoxic and normal salinity environment occurs in the lower Yangtze palaeosea. During the Late Wufeng and Guanyinqiao periods, the steady anoxic environment is replaced by oxidated environment. During the Longmaxi period, layered and anoxic environment recur. In Yangtze area, studies of δ13C of sedimentary organic carbon show a positive δ13C excursion up to 4‰ in the Guanyinqiao stage and then, acute negative excursion in the earily Longmaxi stage. These organic carbon isotopes curve are not only efficient measure of carving up strata borderline, but also reflected the change of originality productivity. These organic carbon isotopes curves showed the process of the enhanced embedding of the global organic carbon. Anoxic event is the main factor of increasing organic carbon embedding speed. And the reduced organic carbon embedding in Hirnantian stage is due to the water column with abundant oxygen. The δ34S values are gradually positive excursion from P.pacificus biozone to N.extraordinarius biozone, and reach the maximum in the Upper Hirnantian stage. Then, the δ34S values are negative excursion. The excursions of δ13C and δ34S reflect the acute change of environment. The formation of source rocks is largely dependent on the nature of organisms from which kerogen is derived and the preservation conditions of organic matter, which are fundamentally dependent on a favourable combination of various elements in which organisms live and are subsequently buried. These elements include palaeoclimate, palaeostructure and palaeoenvironmental conditions. Based on above mentioned circumstance, the coupling connection of source rock and the palaeoclimate, and of palaeostructure and palaeoenvironmental conditions are confirmed, and the “anoxic-marginal depression-photosynthesis” environemental model is established. It is indicated that anoxic played important role in production of organic matter. The produced organic matter was accumulated in marginal depression of the Yangtze area. The photosynthesis is favor of the high productivity. Source rocks have a good perspective, like that of “hot shale” deposited in North Africa.

