Analysis methods hyphenated chromatographic techniques

It is generally difficult to identify developments with high potential where interferences do not preclude general application. To ensure the relevance of a method, its application to real sample analysis must be demonstrated. The accuracy of an analytical method should be confirmed by an independent method, or by the analysis of certified reference materials. Detailed comparative studies of the method developed with other well-established methods for polymer/additive analysis are not frequent in the analytical literature. Nevertheless, some examples may be found in Section 3.6. Improvements in analytical techniques are reasonably sought in sample preparation and in hyphenated chromatographic techniques. However, greatest efficiency is often gained from the use of databases rather than accelerated extraction or hyphenation. 

Even though, there is no cookbook for HPLC method development this book provides several strategies that the reader could use when presented with a particular situation. These strategies could be stored as tools in the scientists method development arsenal, and drawn from when needed to tackle a particular separation. Moreover, some novel approaches for implementing HPLC, fast HPLC, and hyphenated HPLC techniques towards pharmaceutical analysis are discussed. This book has the potential to serve as a useful resource for the chromatographic community. It can be used as a handbook for the novice as well as the more experienced pharmaceutical chemist who utilizes HPLC as an analytical tool to solve challenging problems regularly in the pharmaceutical industry. 

In pharmaceutical analysis the detection of impurities under a chromatographic peak is a major issue. An important step forward in the assessment of peak purity was the introduction of hyphenated techniques. When selecting a method to perform a purity check, one has the choice between a global method which considers a whole peak cluster (from the start to the end of the peak), and evolutionary methods, which consider a window of the peak cluster, which is... 

Principles and Characteristics Extraction or dissolution methods are usually followed by a separation technique prior to subsequent analysis or detection. While coupling of a sample preparation and a chromatographic separation technique is well established (Section 7.1), hyphenation to spectroscopic analysis is more novel and limited. By elimination of the chromatographic column from the sequence precol-umn-column-postcolumn, essentially a chemical sensor remains which ensures short total analysis times (1-2 min). Examples are headspace analysis via a sampling valve or direct injection of vapours into a mass spectrometer (TD-MS see also Section 6.4). In... 

In a typical analysis, one approach would be to carry out the analysis by first using Cl and quadrupole MS. The fragments from this first MS would then be directed to an El and a TOF mass spectrometer. Different fragments will be observed and this will yield additional information about the sample. In many cases, the MS-MS analysis is applied to samples eluting from either LC, HPLC, or GC chromatographic separation techniques. For additional information on this topic, see Triple Hyphenated Methods. ... 

Methods for the analysis of organic and organometallic compounds are discussed in this chapter. It has become evident that for the analysis of these two classes of compounds, the analyst can draw on a very similar repertoire of analytical techniques with respect to sample preparation, separation, and detection. Chromatographic and, in particular, hyphenated techniques are the workhorses of environmental water analysis. The various formats and technical realizations of mass spectrometers are the most versatile detectors. Their sensitivity and ability to provide structural information at the low and even sub-pg level are an asset and at the same time a prerequisite for (ultra)trace analysis in the aquatic environment. As further significant improvements in detector sensitivity are unlikely, the probable focus of attention in the future will again be on sample preparation. Here, the introduction of new approaches, techniques, and materials for sample preparation can be expected to make a significant impact in this field. 

Whenever the goals of curve resolution are achieved, the understanding of a chemical system is dramatically increased and facilitated, avoiding the use of enhanced and much more costly experimental techniques. Through multivariate-resolution methods, the ubiquitous mixture analysis problem in chemistry (and other scientific fields) is solved directly by mathematical and software tools instead of using costly analytical chemistry and instrumental tools, for example, as in sophisticated hyphenated mass spectrometry-chromatographic methods. 

The nutritional, chemical, biological, and toxicological properties of a chemical element are known to be critically dependent on the form in which it occurs in food. The recognition of this fact has spurred the development of species-selective (speciation) analytical methods for food additives and contaminants. According to the IUPAC s dehnition, speciation analysis deals with the analytical activities of identification and/or measurement of the quantities of one or more individual chemical species in a given sample [1], The analytical approach is usually based on the combination of a chromatographic separation technique with an element-specif>c detection technique. The former ensures that the analyte compound leaves the column unaccompanied by other species of the analyte element, whereas the latter enables a sensitive and specil>c detection of the target element. Coupled (also called hyphenated) techniques have become a fundamental tool for speciation analysis and have been discussed in many published reviews [2D6]. 

A strong preference in speciation analysis is to use a separation step that can be combined with a detection step in an on-line system [45]. In such coupling, analytical selectivity relies on the application of different chromatographic or electrophoretic methods, while the use of atomic spectrometric techniques assures high sensitivity and f>t-for-purpose limits of detection (LoDs). However, hyphenated techniques with element-specif>c detection do not provide structural information on the species. If appropriate standards are available, the assignation of chromatographic peaks can be accomplished by spiking experiments. On the... 

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