密闭消解HG-AFS法测定丹参植株中汞含量

为评价中江丹参植株汞含量水平、了解汞的植株分布,采用HNO_3-H_2O_2密闭消解、氢化物发生原子荧光法测定来自中江丹参种植基地的12个植株样品中的汞含量。实验优化还原反应条件,通过国家标准物质比较不同消解方法对测定结果的影响及验证方法的准确度和可靠性,密闭消解获得结果的准确度和精密度符合痕量分析要求。方法检出限为0.12μg/L,相对标准偏差为7.8%,样品加标回收率为81.0%~115.0%。丹参根中的汞含量未超过国家药典标准(0.2 mg/kg),部分茎和叶含量超标,植株汞含量分布为叶茎根。     

测汞仪直接测定空气颗粒物中的总汞

采用配备热解装置的测汞仪直接测定空气颗粒物中的总汞,通过对实验条件的筛选及优化,得到最佳条件。采用石英纤维滤膜采集一定空气颗粒物样品,将石英纤维滤膜放在石英舟中,然后将样品舟插入到原子化器中对样品进行解析,可直接测量样品中汞的含量。该方法的线性相关系数r=0.999 7、精密度RSD=4.1%、回收率准确度在93%~118%之间,方法检出限可达到8×10~(-3)ng/m~3。该方法测量空气颗粒物的汞无需任何试剂和消解,测定速度快、操作简便,适合空气颗粒物中汞的测定。     

微波消解-氢化物发生原子荧光光谱法同时测定蔬菜中汞、砷

本文建立了一种梯度升压微波消解样品,氢化物发生双道原子荧光光谱法同时测定蔬菜样品中汞、砷的方法。在优化实验条件下,蔬菜样品中Hg、As回收率分别为98.9%-109.3%和91.1%-96.1%;检出限分别为0.0094μg/L、0.0331μg/L。并对其相讨标准偏差(RSD)、精密度和准确度进行了评估,结果表明该方法用于蔬菜中Hg、As的同时测定是可行的。     

应用一种微波消解液直接测定食品中7种元素

针对食品检测前处理时间和检测周期过长的难题,用硝酸及双氧水作为消解溶剂,在设定的微波消解条件下,可以将样品消解完全,消解液中加入硫脲和L盐酸,不需任何处理可直接进行砷等7种元素的测定.硫脲将高价砷和汞离子还原为三价砷和汞原子,而对其它元素无影响,从而实现氢化物发生原子荧光法同时测定食品中砷、汞的含量,原子吸收火焰法测定食品中铜、锌、铁、镁、锰的含量.通过测定标准物质和加标回收实验,对方法进行验证,结果表明,方法简便快速、准确度与精密度令人满意.     

微波消解-冷原子荧光法测定大米中汞

本文研究了以微波消解,冷原子荧光法测定大米中汞的最佳测定条件,汞含量在(0～20.0)ug.L-1范围内呈线性关系,相关系数为0.99993,检出限为0.008ug.L-1,方法应用于大米中汞的测定,样品加标回收率在97.6%～107.0%之间,相对标准偏差在1.7%-5.7%之间.     

微波消解-电感耦合等离子发射光谱法在测定土壤中34种微量元素的应用研究

微波消解-电感耦合等离子发射光谱法同时测定34种微量元素的方法,并测定了某产业园区内土壤中34种微量元素。实验对微波消解条件和质谱检测条件进行优化,在优化条件下,34种元素的线性相关系数均在0.999以上,检出限大部分满足标准要求,加标回收率在83.6～114%之间,此方法前处理操作简便,检测时间短,准确性好。     

微波消解结合ICP-MS测定内衬纸和框架纸中7种元素

目的 基于高压密封微波消解技术,构建一种新型微波消解体系,并将其与电感耦合等离子体质谱(ICP-MS)联用,用于烟用内衬纸和框架纸中铬、镍、砷、硒、镉、汞和铅元素含量的测定.方法 在新的消解体系中,用氟化铵(NH4F)代替传统方法中的氢氟酸(HF),以降低对实验操作人员的危害,并考察不同实验条件对实验结果的影响.结果 最佳消解条件为0.2 g纸质样品在6 mL硝酸和0.5 mL NH4F体系中消解,微波消解程序为温度从室温升至185°C(20 min)保持30 min后降至55°C(20 min);7种元素的标准曲线线性良好(r2>0.9990),检出限低,加样回收率和重现性良好;在检测实际样品时,与传统方法相比,该方法的测定结果无显著性差异(P>0.05).结论 该方法快速准确、安全环保,适合于烟用内衬纸和框架纸中7种元素含量的测定.     