富硫流体的成因与硫酸盐还原作用研究

Origins of H_2S, thiols, thiophenes in natural gases and sulphur-enriched oils are complicated and thus some debates exist on them. The post-doctoral research is based upon oil- and gas-field data. Cases for study include Triassic Jianglingjiang Formation natural gases, Wolonghe Field, Sichuan Basin, Paleozoic oils and bitumen, Central Tarim, gases reserviored nearby Carboniferious - Ordovician unconformity, Hetianhe Field, Tarim Basin and sulphur-enriched oils in Tertiary reserviors in Jinxian Sag, Bohai Bay Basin. We have carried out analyses on the oils and gases for chemistry, δ~(13)C, δ~(34)S, and molecular composition of biomarkers, analyzed authigenetic pyrite forδ~(34)S, formation water for chemistry and δD and δ~(18)O along with petroleum system and burial history analyses, The aims are to assess the origins of the H2S and authigenetic pyrite, to discuss the possibility of reduced sulphur incorporation into hydrocarbons and to determine the mechanisms of hydrocarbon secondary alteration in the above four cases by comparison. The research shows that the reduced sulphur in the four cases is the result of thermochemical and biological sulphate reduction., TSR and BSR, respectively. No evidence indicates an origin of decomposition of organic matter or mantle - derived H2S in the cases. Elevated H_2S contents (up to 32%) in the Triassic Jialingjiang Formation are considered to result from TSR while relatively low H_2S (up to 2000ppm) in the Hetianhe Field resulted from BSR. However, it is not the case for the Central Tarim where relatively low H2S but abundant authigenetic pyrite occurr. Part of the H_2S in the Central Tarim reservoirs has reacted with iron released from clay minerals to precipitate pyrite. Thus, reduced sulphur δ~(34)S and reservoir temperatures rather than the H2S amount are reliable parameters to distinguish between TSR and BSR. TSR in Sichuan Basin Triassic Jialingjiang Formation and Central Tarim Paleozoic reservoirs are showed to take place at more than 125℃. the H2S and authigenetic pyrite have δ~(34)S close to parent anhydrite. In contrast, BSR in the reservoirs near the Carboniferous - Ordovician unconformity in the Hetianhe Field and in the Tertiary in the Jinxian Sag took place at temperatures less than 80℃with sulphide δ~(34)S as light as -24.9‰ and -12.5‰, anhydrite δ~(34)S as heavy as +26‰and +3 5-+40‰, respectively. Chemistry and isotopic composition of the natural gases change as the result of sulphate reduction. It has been observed that relative composition of light hydrocarbon gases is changed along with a rise in H_2S and CO_2. TSR in the Triassic Jialingjiang Formation and BSR in the Hetianhe Field result in a greater degree of preferential depletion of methane than larger molecular hydrocarbon gases. As TSR or BSR proceeds, hydrocarbon gases evolved to heavier carbon isotope as the result of kinetic isotopic fractionation, i.e., selective anaerobic oxidation of ~(12)C. Using the model of residual methane (Whiticar, 1999) to describe the relationship among the proportion of methane oxidation, isotopic shift and fraction factor, about 30% methane is calculated to have been oxidized during BSR in the western part of the Hetianhe Field. From the above, it can be concluded that in the area where H_2S is abundant, empiricalδ~(13)C -Ro relationships do not work. Sulphate reduction results in a rise in sulphur content, gravity and viscosity of an oil as well as changes in δ~(13)C and δ~(34)S. On special conditions, the reduced sulphur from sulphates might be incorporated into oils, i.e., the increasing sulphur is derived from secondarily reduced sulphur. A positive correlative relationship exists between sulphur content and δ~(34)S in the oils in Paleozoic reservoirs in Central Tarim, indicating that enhanced sulphur is ~(34)S-enriched, originated from TSR. The Jinxian oil with the highest sulphur content has the lightest δ~(34)S, suggesting part of the sulphur in the oil is ~(34)S-depleted, originated from BSR. In the Jinxian oil with increasing sulphur content, asphaltenes shows higher content and more negative δ~(13)C, and saturates shows evidence of biodegradetion and a decreasing content and a positive δ~(13)C shift. Thus, asphaltenes have δ~(13)C values closer to saturates. All the above indicate that the reduced sulphur has been incorporated into biodegradated saturates to generate new asphaltenes with relatively light δ~(13)C of saturates. Thiols and thiophenes in natural gases in the Triassic Jialingjiang Formation may result from reaction of H_2S with hydrocarbon. In the Jialingjiang Formation hydrocarbon gases are dominated by methane thus have a high dryness coefficient and thiols are showed to be positively related to H_2S content, suggesting that the thiols may result from H_2S reaction with short chain hydrocarbons. In contrast, high thiophenes occur in wet gases in Jurassic reservoirs with their source rock from sulphur - depleted type I kerogen, indicating that thiophenes may be a product of reaction of H2S with longer chain hydrocarbons.

