AS17-C色谱柱手册

IonPac AS17-C色谱柱是一支氢氧化物选择性的、专门进行梯度淋洗分离无机阴离子的阴离子交换分离柱,其主要应用于检测高纯水中的无机阴离子.     

离子色谱中常用的改善分离度方法

1　稀释样品对组成复杂的样品 ,若待测离子对树脂亲合力相差颇大 ,就要作几次进样 ,并用不同浓度或强度的淋洗液或梯度淋洗 .对固定相亲合力差异较大的离子 ,增加分离度的最简单方法是稀释样品或作样品前处理 .例如盐水中ＳＯ2 -4 和Ｃｌ- 的分离 .若直接进样 ,其色谱峰很宽而且拖尾 ,表明进样量已超过分离柱容量 ,在常用的分析阴离子的色谱条件下 ,3 0ｍｉｎ之后Ｃｌ- 的洗脱仍在继续 .在这种情况下 ,在未恢复稳定基线之前不能再进样 .若将样品稀释 1 0倍之后再进样就可得到Ｃｌ- 与痕量ＳＯ2 -4 之间的较好分离 .对阴离子分析推荐的最大进…     

离子色谱法测定饮用水和面包中的溴酸根

选用ＡＳ９－ＨＣ高容量阴离子交换色谱柱,不需处理除去干扰离子,可直接进样。测定了两种水样,其中一种检出溴酸根,方法检出根０．００５ｍｇ．１＾－１水样加标回收率９１．３－９３．４％。采用全新的自动化样品处理技术－加速溶剂萃取萃取面包中的溴酸根。经ＡＳ９－ＳＣ阴离子交换色谱柱分离,选择最佳淋洗条件。电导检测,方法检 ０．０７ｍｇ．１＾－１,对十二种市售包进行测定,均未检出溴酸根,样品加标回收率７９．９     

青枯菌不同色谱峰组分的细胞表面特性

将高效离子交换色谱应用于植物重要致病菌——青枯菌的分离分析.青枯菌纯培养物经过色谱分离得到3个特征峰,收集3个色谱峰组分进行形态观察和生理生化鉴定,结果表明3个组分均属于青枯菌生化Ⅲ型;进一步分析发现,3个色谱峰组分在质粒DNA、细胞表面鞭毛菌毛蛋白含量和全细胞脂多糖成分方面无明显差异,但细胞表面黏附的胞外酸性多糖EPSⅠ含量差异显著;3个色谱峰青枯菌细胞表面疏水性的测定结果也证实了EPSⅠ是造成不同青枯菌细胞色谱行为差异的主要原因.高效离子交换色谱为细菌活细胞的研究提供了一种新方法.图4表2参15     

新型离子色谱柱对常见阴离子分析的应用研究

抑制型电导检测离子色谱法分析常见阴离子已广泛应用于各个领域,但是阴离子分离过程中,水负峰与F-淋洗位置及CI~-,NO_ 2~-之间的保留时间相差不大,容易影响F~-和NO_2~-定量的准确性;其次.对基体复杂的样品分析,需要更大交换容量的分离柱抗干扰.本文首次选择IonPac AS14阴离于交换分离柱,由于该柱填料具有较强的疏水性及较大的交换容量(65μeq/柱)等特性,不仅改善了水负峰和F~-,CI-和NO_2~-的分高度,而且为其在复杂基体样品分析中的应用开辟了广泛的前景.     

使用CarboPac PA200柱测定植物提取液中的中性寡糖和多聚糖

采用新型的阴离子交换柱对高聚合度多聚糖进行离子色谱法鉴定.应用CarboPac PA200分析柱(3mm×250mm)与TSKgel superIC-AZ(4.6mm×1cm)保护柱,柱温30℃,100 mmo.ll-1NaOH和100 mmol.l-1NaOH/1 mol.l-1醋酸钠作为淋洗液,流速为0.5ml.min-1,脉冲安培检测器.结果表明,该阴离子交换柱分析速度快,分离效果好,柱效高,可用于植物提取液中中性寡糖和多聚糖的测定.     

