Will the Digital Mass Filter Be the Next High-Resolution High-Mass Analyzer?

Mass filter operation in higher stability zones is known to provide better resolution. Unfortunately, for sine driven instruments, higher stability zone operation reduces the accessible mass range and increases the degenerative effects of fringe fields. Conversely, digitally driven mass filters do not suffer from loss of mass range, and the fringe field effects do not increase significantly by switching stability zones because the AC voltage is always constant and the DC voltage is always zero. This work catalogues 12 stability zones that are accessible with the new digital waveform generation technology. These zones have theoretical baseline resolving powers that range from 22 to 1 300 000 with pseudopotential well depths that range from 3.5 to 43 V. Operation in higher stability zones also has the advantage of aligned axial stability wells. That alignment maximizes the pseudopotential well depth for each higher stability zone, making them more than an order of magnitude greater than the standard ∼0.2 V well of a sine filter operating in the first stability zone at unit resolution. Increased pseudopotential well depth correlates with better ion transmission and sensitivity. Our theoretical examination suggests that the digital mass filter can obtain both high resolution and high sensitivity with essentially unlimited mass range.

Integration of mass spectral fingerprinting analysis with precursor ion (MS1) quantification for the characterisation of botanical extracts: application to extracts of Centella asiatica (L.) Urban.

INTRODUCTION: The phytochemical composition of plant material governs the bioactivity and potential health benefits as well as the outcomes and reproducibility of laboratory studies and clinical trials. OBJECTIVE: The objective of this work was to develop an efficient method for the in-depth characterisation of plant extracts and quantification of marker compounds that can be potentially used for subsequent product integrity studies. Centella asiatica (L.) Urb., an Ayurvedic herb with potential applications in enhancing mental health and cognitive function, was used as a case study. METHODS: A quadrupole time-of-flight analyser in conjunction with an optimised high-performance liquid chromatography (HPLC) separation was used for in-depth untargeted fingerprinting and post-acquisition precursor ion quantification to determine levels of distinct phytochemicals in various C. asiatica extracts. RESULTS: We demonstrate the utility of this workflow for the characterisation of extracts of C. asiatica. This integrated workflow allowed the identification or tentative identification of 117 compounds, chemically interconnected based on Tanimoto chemical similarity, and the accurate quantification of 24 phytochemicals commonly found in C. asiatica extracts. CONCLUSION: We report a phytochemical analysis method combining liquid chromatography, high resolution mass spectral data acquisition, and post-acquisition interrogation that allows chemical fingerprints of botanicals to be obtained in conjunction with accurate quantification of distinct phytochemicals. The variability in the composition of specialised metabolites across different C. asiatica accessions was substantial, demonstrating that detailed characterisation of plant extracts is a prerequisite for reproducible use in laboratory studies, clinical trials and safe consumption. The methodological approach is generally applicable to other botanical products.

Interrogating Social Sustainability in the Biofuels Sector in Latin America: Tensions Between Global Standards and Local Experiences in Mexico, Brazil, and Colombia.

Across the Americas, biofuels production systems are diverse due to geographic conditions, historical patterns of land tenure, different land use patterns, government policy frameworks, and relations between the national state and civil society, all of which shape the role that biofuels play in individual nations. Although many national governments throughout the Americas continue to incentivize growth of the biofuels industry, one key challenge for biofuels sustainability has been concern about its social impacts. In this article, we discuss some of the key social issues and tensions related to the recent expansion of biofuels production in Mexico, Colombia, and Brazil. We argue that a process of "simplification" of ecological and cultural diversity has aided the expansion of the biofuels frontier in these countries, but is also undermining their viability. We consider the ability of governments and non-state actors in multi-stakeholder initiatives (MSI) to address social and environmental concerns that affect rural livelihoods as a result of biofuels expansion. We analyze the tensions between global sustainability standards, national level policies for biofuels development, and local level impacts and visions of sustainability. We find that both government and MSI efforts to address sustainability concerns have limited impact, and recommend greater incorporation of local needs and expertise to improve governance.

Contingencies affecting emergency preparedness for hazardous wastes

Through a case study of emergency preparedness activities at the largest hazardous waste landfill within the United States, which is located in Sumter County, Alabama, this article highlights three features which constrain such preparedness efforts: (1)the specialized nature of hazardous waste; (2)the politicization of the hazardous waste industry; and (3)jurisdictional dilemmas created by the merger of public and private roles in hazardous waste emergency preparedness. The article concludes with a discussion of policy implications for federal, state and local policymakers and implementers.(AU)