湖泊生态系统铁同位素与硫同位素地球化学研究--以红枫湖、阿哈湖为例

湖泊生态系统是陆地水体生态系统的重要组成部分。随着社会经济的不断发展，各种人为因素对湖泊生态系统的影响日益突出，打破了其自然演变规律，诸如 “二次污染”、水体富营养化、重金属污染等环境问题接踵而来。而铁是水生生态系统初级生产力所必需的重要微量营养元素之一，在一定的条件下可以控制和影响浮游藻类的生长速度和种类；而且，铁的氧化还原敏感性很强，其价态的改变往往会影响其它相关重金属的迁移和转化。因此，湖泊生态系统中铁的生物地球化学循环研究具有非常重要的意义。近年来的研究显示，铁同位素分析技术可以用于各种生物作用和非生物作用过程的研究，在海洋和河流生态系统中已有广泛的应用，而对湖泊生态系统的研究则鲜见报导。乌江流域中等富营养化的湖泊――红枫湖和贵阳西南郊矿化程度较高的湖泊――阿哈湖是研究湖泊生态系统中铁生物地球化学循环的理想场所。本文选取这两个性质不同的湖泊为研究对象，运用硫同位素、铁同位素及重金属和营养盐等地球化学方法手段，对两湖流域内硫酸盐的来源、硫同位素的季节和剖面变化特征、铁的来源及铁同位素组成的季节和剖面变化特征及其控制和影响因素等进行了研究和探讨，进一步完善了铁同位素分馏机理，为深化理解和研究湖泊生态系统中铁和硫的生物地球化学循环提供一定的科学依据。论文所获的主要认识总结如下： 两湖流域内湖水与河水的硫酸盐硫同位素地球化学 （1）阿哈湖流域和红枫湖流域水体的硫酸盐浓度和δ34S值均有较宽的分布范围。各入湖支流中，受煤矿废水或煤矸石淋溶液污染的河水的δ34S值相对较低（-8.10‰～-14.92‰），而受生活污水影响严重的河水则具有相对较高的δ34S值（-5.68‰～+0.88‰）。相比而言，阿哈湖流域水体纳入了大量的煤矿废水和煤矸石淋溶液，硫污染程度较红枫湖流域更为严重。因此，阿哈湖湖水具有相对较高的硫酸根浓度（平均为2.30 mmol.L-1）和相对较低的δ34S值（平均为-8.10‰），而红枫湖则具有相对较低的硫酸根浓度（平均为0.96 mmol.L-1）和相对较高的δ34S值（平均为-6.80‰）。 （2）阿哈湖湖水中的硫酸盐主要受煤矿废水、煤矸石淋溶液以及雨水等的控制；红枫湖湖水的硫酸盐主要来源于煤中黄铁矿的氧化和雨水输入，土壤硫化物的氧化和蒸发岩的溶解对湖水硫酸盐硫同位素组成的贡献较小。相比之下，雨水对红枫湖湖水硫同位素的影响更为明显。 （3）红枫湖和阿哈湖湖水的硫酸盐的δ34S值均具有明显的剖面变化特征，而且两湖的变化趋势相似，总体表现为，夏秋季节表层湖水和底层湖水的δ34S值相对较高，而冬春季节湖水剖面上下几乎没有变化。湖水硫酸盐浓度也呈现类似的变化特征，这主要与季节性厌氧湖泊夏季分层冬季混和的典型特点有关。夏季湖水分层期间，大量降雨在湖泊表层的滞留使得δ34S值升高而硫酸盐浓度降低，湖泊底部水层中硫酸盐细菌的还原作用使得底层湖水的硫酸盐浓度降低，而δ34S值升高。 两湖流域内铁同位素地球化学 （1）阿哈湖流域各类样品的δ56Fe值分布在-2.03‰～+0.12‰之间，分布范围较宽。其中湖水悬浮颗粒物的δ56Fe值在-1.36‰～-0.03‰之间，整体相对偏负。湖周各支流河水悬浮颗粒物的δ56Fe值在-0.88‰～+0.07‰之间，也相对富集轻的铁同位素；湖底沉积物和孔隙水的δ56Fe值的分布范围分别为-1.75‰～-0.59‰和-2.03‰～+0.12‰；大气颗粒物和浮游藻类的δ56Fe值分别为+0.06±0.02‰和+0.08‰。与阿哈湖相比，红枫湖流域各类样品的δ56Fe值的分布范围相对较窄，在-0.92‰～+0.36‰之间。湖水悬浮颗粒物的δ56Fe值在-0.85‰～+0.14‰之间，河水悬浮颗粒物的铁同位素组成变化范围为-0.89‰～+0.10‰，二者的变化范围相似。红枫湖沉积物的δ56Fe值在-0.18‰～+0.08‰之间，明显比阿哈湖沉积物的铁同位素组成偏正；而对应孔隙水的铁同位素组成的变化范围为-0.59‰～-0.24‰，均要比对应沉积物的铁同位素值要低。藻类和鲫鱼鱼肉的δ56Fe值分别为+0.36‰和-0.92‰。 （2）通过对两湖研究区湖水悬浮颗粒物与各输入端员环境样品的铁同位素值的研究表明，湖水悬浮颗粒物的δ56Fe值不仅受各输入端员的控制和影响，湖泊内部相关的生物地球化学过程也对湖水悬浮颗粒物的铁同位素组成变化产生了重要影响。两湖研究区内湖水悬浮颗粒物的铁同位素组成均存在季节变化特征，但受湖泊自身特点的影响，主要控制因素方面存在一定差异。夏季阿哈湖湖水悬浮颗粒物的铁同位素值变幅较大，其变化主要表现在表层和底层。表层因受陆源输入的有机结合态铁的影响而具有较负的δ56Fe值，而大气沉降颗粒物和湖泊表层的浮游藻类的影响并不显著。夏季湖水分层期间，“Ferrous Wheel”铁循环对于界面附近铁同位素的重分配起到了主要的控制和影响作用，湖水悬浮颗粒物的铁同位素值在氧化－还原界面附近达到了极负值。水－沉积物界面附近滞水层中亚铁类硫化物的生成可能也是水－沉积物界面附近水层内颗粒物的δ56Fe值偏负的原因之一。而冬季湖水混和时期，阿哈湖湖水剖面悬浮颗粒物的δ56Fe值的变幅明显减小。与阿哈湖不同，藻类的吸附作用可能在夏季红枫湖上层水体中占有主导地位，其湖水悬浮颗粒物的铁同位素组成随叶绿素水平的降低而逐渐降低。下层湖水悬浮颗粒物的铁同位素组成变化也受“Ferrous Wheel”铁循环的影响，在红枫湖后五剖面 20m 处达到-0.18‰，大坝剖面底层约为-0.46‰，其变幅没有阿哈湖悬浮颗粒物的δ56Fe值大，可能是受到了湖水中大量有机物质的影响。冬季红枫湖后五剖面的变化趋势与夏季相似，上层和下层水体悬浮颗粒物分别受不同影响因素的控制。上层水体悬浮颗粒物的铁同位素变化不明显，与Fe、Al、Mn、Zn、Co等元素的含量呈现良好的正相关关系；而底层水体悬浮颗粒物的δ56Fe值变幅比夏季要大，HW采样点20m处可达-0.85‰，与Fe、Al、Zn、Co等呈现良好的负相关关系，具体影响因素还有待于进一步研究。

