Increased sensitivity and reproducibility through signal averaging in ranges near an instrumental limit of detection (original) (raw)
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SAMPLE PREPARATION FOR TRACE ANALYSIS BY CHROMATOGRAPHIC METHODS
Journal of Liquid Chromatography & Related Technologies, 2010
& The determination of trace analytes in complex natural matrices often requires extensive sample extraction and preparation prior to chromatographic analysis. Correct sample preparation can reduce analysis time, sources of error, enhance sensitivity, and enable unequivocal identification, confirmation, and quantification. This overview considers general aspects on sample preparation techniques for trace analysis in various matrices. The discussed extraction=enrichment techniques cover classical methods, such as Soxhlet and liquid-liquid extractions along with more recently developed techniques like pressurized liquid extraction, liquid phase microextraction (LPME), accelerated microwave extraction, and ultrasound-assisted extraction. This overview also deals with more selective methodologies, such as solid phase extraction (SPE), solid phase microextraction (SPME), and stir bar sorptive extraction (SBSE). The adopted approach considers the equilibriums involved in each technique. The applicability of each technique in environmental, food, biological, and pharmaceutical analyses is discussed, particularly for the determination of trace organic compounds by chromatographic methods.
Talanta, 1979
In the reviewer's opinion there are too many books on chromatography and related methods. An earlier book edited by Mikel had numerous competitors. Each book should justify its existence. This new one does. It is not a second edition of the previous manual but a refreshingly modem book which within its wide range deals clearly and in reasonable depth with equipment and materials readily available in the West. The book describes not only the principles involved but gives examples of applications and how to select and improve methods. Chromatography is still partly an art, or skill, and a particularly attractive feature of this book is that the experience of the contributors is revealed in the way they deal with minor handling techniques, and with other, at first sight apparently trivial, matters all of which in fact largely determine whether or not a chromatographic method will be found to. be successful. The book is large and for many users should be on its own self-sufficient, but it is impossible, and in this field impractical and undesirable, for any text to seek to be comprehensive. Reference is made to specialist texts. The topics covered include theories of chromatographic and related methods, applications of partition, adsorption, ion-exchange, gel, affinity and gas chromatography and techniques of column, paper, thin-layer and other types of chromatography. There are chapters on electromigration and countercurrent distribution, and the book ends with a useful review of the literature and a list of United Kingdom suppliers of materials and equipment. The chapters vary in style and scope but overall the coverage is good. In such a large book it is not surprising that there are a few outdated terms and typographical errors. The historical introductions are interesting and well-balanced. The book is indeed what its predecessor claimed to be, namely a laboratory, or bench, manual and in that appropriate guise it will prove of considerable value for reference and browsing. It is an excellent guide through the jungle of competing techniques, chromatographic reagents and suppliers, and will be of some help in assisting in decisions about the most suitable commercially available equipment. Both the novice, and the already experienced worker, will benefit from the expertise displayed.
Determination of trace elements in biological fluids
Journal of Analytical Chemistry, 2011
Main approaches to the trace element analysis of biological fluids and problems appearing in this case are considered. The specific character of these approaches is illustrated by the examples of the analysis of real samples for various trace elements. The advantage of methods for the direct determination of trace ele ments in these samples is demonstrated.
Available options for the determination of ultra trace elements in pristine environments
2009
There are many key factors that require consideration when trying to successfully determine elemental concentrations at ultra-low levels. Some of these processes include: sample collection, preservation, preparation and the consideration of the choice of instrumental technique for analysis. These all must be taken into account in order to ensure the highest quality and accuracy of the resulting data. This paper will discuss some of the options available for advanced contamination control as well as analytical techniques available for reporting extremely low detection limits. Instrumentation such as high resolution inductively coupled plasma mass spectrometry (HR-ICPMS) and hydride generation atomic fluorescence spectrometry (HG-AFS) will be discussed. High resolution ICPMS coupled with a clean working environment and procedures has shown through experimental data that for baseline monitoring work, where samples are relatively free of interferences, that extremely low detection limit...
Fresenius Journal of Analytical Chemistry, 1997
The need to adapt the definition of traceability in the Metrological Dictionary of ISO to the growing use of this concept in Analytical Chemistry aroused the broader, more flexible proposal expounded in this paper which aims to be closer to the bench level. The traceability concept is addressed in a hierarchical manner by ranking the different notions to which the qualifier "traceable" applies (results, standards, equipment and samples) in such a way that it is compatible with the ISO definition. Relationships among them and with classical analytical properties are also exposed.
The mussel watch: Intercomparison of trace level constituent determinations
Environmental Toxicology and Chemistry, 1983
The US. National Mussel Watch Program initially used split-sample analyses for interlaboratory quality control purposes. These indicated the possibility of interlaboratory analytical discrepancies as well as problems in the split-sample technique itself. For the third year of the program, two mussel homogenates were produced to serve as intercomparison samplesone for metals and organics, the other for radionuclides. The results obtained using these homogenates are encouraging in that generally good agreement is seen among analyses done by several labs in diverse pollutant classes. We conclude from this experience that a quality-control program relying on the analysis of large homogeneous samples of the matrix being dealt with is an essential part of any extensive, multilaboratory analytical program.