无需柱前柱后衍生的氨基酸直接分析技术--细胞培养基与发酵液中氨基酸的测定

大多数氨基酸具有弱发光基团,在高浓度时才可用紫外吸收检测.发酵液或细胞培养基中的许多成分也具有发色团,用吸收法检测时这些成分会干扰氨基酸的直接检测.因此,可以用安培法直接检测这类物质.积分脉冲安培检测法(IPAD)是一种强大的检测技术,它有很宽的线性范围和很低的检测限.采用AminoPac PA10阴离子交换柱可以分离所有常见的氯基酸.AAA-DirectTM将阴离子交换(AE)和IPAD两种方法结合起来.可以同时检测复杂样品中的糖、乙二醇、糖醇(醛醇)和氨基酸.     

测定无机阴离子和低分子量有机酸的新型阴离子交换柱

AS1 8柱是氢氧化物选择性阴离子交换柱 ,用于测定无机阴离子和低分子量的有机酸 ,包括F- ,乙酸根 ,甲酸根 ,Cl- ,NO-2 ,SO2 -4 和PO3-4 等 .AS1 8柱可用于氢氧化物等度淋洗或梯度淋洗 .建议与氢氧化钾淋洗液在线淋发生器EG40或EG5 0结合使用 .AS1 8柱的高容量和选择性为优化阴离子的分离提供了灵活性 .AS1 8柱用于以氢氧化物为淋洗液 ,等度快速分离简单基体样品中的常见无机阴离子是很理想的 .AS1 8柱容量高 ,可使用氢氧化物梯度淋洗液以及大体积进样来测定复杂基体样品中低浓度级别的无机阴离子 ,包括饮用水和废水 .美国EPA水质…     

可根据需要调节容量的新型阴离子交换柱

可调容量阴离子交换柱 (ＩｏｎＰａｃＣｒｙｐｔａｎｄＡ1 )其柱容量可通过改变淋洗液中阳离子的浓度和种类来调节 .ＣｒｙｐｔａｎｄＡ1柱使用的淋洗液可为氢氧化锂、氢氧化钠或氢氧化钾 ,因而柱容量范围各不相同 .可变的柱容量对使用低浓度淋洗液、快速洗脱多价阴离子是很理想的 .优越的色谱性能◆　多价阴离子的测定 ,包括多磷酸盐和多磺酸盐◆　 1 0ｍｉｎ内完成常见阴离子和可极化阴离子的测定◆　柱选择性的最佳条件 :操作温度 3 5℃ ,以保证保留时间的重现性◆　氢氧化钠和氢氧化锂淋洗液作容量梯度 ,适用于大多数多价阴离子的测定◆…     

青枯菌野生型菌株和无毒突变株细胞表面的吸附特性(英文)

应用高效离子交换色谱和激光光散射仪检测器(HPLC/MALLS)研究青枯菌野生型菌株79#和无毒突变菌株RS52’对强阴离子交换树脂(SuperQ-650C)的吸附特性.结果显示,这2个菌株在色谱行为和吸附特性方面差异显著.静态吸附试验结果也表明,在相同条件下,79#菌株的吸附速率和吸附量与RS52’菌株不同,79#菌株在60min达到吸附平衡,最大吸附量为1.09×109cfu/g(干树脂);RS52’菌株在120min达到吸附平衡,最大吸附量为2.10×10~9cfu/g(干树脂).进一步采用Langmuir和Freundlich吸附等温线方程比较79#菌株和RS52’菌株与树脂之间的吸附能力,研究结果与静态吸附试验结果以及高效离子交换色谱的分析结果相一致,RS52’菌株与树脂之间显示出更强的吸附力;此外,用Freundlich方程拟合的效果优于Langmuir方程,拟合的曲线与实验数据更吻合.图4表2参16     