微波消解-氢化物原子荧光光谱法同时测定金华火腿中砷和汞研究

为提高金华火腿中砷和汞的检测水平，建立了微波消解-氢化物原子荧光光度法同时测定火腿中砷和汞的方法。确定了微波消解样品的条件，优化了仪器的最佳工作参数。在最佳的试验条件下，0～10．0μg．L^-1砷和0～2．0μg．L^-1汞标准溶液，标准曲线具有良好的线性，砷、汞的检出限分别为：砷0．073μg．L^-，汞0．0055μg．L^-1；回收率砷在90．0％。110．0％之间、汞在95．0％～1．10．0％之间；相对标准偏差砷为1．26％，汞为3．08％。     

新型冷蒸气发生-原子吸收光谱测定汞及甲基汞

建立了紫外光化学蒸气发生或超声波化学蒸气发生-原子吸收光谱测定汞及甲基汞的新方法,考察了相关的实验条件和仪器条件.在超声波的条件下测定无机汞(检出限为0.1μg·L-1),在紫外光的条件下测定总汞,然后通过差减法来实现不经色谱分离测定汞和甲基汞(汞和甲基汞检出限为0.08μg·L-1).实际样品的加标回收率在94%～110%之间,该方法具有简单、绿色、灵敏的特点.     

双道原子荧光光谱法同时测定土壤中的汞和硒

建立了同时测定土壤中汞和硒的原子荧光光谱法。对试样的预处理和消解方法进行了详述。试样的相对标准偏差Hg为3.60%,回收率在90%~109%之间;Se为4.10%,回收率在92~101%之间。汞和硒的检出限分别为0.051μg.L-1和0.29μg.L-1。本方法操作简便、快速、灵敏度高。     

海泥中硫酸盐还原菌对1Cr13不锈钢腐蚀的影响

利用交流阻抗测试技术，扫描电镜及表面能谱、失重法、微生物分析等方法，在室内模拟条件下研究了海泥中硫酸盐还原菌对1Cr13不锈钢腐蚀的影响，及在含和不含硫酸盐还原菌的海泥构成的宏电池腐蚀中1Cr13不锈钢的腐蚀行为。试验结果表明，在有菌泥中1Cr13不锈钢的自然腐蚀速度均大于在灭菌泥中，两相差5．1倍。说明海泥中硫酸盐还原菌增大了1Cr13不锈钢的腐蚀速率。在有菌和灭菌海泥构成宏电池时，有菌海泥中1Cr13不锈钢作为阳极，腐蚀速率比自然腐蚀状态下有所增大，加速率为14．6％。而在灭菌海泥中1Cr13不锈钢作为阴极，腐蚀速率比自然腐蚀状态下有所减小。     

斜坡海底海洋环境噪声垂直指向性研究

为了解决斜坡海底地形的环境噪声高频建模问题,为三维环境噪声的进一步计算奠定了基础。在射线法的基础上,采用N×2D的近似算法,研究了斜坡海底情况下,均匀分布在海面上的噪声源所产生的环境噪声垂直指向性。考虑了海水吸收,海底反射,声速剖面对垂直指向性计算结果的影响。研究表明：三种因素均会对斜坡海底的噪声垂直指向性产生影响,其中声速剖面对其影响要大一些。     

Establishment of long-term preservation for dimethyl sulfide by the solid-phase microextraction method

Dimethyl sulfide (DMS) derived from marine biological activity affects radiative forcing of the climate. The general analytical technique for DMS in seawater (purge and trap analytical method, P&T) is complex onboard ship. Thus it is difficult to obtain sufficient data for a comprehensive understanding of the spatiotemporal variability of DMS in the sea surface layer. On the other hand, a new analytical method for DMS using SPME (solid-phase microextraction) has recently been developed as an alternative method to P&T. This method is simpler than P&T because no special or complex apparatus is needed. If it is possible to preserve DMS for an extended period in excess of the duration of the cruise, the SPME method is a promising method for measuring DMS in seawater. We assessed an analytical method which can allow us to preserve DMS on the long-term scale using SPME. In liquid nitrogen (-196 degrees C), as preserved environment, for a period of 20 days after sampling, we found the preservation rate of DMS to be 94.7 +/- 4.4% (n = 6) in this study. Furthermore, estimating the distribution coefficient with respect to the effect of salinity on SPME, we found that DMS changed by 0.1 nM/% sal, suggesting that salinity has only a minor influence on oceanic DMS measurements in the open ocean because the minimal change of the open ocean salinity is within 2 %. Applying the SPME method to open ocean samples, we found that there were no significant differences in DMS between the unpreserved and preserved samples (r = 0.99, n = 26, SE = 0.01, p < 0.0001), showing the SPME method has potential for use for open ocean surveys.     

