Sample Preparation:  Quo Vadis?

Abstract

The sample preparation step in an analytical process typically consists of an extraction procedure that results in the isolation and enrichment of components of interest from a sample matrix. Extraction can vary in degree of selectivity, speed, and convenience and depends not only on the approach and conditions used but on the geometric configurations of the extraction phase. Increased interest in sample preparation research has been generated by the introduction of nontraditional extraction technologies. These technologies address the need for reduction of solvent use, automation, and miniaturization and ultimately lead to on-site in situ and in vivo implementation. These extraction approaches are frequently easier to operate but provide optimization challenges. More fundamental knowledge is required by an analytical chemist not only about equilibrium conditions but, more importantly, about the kinetics of mass transfer in the extraction systems. Optimization of this extraction process enhances overall analysis. Proper design of the extraction devices and procedures facilitates convenient on-site implementation, integration with sampling, and separation/quantification, automation, or both. The key to rational choice, optimization, and design is an understanding of the fundamental principles governing mass transfer of analytes in multiphase systems. The objective of this perspective is to summarize the fundamental aspects of sample preparation and anticipate future developments and research needs.

Dynamic ultrasound-assisted extraction of polyphenols in tobacco

“…The analytes are then transported through the tobacco particle, eventually reaching the bulk of the extraction phase. This discussion is suitable for modeling the dynamic extraction, under the conditions of good solubility (k = 0), in which the sample is exposed to the static extraction phase for a time required to achieve equilibrium before fluid flowing [11]. The similar principle may be used to explain the process that the analytes were absorbed by support materials (celite), and then reextracted by extraction phase.…”

Extraction of Gaseous VOCs Using Passive Needle Trap Samplers

“…The relations of extracting VOCs mass and sampling flow rates were evaluated. Actually, the NTS has the potential to be used as a personal passive VOC sampler due to its small size for wearing by a worker for a long period, like a badgelike or penlike sampler (Pawliszyn, 2003;Gong et al, 2008). In order to assessing the feasibility of this self-designed DVB-NTS as a passive sampler for the working place, the long sampling periods of 4-12 hr was also examined.…”

Extraction of Drug from the Biological Matrix: A Review

“…Solid Phase Microextraction (SPME) (Pawliszyn et al, 1997;Pawliszyn, 1995Pawliszyn, , 1998Pawliszyn, , 1999Pawliszyn, , 2003Wercinski 1999) Miniaturization of sorbent technology and the concomitant decrease in solvent purchase, exposure and disposal has also taken a further giant step with the development of SPME. Solid-Phase Microextraction (SPME) is a very simple and efficient, solventless sample preparation method.…”