Achieving Open Access to Conservation Science

Conservation science is a crisis discipline in which the results of scientific enquiry must be made available quickly to those implementing management. We assessed the extent to which scientific research published since the year 2000 in 20 conservation science journals is publicly available. Of the 19,207 papers published, 1,667 (8.68%) are freely downloadable from an official repository. Moreover, only 938 papers (4.88%) meet the standard definition of open access in which material can be freely reused providing attribution to the authors is given. This compares poorly with a comparable set of 20 evolutionary biology journals, where 31.93% of papers are freely downloadable and 7.49% are open access. Seventeen of the 20 conservation journals offer an open access option, but fewer than 5% of the papers are available through open access. The cost of accessing the full body of conservation science runs into tens of thousands of dollars per year for institutional subscribers, and many conservation practitioners cannot access pay‐per‐view science through their workplace. However, important initiatives such as Research4Life are making science available to organizations in developing countries. We urge authors of conservation science to pay for open access on a per‐article basis or to choose publication in open access journals, taking care to ensure the license allows reuse for any purpose providing attribution is given. Currently, it would cost $51 million to make all conservation science published since 2000 freely available by paying the open access fees currently levied to authors. Publishers of conservation journals might consider more cost effective models for open access and conservation‐oriented organizations running journals could consider a broader range of options for open access to nonmembers such as sponsorship of open access via membership fees. Obtención de Acceso Abierto a la Ciencia de la Conservación     

Rapid,recurring, structured survey versus bioblitz for generating biodiversity data and analysis with a multispecies abundance model

A bioblitz inexpensively and quickly generates biodiversity data, but bioblitzes are often conducted with haphazard, unreplicated sampling. Results tend to be taxonomically, geographically, or temporally biased, lack metadata, and consist of lists of observed taxa that do not enable further analyses or correction for imperfect detection. A rapid, recurring, structured survey (RRSS) uses a structured sampling design and temporal and spatial replication to survey randomly selected sites on a conservation property. We participated in a loosely structured bioblitz and a subsequent RRSS at Big Canoe Creek Nature Preserve in Springville (St. Clair County), Alabama (USA) to compare observed richness derived from the 2 survey approaches. The RRSS data structure enabled us to fit models that accounted for imperfect detection to estimate abundances, occupancy probabilities, and habitat associations. The loosely structured bioblitz data could not be used in such models. We present a new integrated multispecies abundance model that we applied to avian RRSS data. Our model extension enables estimation for the community, employs data augmentation to estimate the number of undetected species, and incorporates covariates. The RRSS generated a more comprehensive and less biased list of observed taxonomic richness than the loosely structured bioblitz (e.g., 73 vs. 45 bird species and 104 vs. 63 insect families from the RRSS vs. loosely structured bioblitz, respectively). Models fit to the RRSS data identified seasonal patterns in avian community composition and allowed for estimation of habitat–occupancy relationships for insect taxa. The RRSS protocol has potential for broad transferability as a standardized, quick, and inexpensive way to inventory biodiversity and estimate ecological parameters while providing an outreach opportunity.     

Compliance with and ecosystem function of biodiversity offsets in North American and European freshwaters

Land-use change via human development is a major driver of biodiversity loss. To reduce these impacts, billions of dollars are spent on biodiversity offsets. However, studies evaluating offset project effectiveness that examine components such as the overall compliance and function of projects remain rare. We reviewed 577 offsetting projects in freshwater ecosystems that included the metrics project size, type of aquatic system (e.g., wetland and creek), offsetting measure (e.g., enhancement, restoration, and creation), and an assessment of the projects’ compliance and functional success. Project information was obtained from scientific and government databases and gray literature. Despite considerable investment in offsetting projects, crucial problems persisted. Although compliance and function were related to each other, a high level of compliance did not guarantee a high degree of function. However, large projects relative to area had better function than small projects. Function improved when projects targeted productivity or specific ecosystem features and when multiple complementary management targets were in place. Restorative measures were more likely to achieve targets than creating entirely new ecosystems. Altogether the relationships we found highlight specific ecological processes that may help improve offsetting outcomes.     

