Abstract
This review examines, from a critical point-of-view, the role of the separation sciences in the new century considering the complexity of the problems to be faced. To make the exposition more dynamic the determination of a typical (hypothetical) organic analyte in a complex matrix is used to critically introduce the major separation techniques used nowadays. Techniques that promote the reduction or that fully eliminate the use of toxic solvents are stressed. After this evaluation the author discusses the future trends in this area with emphasis on the miniaturization of the instrumental techniques, the full automation of the analyses, the use of hyphenated techniques, the under-explored role of the solvents in separation techniques, the development of transition phase chromatography and unified chromatography.
Highlights
During the last half of the 20th Century a tremendous growth in the demand for more complex analytical separations was observed
The basic instrument consists of a fluid reservoir, a system to pressurize the fluid to the desired value, an oven to control the temperature of the extraction cell where the sample is loaded, a restrictor to maintain the supercritical pressure inside the system and to control the fluid flow rate, and a collection vessel
The bar is introduced into the sample, which is stirred for a defined time to allow the transfer of the sample from the liquid matrix to the solid bar
Summary
During the last half of the 20th Century a tremendous growth in the demand for more complex analytical separations was observed. Soil sampling requires additional concerns, such as determination of the soil composition, sampling depth, and sampling length, weight, among other parameters After this step the actual analytical step starts with the so-called sample preparation step. Since this step differs considerably if one is dealing with organic or inorganic analytes, in this paper we will focus our examples on the analysis of organic compounds present in minute quantities in a sample. The major goal of the sample preparation step (Figure1) is to isolate the target compound(s) from the bulk matrix, facilitating the step that the analyte(s) determination. Further purification of the extract is required before the analyte(s)
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