Relacje między zgrupowaniami ameb skorupkowych, roślinnością i parametrami siedliskowymi torfowisk minerotroficznych Wielkopolski

Wydział Biologii: Instytut Biologii Środowiska/Zakład Hydrobiologii

Capillary electrophoresis with boron doped diamond electrode for amperometric detection of low molecular weight biological substrate

The research work in this thesis included the sensitive and selective separation of biological substance by capillary electrophoresis with a boron doped diamond electrode for amperometric detection. Chapter 1 introduced the capillary electrophoresis and electrochemical detection. It included the different modes of capillary electrophoresis, polyelectrolyte multilayers coating for open tubular capillary electrochromatography, different modes of electrochemical detection and carbon based electrodes. Chapter 2 showed the synthesized and electropolymerized N-acetyltyramine with a negatively charged sulfobutylether-β-cyclodextrin on a boron doped diamond (BDD) electrode followed by the electropolymerzation of pyrrole to form a stable and permselective film for selective dopamine detection. For comparison, a glassy carbon (GC) electrode with a combined electropolymerized permselective film of polytyramine and polypyrrole-1-propionic acid was used for selective detection of dopamine. The detection limit of dopamine was improved from 100 nM at a GC electrode to 5 nM at a BDD electrode. Chapter 3 showed field-amplified sample stacking using a fused silica capillary coated with gold nanoparticles embedded in poly(diallyldimethylammonium) chloride, which has been investigated for the electrophoretic separation of indoxyl sulphate, homovanillic acid and vanillylmandelic acid. The detection limit of the three analytes obtained by using a boron doped diamond electrode was around 75 nM, which was significantly below their normal physiological levels in biological fluids. This combined separation and detection scheme was applied to the direct analysis of these analytes and other interfereing chemicals including uric and ascorbic acids in urine samples without off-line sample treatment or preconcentration. Chapter 4 showed the selective detection of Pseudomonas Quinolone Signal, PQS for quorum sensing from its precursor HHQ, using a simply boron doped diamond electrode. Furthermore, by combining poly(diallyldimethylammonium) chloride modified fused silica capillary with a BDD electrode for amperometric detection, PQS was separated from HHQ and other analogues. The detection limit of PQS was as low as 65 nM. Different P. aeruginosa mutant strains were studied. Chapter 5 showed the separation of aminothiols by layer-by-layer coating of silica capillary with a boron doped diamond electrode. The capillary was layer-by-layer coated with the polycation poly(diallyldimethylammonium) chloride and negatively charged silica nanoparticles. All the aminothiols was separated and detected using a BDD electrode in an acidic electrolyte. It was a novel scheme for the separation and detection of glutathione reduced and oxidized forms, which is important for estimated overstressed level in the human system.