Transporter continued sample analysis

Flow injection analysis (FIA) was developed in the mid-1970s as a highly efficient technique for the automated analyses of samples. °> Unlike the centrifugal analyzer described earlier in this chapter, in which samples are simultaneously analyzed in batches of limited size, FIA allows for the rapid, sequential analysis of an unlimited number of samples. FIA is one member of a class of techniques called continuous-flow analyzers, in which samples are introduced sequentially at regular intervals into a liquid carrier stream that transports the samples to the detector. ... 

FTA [5-7] is a version of continuous-flow analysis based on a nonsegmented flowing stream into which highly reproducible volumes of sample are injected, carried through the manifold, and subjected to one or more chemical or biochemical reactions and/or separation processes. Finally, as the stream transports the Anal solution, it passes through a flow cell where a detector is used to monitor a property of the solution that is related to the concentration of the analyte as a... 

Flow injection analysis (FIA), which was introduced by Ruzicka and Hansen (iz ) and by Stewart et al (iQ), is based on the concept of controlled dispersion of a sample zone when injected into a moving and nonsegmented carrier stream. In continuous flow analysis (CFA), successive samples are mixed and Incubated with reagents on the way toward a flow through detector. The greatest difficulty to overcome in CFA was intermixing of adjacent samples during transport from the injection valve to the detector. In the past, it was widely believed that there are only two ways to prevent carryover in CFA either by the use of turbulent flow or by air... 

Flow injection analysis (FIA) is based on the injection of a known amount of sample in a flowing carrier solution stream via an injection valve (IV) the flowing carrier transports the sample to the detector. The main advantages of FIA compared with continuous flow systems are the operational simplicity and the lower consumption of sample and carrier (Bryce et al., 1995). However, the reduction in the amount of analyte deposited on the electrode surface as a result of the decrease in the contact time between the sample and the working electrode and the disprersion of the sample in the flow manifold results in a decrease of the analytical signal. A typical FIA system is illustrated in Fig. 3. 

The first sample to be analyzed is the field blank. If its spike recovery is unacceptable, indicating that a systematic error is present, then a laboratory method blank. Dp, is prepared and analyzed. If the spike recovery for the method blank is also unsatisfactory, then the systematic error originated in the laboratory. An acceptable spike recovery for the method blank, however, indicates that the systematic error occurred in the field or during transport to the laboratory. Systematic errors in the laboratory can be corrected, and the analysis continued. Any systematic errors occurring in the field, however, cast uncertainty on the quality of the samples, making it necessary to collect new samples. 

Mobile, on-line XRF methods have been tested in the Au exploration targets. Analysis of continuous till and weathered bedrock samples shows clear variation of the contents of pathfinder elements of hydrothermal alteration. Particularly, in the weathered bedrock, the presence of narrow mineralized veins is seen (Fig. 5). One interesting feature is that the indication of the weathered bedrock sources can be traced 2 to 5 m down-ice in the till. These results suggest very short glacial transport of mineralized debris from the bedrock sources. Information on... 

This Second Edition continues the basic approach of the first with the addition of four chapters. Chapter 1 is an outline of the development of soil chemistry with specific reference to the development of instruments that have been essential to the present understanding of soil chemistry. Chapter 7 is a new chapter dealing with soil sampling, both in the field and in the laboratory, soil water sampling, sample transport, and storage. Chapter 8 discusses direct, modified, and indirect methods of soil analysis. Chapter 15 covers the recent development of hyphenated instrumental methods and their application to soil analysis. 

Dead time. Probably the best example of a measurement device that exhibits pure dead time (time delay) is the chromatograph, because the analysis is not available for some time after a sample is injected. Additional dead time results from the transportation lag within the sample system. Even continuous analyzer installations can exhibit dead time from the sample system. 

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