极地钢铁材料的腐蚀与防护面临新挑战

随着极地的开发和利用,其所需的极地钢铁材料的腐蚀与防护问题越来越受到研究者的关注。本文以传统海洋环境腐蚀分区为参照,对极地特色的腐蚀环境进行了系统的分析,并将其归纳整理为极地大气区、极地冰水磨蚀区、极地海洋全浸区、极地海底泥土区等4个腐蚀区域。在对极地钢铁材料腐蚀与防护的研究进展进行梳理的基础上,从合金化、涂层技术和阴极保护技术3个方面介绍了极地钢铁材料的防护技术,并指出了极地钢铁材料未来研究的方向。     

Determination of low molecular weight dicarboxylic and ketocarboxylic acids in seawater samples

We report a new method developed for the isolation and determination of low molecular weight dicarboxylic acids and related polar compounds (C2-C9) from seawater samples. The seawater sample was first acidified and then passed through an activated charcoal column to adsorb the dicarboxylic acids. They are then desorbed with NH4OH/methanol/water mixture and derivatized with BF3/1-butanol to dibutyl esters, which are determined using a capillary GC/FID. We tested different pH (0.5, 1, 1.5) and different amounts of charcoal (100, 200, 300, 500 mg) to maximize the recovery of dicarboxylic acids. Using 300 mg of activated charcoal for 100 mL of sodium chloride solution acidified at pH 1, the recoveries for C2, C3, C4, C5, C6, C7, C8, and C9 were 61, 49, 96, 84, 77, 67, 57, and 53%, respectively. We applied this method to real seawater samples collected from the northwestern Mediterranean Sea. Here, we report, for the first time, concentrations of a homologous series of C2-C9 dicarboxylic acids as well as ketocarboxylic acids including glyoxylic and 4-oxobutanoic acids in surface water and deep seawater samples, with glyoxylic acid being the dominant species (8-40 microg L(-1)). This method allows the detection of dicarbonyls such as glyoxal in the samples although its quantification is not possible.     

膜生物反应器处理冲厕海水的试验研究

主要研究了膜生物反应器对冲厕海水中主要污染物的处理效果以及盐度对生物反应器内微生物群落和活性污泥特性的影响.结果表明,微生物经培养驯化后能适应不同的海水盐度,膜生物反应器对冲厕海水中的COD和氨氮的去除率分别达到86%和93%.随着盐度的提高,污泥沉降性能变差.盐度的冲击对膜生物反应器处理效果有一定影响,系统需要较为恒定的盐度条件.     

Study on steel corrosion in different seabed sediments

A series of simulation experiments on carbon steel (A₃ steel) and low alloy steel (16 Mn steel) in marine atmosphere (MA), seawater (SW) and seabed sediment (SBS) including rough sea sand, fine sea sand and seabed mud were carried out indoors for a year or so by means of individually hanging plates (IHP) and electrically connected hanging plates (ECHP). The corrosion of steels in SBS was mainly due to the macrogalvanic cell effect. The steel plates at the bottom of SBS, as the anode of a macrogalvanic cell, showed the heaviest corrosion with a corrosion rate of up to 0·12 mm/a, approximately equal to that of steel plates in marine atmosphere. The test results showed that the corrosion rates of A₃ and 16 Mn steel in marine environment were in the order: MA>SW>SBS by the IHP method; and MA>SBS>SW by the ECHP method. The corrosion rates of steels in the water/sediment interface were directly proportional to the grain size of the SBS by the ECHP method, but those of steels in the water/sediment interface did not vary with the grain size of SBS by the IHP method. The corrosion rate of low-alloy steel was a little higher than that of carbon steel. The results of this study have important applications for design of offshore steel structures such as oil platform, pier, and port.     