Some polyphagous Homoptera gain protection from their natural enemies by feeding on the toxic plantsSpartium junceum andErythrina corallodendrum (Leguminosae)

Summary Interactions were studied among alkaloid-containing legumes (Erythrina corallodendrum andSpartium junceum) and non-toxic plants (Citrus sinensis, Cucurbita moschata andEuphorbia tirucalli), several polyphagous homopterans,Aphis craccivora (Aphididae),Icerya purchasi, I. aegyptiaca (Margarodidae),Lepidosaphes ulmi (Diaspididae) andPlanococcus citri (Pseudococcidae), and some major natural enemies of these homopterans. Significant reductions in survival due to negative effects of alkaloid containing as compared with non-alkaloidal plants were recorded for the predatorsRodolia cardinalis andChilocorus bipustulatus, but not forCryptolaemus montrouzieri (Coleoptera: Coccinellidae),Chrysoperla carnea (Neuroptera: Chrysopidae) andSympherobius sanctus (Neuroptera: Sympherobiidae). The development time of the larvae or pupae ofR. cardinalis, C. carnea andS. sanctus was longer on the toxic plants than on the non-toxic ones. The percentage of parasitism ofA. craccivora collected from the non-alkaloidal plantsVicia palaestina andMelilotus albus was much higher than that onS. junceum. The parasitoid complexes ofA. craccivora differed between both plant groups. The nutritive value of honeydew ofI. purchasi andA. craccivora, as expressed by the life span ofEncyrtus infelix (Hymenoptera: Encyrtidae) adults, was also investigated. Life spans were significantly longer when the wasps fed on honeydew produced on non-alkaloidal plants (C. sinensis andPittosporum tobira) than on alkaloid containing plants whenI. purchasi — but notA. craccivora — was the producer. It is suggested that the chemical defense ofE. corallodendrum andS. junceum is exploited by polyphagous phytophages to reduce predation. In nature, population growth and density of four of the investigated homopterans are conspicuously high when they developed on the alkaloid containing plant species, and very low on non-alkaloid plants. The efficiency of their natural enemies may be reduced by sequestration of alkaloids (or other toxic plant compounds) or their transfer into excreted honeydew. Therefore it is assumed that a generalist phytophagous homopteran may be protected from its natural enemies, although at different rates of efficiency, if it can safely sequester the host allelochemical when it develops on toxic species within its host range.     

A palaeo-hydrogeological model for arsenic contamination in southern and south-east Asia

An argument is presented in which areas of natural arsenic contamination of modern groundwaters throughout Asia have a common origin. Arsenic originally accumulated in oceanic ferro-manganoan sediments of the eastern Palaeo-Tethys. This was further concentrated through oceanic crustal extinction in what later became the south-east Chinese accreted mineralised terrain. Proto-Himalayan uplift of this area created the palaeo-drainage systems of the Ganges – Brahmaputra, Irrawaddy, Mekong, and Red Rivers, with consequent headwater erosion of arsenic-rich sediments. Their downstream deposition as immature and easily redistributed Neogene sandstones, silts, and iron-rich clays has created secondary and tertiary reservoirs of adsorbed and authigenic arsenic, from which the current arsenic-rich groundwaters have evolved. Considering river basins within the above palaeo-hydrogeological framework provides a basis for assessing the risk of arsenic in groundwater basins of south and south-eastern Asia.     

Sequestration of cucurbitacin analogs by New and Old World chrysomelid leaf beetles in the tribe Luperini

Summary Two South American polyphagous leaf beetles,Diabrotica speciosa andCerotoma arcuata, selectively accumulated the bitter tasting compound 23,24-dihydrocucurbitacin D in their body after ingesting root tissues of cucurbit plants. Similarly, three Asian Cucurbitaceae-feeding specialists in the genusAulacophora were found to sequester the same compound. Cucurbitacin analogs were shown to deter feeding by a bird predator, indicating an allomonal role for these compounds in cucurbitacin-associated chrysomelid leaf beetles both of New and Old Worlds. The strong affinity to cucurbitacins, selective sequestration of the analogs and consequent protection from predators suggested an ecological adaptation mechanism developed in common among these two geographically isolated subtribes in the Luperini.     

