海洋生物中硒的催化动力学光度测定与形态分布研究

建立了一种测定海洋生物中不同形态硒的催化动力学光度法。在pH=3的Clark—Lubs缓冲介质中，硒(Ⅳ)能催化溴酸钾氧化甲基紫的褪色反应，硒(Ⅳ)含量在0．14～8μg／L范围内与褪色反应速率成正比，生物样品经HNO3-HClO4消化后直接测定硒(Ⅳ)和有机硒含量，再经盐酸还原后测定总硒含量，两者差减得硒(Ⅵ)含量。结合MIBK(甲基异丁基酮)萃取分离干扰组分，该方法具有良好的选择性和准确度，用于海洋生物材料中不同形态硒的测定，操作简便快速，结果令人满意。对几种海藻和双壳贝类样品中硒的形态分析结果表明，在海洋生物中，硒主要以有机硒和硒(Ⅳ)的形式存在于难溶性的大分子蛋白质中，硒(Ⅵ)的含量普遍较低，且存在显著的种间差异。     

Geochemical Evaluation of Soil Quality in Menyuan County of Qinghai Province北大核心CSCD

青海省门源县内林草地面积大于44万公顷,耕地仅不到4.2万公顷,林草地资源丰富。2016年在门源县地区开展了1：25万土地质量地球化学评价工作,是青海省首次在大面积林草地区开展1：25万土地质量地球化学调查工作,具有较好的示范作用。通过评价土壤养分、土壤环境等级划分了土壤质量地球化学综合等级,结果表明：门源县土壤质量一等优质土壤占比92.4%,二等良好土壤占0.8%,三等中等土壤占5.6%,四等差等土壤占0.9%,五等劣等土壤占0.3%。通过项目实施可服务门源县土地资源管理,为门源县土地规划利用、农业种植结构调整及生态环境治理等提供依据,助力门源县绿色有机农畜产品输出地建设。     

元素俘获能谱在深层致密储层评价中的应用:以松科2井为例

松辽盆地沙河子组存在多段气测异常,显示了该地层具有致密气勘探潜力,但研究区深层致密储层非均质性强、厚度薄、互层发育且类型多样。在松科2井常规测井曲线分析基础上,利用元素俘获能谱精细反演矿物组分含量,对地层岩性进行准确识别,并建立了元素交汇图识别出5种类型储层。结合岩石物理实验资料,得到地层的变骨架孔隙度、脆性指数、有机碳含量等储层评价参数,依据气测资料及综合评价指数将储层分为三大类。研究结果表明:沙河子组地层(3 730~4 500 m)孔隙度主要分布在5%~9%,脆性指数主要分布在45%~60%,临近烃源岩TOC含量普遍较高且累计厚度较大,识别出3 798 ~3 831 m、3 950~3 990 m、4 150~4 200 m是具有勘探开发潜力的有利致密气层段。利用元素俘获能谱评价致密气储层结果准确,能为深层致密气储层优选及压裂改造提供参考依据。     

Sulfur Mass Fractions in Thirty-Seven Geological Reference Materials by Titration,XRF and Elemental Analyser

Although sulfur is a relatively abundant element, measurement results with small uncertainties remain challenging to achieve, especially at S mass fractions below 100 μg g^-1. We report > 1700 measurement results of S for thirty-seven geological reference materials including igneous, metamorphic and sedimentary rocks, and one soil. Measurement results were obtained in two laboratories (Macquarie GeoAnalytical and Géosciences Montpellier) over a long period of time ≈ 25 years (1997–2022), using several measurement procedures: X-ray fluorescence, high temperature iodo titration and elemental analysers equipped with thermal conductivity and/or infra-red detectors. Sulfur mass fractions for these diverse geological reference materials range between 5.5 and 11,395 μg g^-1. While the comprehensive data set reported here should contribute significantly to a better characterisation of the S mass fractions of widely used geological reference materials, computed uncertainties, data distribution and comparison to published values still indicate heterogeneous distribution of S carrier(s) and analytical bias.     

88ka以来冲绳海槽北部古环境演化:来自元素地球化学的证据

对CSH1岩心全样沉积物样品进行元素地球化学分析,揭示了过去88ka冲绳海槽北部沉积物成分、水动力条件及陆源碎屑物质源区风化历史。冲绳海槽北部碎屑沉积物母岩主要以长英质为主,在MIS 1期沉积物存在大量火山源物质。过去88ka,沉积物源区风化程度较弱,但是自冰消期以来有逐渐增强的趋势。沉积物Zr/Nb比值表明在MIS 1期和MIS 5.1期水动力较为强烈,这与黑潮增强的时间一致,可能是指示黑潮强度的一个指标。冲绳海槽北部陆坡沉积物陆源碎屑贡献在低海平面时期显著增加,而在MIS 1和MIS 5.1期生源贡献显著增加。冲绳海槽北部沉积物成分变化明显受到黑潮和入海径流的调节,实际上受海平面和东亚季风的制约。     