Flexural properties of z-pinned composite laminates in seawater environment

Unidirectional carbon-fibre reinforced composite laminates with and without z-pins were immersed in artificial seawater and exposed to two different temperature levels (?1.75 and 50 °C), as well as thaw–freeze cycles (+20/?20 °C). The investigation described is focused on the question to which degree seawater absorption, as well as bending properties are influenced by z-pin reinforcement. The results indicate an increasing influence of the z-pin reinforcement on the water sorption rate, while the sorption rate of unpinned laminates is lower. This is a result of the additional diffusion pathways of the moisture ingress into the laminate caused by the inserted z-pins which in turn change the micro-structure. Furthermore, the sorption rate depends on the immersion temperature. Laminates immersed into seawater with higher temperatures (50 °C) display a significantly higher diffusion rate than those immersed in colder seawater (?1.75 °C) or those immersed under thaw–freeze conditions (+20/?20 °C). Z-pin reinforced laminates with a unidirectional fibre orientation show a reduced bending strength by about 31 %, as well as a reduced flexural modulus by about 11 % in comparison to unpinned samples. Unpinned and z-pinned samples that were exposed to a seawater environment for 1344 h show a reduced flexural modulus depending on the immersion temperatures. As opposed to flexural modulus, flexural strength is not affected by immersion time or temperature. The overall bending strain energy that is necessary for a complete fracture of the unpinned samples under 4-point bending loads can be described with the value of the elastic bending strain energy. In contrast to this the overall bending strain energy of the z-pinned laminates is composed of two different components –the elastic bending strain energy and the post-fracture strain energy. The post-fracture strain energy occurs after exceeding the flexural strength. The overall bending strain energy of z-pinned and unpinned samples without immersion into seawater is around 7.2 J, while the percentage of the post-fracture energy of the pinned samples is 40 % with respect to the overall bending strain energy. The duration of the immersion into water and higher water temperatures increases the overall bending strain energy for both unpinned and pinned samples. The increase is higher for z-pinned samples and is mainly caused by the increase of the post-fracture energy.     

Phosphate removal from wastewater using red mud

Red mud, a waste residue of alumina refinery, has been used to develop effective adsorbents to remove phosphate from aqueous solution. Acid and acid-thermal treatments were employed to treat the raw red mud. The effects of different treatment methods, pH of solution and operating temperature on adsorption have been examined in batch experiments. It was found that all activated red mud samples show higher surface area and total pore volume as well as higher adsorption capacity for phosphate removal. The red mud with HCl treatment shows the highest adsorption capacity among all the red mud samples, giving adsorption capacity of 0.58 mg P/g at pH 5.5 and 40 degrees C. The adsorption capacity of the red mud adsorbents decreases with increase of pH. At pH 2, the red mud with HCl treatment exhibits adsorption of 0.8 mg P/g while the adsorption can be lowered to 0.05 mg P/g at pH 10. However, the adsorption is improved at higher temperature by increasing 25% from 30 to 40 degrees C. The kinetic studies of phosphate adsorption onto red mud indicate that the adsorption mainly follows the parallel first-order kinetics due to the presence of two acidic phosphorus species, H(2)PO(4)(-) and HPO(4)(2-). An analysis of the adsorption data indicates that the Freundlich isotherm provides a better fitting than the Langmuir model.     

Trypsin immobilization on hairy polymer chains hybrid magnetic nanoparticles for ultra fast, highly efficient proteome digestion, facile 18O labeling and absolute protein quantification

In recent years, quantitative proteomic research attracts great attention because of the urgent needs in biological and clinical research, such as biomarker discovery and verification. Currently, mass spectrometry (MS) based bottom up strategy has become the method of choice for proteomic quantification. In this strategy, the amount of proteins is determined by quantifying the corresponding proteolytic peptides of the proteins, therefore highly efficient and complete protein digestion is crucial for achieving accurate quantification results. However, the digestion efficiency and completeness obtained using conventional free protease digestion is not satisfactory for highly complex proteomic samples. In this work, we developed a new type of immobilized trypsin using hairy noncross-linked polymer chains hybrid magnetic nanoparticle as the matrix aiming at ultra fast, highly efficient proteomic digestion and facile (18)O labeling for absolution protein quantification. The hybrid nanoparticle is synthesized by in situ growth of hairy polymer chains from the magnetic nanoparticle surface using surface initiated atom transfer radical polymerization technique. The flexible noncross-linked polymer chains not only provide large amount of binding sites but also work as scaffolds to support three-dimensional trypsin immobilization which leads to increased loading amount and improved accessibility of the immobilized trypsin. For complex proteomic samples, obviously increased digestion efficiency and completeness was demonstrated by 27.2% and 40.8% increase in the number of identified proteins and peptides as well as remarkably reduced undigested proteins residues compared with that obtained using conventional free trypsin digestion. The successful application in absolute protein quantification of enolase from Thermoanaerobacter tengcongensis protein extracts using (18)O labeling and MRM strategy further demonstrated the potential of this hybrid nanoparticle immobilized trypsin for high throughput proteome quantification.