Task analysis technique advantages

It is possible to carry out a chromatographic separation, collect all, or selected, fractions and then, after removal of the majority of the volatile solvent, transfer the analyte to the mass spectrometer by using the conventional inlet (probe) for solid analytes. The direct coupling of the two techniques is advantageous in many respects, including the speed of analysis, the convenience, particularly for the analysis of multi-component mixtures, the reduced possibility of sample loss, the ability to carry out accurate quantitation using isotopically labelled internal standards, and the ability to carry out certain tasks, such as the evaluation of peak purity, which would not otherwise be possible. 

Not only is there a need for the characterization of raw bulk materials but also the requirement for process controled industrial production introduced new demands. This was particularly the case in the metals industry, where production of steel became dependent on the speed with which the composition of the molten steel during converter processes could be controlled. After World War 11 this task was efficiently dealt with by atomic spectrometry, where the development and knowledge gained about suitable electrical discharges for this task fostered the growth of atomic spectrometry. Indeed, arcs and sparks were soon shown to be of use for analyte ablation and excitation of solid materials. The arc thus became a standard tool for the semi-quantitative analysis of powdered samples whereas spark emission spectrometry became a decisive technique for the direct analysis of metal samples. Other reduced pressure discharges, as known from atomic physics, had been shown to be powerful radiation sources and the same developments could be observed as reliable laser sources become available. Both were found to offer special advantages particularly for materials characterization. 

One of the most important tasks of modem analytical chemistry is the analysis of foods, including fundamental aspects as food safety, quality, and authenticity. In the last decade, and especially in the last years, CE has also gained popularity in food analysis as an alternative to GC or HPLC because of the inherent characteristics/advantages of the technique in terms of analysis speed, efficiency, and low sample and reagent consumption (50-54). Table 6.3 shows... 

In the past 15 years, the use of microfluidic devices for chemical analysis has increased tremendously. Indeed, a broad range of chromatographic and electrophoretic separation methods have been implemented in microchips. However, for widespread utilization of microfabricated devices in analysis applications, particularly in the field of proteomics, further efforts are needed to develop simple fabrication techniques that achieve functional integration of multiple tasks in a single device. " In this section, we describe the fabrication of microdevices using sacrificial materials and discuss some of the advantages of this approach over conventional microfabrication methods. 

In Chapter 8 a leading expert in the detection of adulteration of oils and fats, Rossell, explains the economic advantages which tempt unscrupulous dealers to add cheap oils to high-value oils such as olive oil. He then describes a technique which he and his coworkers at Bristol have pioneered where stable carbon isotope ratio (SCIR) measurement has simplified the task of detecting adulteration. He compares sterol and fatty acid methyl ester analysis with SCIR and shows how clearly the latter detects maize oil. 

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