大叶藻的热值和元素含量(碳、氮、磷)及其相关性 *

提要:选取辽宁獐子岛近岸海域大叶藻样品,对其根系、根状茎和不同生长阶段叶片的灰分含量、热值和元素含量(碳、氮、磷)及其相关性进行研究,结果表明：在不同生长阶段,叶片长度随着生长顺序先增大后减小;灰分含量随着叶片生长逐渐升高,且极显著小于根状茎和根系(P<0.01);不同部位干质量热值差异极显著(P<0.01),以初生叶最高,为14894.36±40.25 Jg-1,后逐渐减小,在根系中最小,为8153.81±78.91 Jg-1;不同生长阶段叶片的去灰分热值差异不大,但大于根系和根状茎;碳氮磷含量均呈同一趋势：初生叶>幼叶>成熟叶1>成熟叶2>衰老叶>根状茎>根系;N/P比值为12.23,说明大叶藻存在N限制;N/P比值在根状茎中最大,根系中最小,这说明大叶藻存在能量的转移和存贮;大叶藻不同部位灰分含量与干质量热值、去灰分热值、碳含量、氮含量、磷含量之间呈极显著的负相关(P<0.01),干质量热值与碳含量、氮含量、磷含量之间呈极显著的正相关(P<0.01);大叶藻不同部位的热值与碳氮磷元素含量之间均呈显著的线性关系(P<0.05)。     

响应面法优化鱿鱼(Ommastrephes bartrami)皮胶原蛋白提取液脱色工艺

采用活性炭吸附法脱除鱿鱼(Ommastrephes bartrami)皮胶原蛋白提取液中色素,优化脱色条件,以进一步利用鱿鱼皮胶原蛋白。在确定该色素特征吸收波长为420 nm条件下,分别研究了活性炭添加量、脱色时间、溶液p H值和脱色温度对鱿鱼皮胶原蛋白液色素脱除效果影响。在单因素实验基础上,选择脱色时间30 min,进行活性炭添加量、溶液p H值、脱色温度三因素三水平BoxBehnken中心组合响应面分析试验。结果表明,活性炭吸附鱿鱼皮胶原蛋白液色素最佳条件为活性炭添加量4.2%,溶液p H值2.27,脱色温度35°C,该条件下鱿鱼皮胶原蛋白液的脱色率为45.6%,蛋白质和氨基酸损耗率分别为19.65%和22.93%。脱色后鱿鱼皮胶原蛋白的甘氨酸含量最高(136.02 mg/g,相对含量23.05%),谷氨酸、精氨酸和脯氨酸含量也较高,而半胱氨酸和蛋氨酸总量不到1%,符合水产蛋白氨基酸和I型胶原蛋白氨基酸特点。     

Elemental and organic carbon in atmospheric aerosols at downtown and suburban sites in Prague

Organic and elemental carbon (OC and EC) content in PM₁₀ was studied at two sites in Prague, which were located in a suburb and in the downtown. Similar overall average levels were found for both species and also for the PM₁₀ mass at the two sites (i.e., 5.5 and 4.8 μg/m³ for OC, 0.74 and 0.80 μg/m³ for EC, and 33 μg/m³ and 37 μg/m³ for the PM₁₀ mass at the suburb and downtown site, respectively), but substantial differences were observed between the two sites in some seasons and/or meteorological situations. Approximately three times higher values were found for OC in winter compared to summer, with a higher winter/summer ratio for the suburban site. The differences for EC were smaller, but still, compared to summer, more than two times higher EC levels were observed during autumn at the suburban site and 1.5 higher EC levels in winter and autumn at the downtown site. The lowest OC to EC ratios at the suburban site were 3.4, while they were around 1.3 for the downtown site. It was found that the origin of the air masses had a major impact on the observed PM₁₀ mass and OC levels, with largest concentrations noted for air masses recirculating over central Europe and arriving from southeastern Europe in winter. Trajectories coming from the west and northwest originating above the Atlantic Ocean and the Artic brought the cleanest air masses to the sites. For EC the largest difference between the two sites was observed for northwesterly winds during the non-heating season when the suburban site was upwind of Prague.     

Chemical Characteristics of Carbonaceous Aerosols During Dust Storms over Xi'an in China

Characterization of carbonaceous aerosols including CC （carbonate carbon）, OC （organic carbon）, and EC （elemental carbon） were investigated at Xi＇an, China, near Asian dust source regions in spring 2002. OC varied between 8.2 and 63.7μgm^- 3, while EC ranged between 2.4 and 17.2 μ m^-3 during the observation period. OC variations followed a similar pattern to EC and the correlation coefficient between OC and EC is 0.89 （n=31）. The average percentage of total carbon （TC, sum of CC, OC, and EC） in PM2.5 during dust storm （DS） events was 13.6%, which is lower than that during non-dust storm （NDS） periods （22.7%）. CC, OC, and EC accounted for 12.9%, 70.7%, and 16.4% of TC during DS events, respectively. The average ratio of OC/EC was 5.0 in DS events and 3.3 in NDS periods. The OC-EC correlation （R^2=0.76, n=6） was good in DS events, while it was stronger （R^2=0.90, n=25） in NDS periods. The percentage of watersoluble OC （WSOC） in TC accounted for 15.7%, and varied between 13.3% and 22.3% during DS events. The distribution of eight carbon fractions indicated that local emissions such as motor vehicle exhaust were the dominant contributors to carbonaceous particles. During DS events, soil dust dominated the chemical composition, contributing 69% to the PM2.5 mass, followed by organic matter （12.8%）, sulfate （4%）, EC （2.2%）, and chloride （1.6%）. Consequently, CC was mainly entrained by Asian dust. However, even in the atmosphere near Asian dust source regions, OC and EC in atmospheric dust were controlled by local emission rather titan the transport of Asian dust.     

氢化物发生-原子荧光光谱法测定植物样品中汞硒砷

植物样品经硝酸-高氯酸一次湿法消解后,用氢化物发生-原子荧光光谱法同时测定汞、硒、砷。测定时加入消泡剂磷酸三丁酯,可有效消除泡沫,降低记忆效应,提高精密度。方法精密度(RSD,n=12)为汞2.96%,硒0.96%,砷2.49%。经加标回收试验和国家一级标准物质验证,测定结果与标准值吻合。