Threats to intact tropical peatlands and opportunities for their conservation

Large, intact areas of tropical peatland are highly threatened at a global scale by the expansion of commercial agriculture and other forms of economic development. Conserving peatlands on a landscape scale, with their hydrology intact, is of international conservation importance to preserve their distinctive biodiversity and ecosystem services and maintain their resilience to future environmental change. We explored threats to and opportunities for conserving remaining intact tropical peatlands; thus, we excluded peatlands of Indonesia and Malaysia, where extensive deforestation, drainage, and conversion to plantations means conservation in this region can protect only small fragments of the original ecosystem. We focused on a case study, the Pastaza‐Marañón Foreland Basin (PMFB) in Peru, which is among the largest known intact tropical peatland landscapes in the world and is representative of peatland vulnerability. Maintenance of the hydrological conditions critical for carbon storage and ecosystem function of peatlands is, in the PMFB, primarily threatened by expansion of commercial agriculture linked to new transport infrastructure that is facilitating access to remote areas. There remain opportunities in the PMFB and elsewhere to develop alternative, more sustainable land‐use practices. Although some of the peatlands in the PMFB fall within existing legally protected areas, this protection does not include the most carbon‐dense (domed pole forest) areas. New carbon‐based conservation instruments (e.g., REDD+, Green Climate Fund), developing markets for sustainable peatland products, transferring land title to local communities, and expanding protected areas offer pathways to increased protection for intact tropical peatlands in Amazonia and elsewhere, such as those in New Guinea and Central Africa which remain, for the moment, broadly beyond the frontier of commercial development.     

Effects of Controlled Fire and Livestock Grazing on Bird Communities in East African Savannas

Abstract: In East Africa fire and grazing by wild and domestic ungulates maintain savannas, and pastoralists historically set fires and herded livestock through the use of temporary corrals called bomas. In recent decades traditional pastoral practices have declined, and this may be affecting biodiversity. We investigated the effects of prescribed fires and bomas on savanna bird communities in East Africa during the first and second dry seasons of the year (respectively before and after the rains that mark the onset of breeding for most birds). We compared abundance, richness, and community composition on 9‐ha burned plots, recently abandoned bomas, and control plots in the undisturbed matrix habitat over a 3‐year period. Generally, recently burned areas and abandoned bomas attracted greater densities of birds and had different community assemblages than the surrounding matrix. The effects of disturbances were influenced by interactions between primary productivity, represented by the normalized difference vegetation index, and time. Bird densities were highest and a greater proportion of species was observed on burned plots in the months following the fires. Drought conditions equalized bird densities across treatments within 1 year, and individuals from a greater proportion of species were more commonly observed on abandoned bomas. Yearly fluctuations in abundance were less pronounced on bomas than on burns, which indicate that although fire may benefit birds in the short term, bomas may have a more‐lasting positive effect and provide resources during droughts. Several Palearctic migrants were attracted to burned plots regardless of rainfall, which indicates continued fire suppression may threaten their already‐declining populations. Most notably, the paucity of birds observed on the controls suggests that the current structure of the matrix developed as a result of fire suppression. Traditional pastoralism appears critical to the maintenance of avian diversity in these savannas.     

Cost‐effective conservation of an endangered frog under uncertainty

How should managers choose among conservation options when resources are scarce and there is uncertainty regarding the effectiveness of actions? Well‐developed tools exist for prioritizing areas for one‐time and binary actions (e.g., protect vs. not protect), but methods for prioritizing incremental or ongoing actions (such as habitat creation and maintenance) remain uncommon. We devised an approach that combines metapopulation viability and cost‐effectiveness analyses to select among alternative conservation actions while accounting for uncertainty. In our study, cost‐effectiveness is the ratio between the benefit of an action and its economic cost, where benefit is the change in metapopulation viability. We applied the approach to the case of the endangered growling grass frog (Litoria raniformis), which is threatened by urban development. We extended a Bayesian model to predict metapopulation viability under 9 urbanization and management scenarios and incorporated the full probability distribution of possible outcomes for each scenario into the cost‐effectiveness analysis. This allowed us to discern between cost‐effective alternatives that were robust to uncertainty and those with a relatively high risk of failure. We found a relatively high risk of extinction following urbanization if the only action was reservation of core habitat; habitat creation actions performed better than enhancement actions; and cost‐effectiveness ranking changed depending on the consideration of uncertainty. Our results suggest that creation and maintenance of wetlands dedicated to L. raniformis is the only cost‐effective action likely to result in a sufficiently low risk of extinction. To our knowledge we are the first study to use Bayesian metapopulation viability analysis to explicitly incorporate parametric and demographic uncertainty into a cost‐effective evaluation of conservation actions. The approach offers guidance to decision makers aiming to achieve cost‐effective conservation under uncertainty.