Outline
- Abstract
- Keywords
- 1. the Green Wave
- 2. Greening Analytical Procedures
- 3. Facing the Problem of Sample Treatment
- 4. Green Extraction Solutions
- 5. Future Trends in Green Extraction
- Acknowledgements
- References
رئوس مطالب
- چکیده
- کلید واژه ها
- 1. موج سبز
- 2. روش های تجزیه ای سبز
- 3. مواجهه با مسئله درمان نمونه
- 4. محلول های استخراج سبز
- 5. روندهای آینده در استخراج سبز
Abstract
Greening extraction techniques to improve the sensitivity and the selectivity of analytical methods is the sustainable alternative to classical sample-preparation procedures used in the past. In this update, we review the main strategies employed in the scientific literature to reduce deleterious side-effects of extraction techniques. We demonstrate that the evolution of sample-treatment procedures is focused on the simultaneous improvement of the main analytical features of the method and its practical aspects, including the economic case.
Future trends in green extraction
Pioneering efforts in the automation of extraction procedures through FIA have been demonstrated to be one of the best ways to reduce operator risks and to avoid environmental side-effects by reducing consumption of reagents and generation of waste. However, the microscale of FIA procedures was not enough to assure their sustainability. Additional efforts in recent years on miniaturization of extraction also offered an interesting way to improve the greenness of analytical procedures. Recent developments on microfluidic systems [76] and on-chip µSPE include the use of disposable sorbents using mesofluidic platforms [77], which open new possibilities to green analytical methodologies. So, it is clear that in the years ahead much more effort will be made to link these approaches, which can also be improved by clever selection of the phases, solvents and solid, employed in the preconcentration steps to guarantee the inert character of residues and to consume as little energy as possible.
One of the key factors in evaluating the sustainability of the different methodologies proposed concerns the correct evaluation of environmental risks regarding reagents, wastes and the energy employed. Those factors must be balanced in order to provide simultaneously the best analytical features and the smallest environmental side-effects. As indicated previously [78], the greenest methodology is that suitable to solve an analytical problem with the minimum environmental impact, but stress must be placed on the first part of this sentence – finding the solution to the problem.
Concerning the reagents used in the extraction steps, efforts should also be made in evaluating new solvents (e.g., agro-solvents, ionic liquids or surfactant solutions), other organized media {e.g., crown [79] and crypta ethers, and calixarenes) and lipidic structures (e.g., liposomes and vesicles). The development of new solid phases suitable for use in the selective extraction of target analytes {e.g., imprinting solid phases [80] and nano-materials [81–83]} will contribute to improving the analytical features of the methods and to reducing dramatically the amounts of reagents and energy used. So, we must be optimistic about the future, and, once again, it will be demonstrated that GAC can be a driving force to expand basic research in analytical chemistry, to make an ethical commitment to the environment and to reduce the cost of the analytical methods, thereby contributing to the sustainability of laboratories and enterprises.