Simultaneous Quantitation of Amino Acid Mixtures using Clustering Agents

A method that uses the abundances of large clusters formed in electrospray ionization to determine the solution-phase molar fractions of amino acids in multi-component mixtures is demonstrated. For solutions containing either four or 10 amino acids, the relative abundances of protonated molecules differed from their solution-phase molar fractions by up to 30-fold and 100-fold, respectively. For the four-component mixtures, the molar fractions determined from the abundances of larger clusters consisting of 19 or more molecules were within 25% of the solution-phase molar fractions, indicating that the abundances and compositions of these clusters reflect the relative concentrations of these amino acids in solution, and that ionization and detection biases are significantly reduced. Lower accuracy was obtained for the 10-component mixtures where values determined from the cluster abundances were typically within a factor of three of their solution molar fractions. The lower accuracy of this method with the more complex mixtures may be due to specific clustering effects owing to the heterogeneity as a result of significantly different physical properties of the components, or it may be the result of lower S/N for the more heterogeneous clusters and not including the low-abundance more highly heterogeneous clusters in this analysis. Although not as accurate as using traditional standards, this clustering method may find applications when suitable standards are not readily available

The role of ecosystems and their management in regulating climate, and soil, water and air quality

1. Ecosystems have a critical role in regulating climate, and soil, water and air quality, but management to change an ecosystem process in support of one regulating ecosystem service can either provide co-benefits to other services or can result in trade-offs. 2. We examine the role of ecosystems in delivering these regulating ecosystem services, using the UK as our case study region. We identify some of the main co-benefits and trade-offs of ecosystem management within, and across, the regulating services of climate regulation, and soil, water and air quality regulation, and where relevant, we also describe interactions with other ecosystem services. Our analysis clearly identifies the many important linkages between these different ecosystem services. 3. However, soil, water and air quality regulation are often governed by different legislation or are under the jurisdiction of different regulators, which can make optimal management difficult to identify and to implement. Policies and legislation addressing air, water and soil are sometimes disconnected, with no integrated overview of how these policies interact. This can lead to conflicting messages regarding the use and management of soil, water and air. Similarly, climate change legislation is separate from that aiming to protect and enhance soil, water and air quality, leading to further potential for policy conflict. 4. All regulating services, even if they are synergistic, may trade off against other ecosystem services. At a policy level, this may well be the biggest conflict. The fact that even individual regulating services comprise multiple and contrasting indicators (e.g. the various components of water quality such as nutrient levels, acidity, pathogens and sediments), adds to the complexity of the challenge. 5. Synthesis and applications. We conclude that although there are some good examples of integrated ecosystem management, some aspects of ecosystem management could be better coordinated to deliver multiple ecosystem services, and that an ecosystem services framework to assess co-benefits and trade-offs would help regulators, policy-makers and ecosystem managers to deliver more coherent ecosystem management strategies. In this way, an ecosystem services framework may improve the regulation of climate, and soil, water and air quality, even in the absence of economic valuation of the individual services