Principles of Sampling

The principle of sampling suggested in the previous paragraph can begesner-alized in the form... 

For the quantitation of chromatograms, the development condition found by the conventional TLC was transferred to another TLC system which uses a thin quartz rod coated with silica gel of 75 p thickness and may be called thin-layer-FID chromatography . The TLC system is equipped with a flame ionization detector (FID) and commercially available as a complete set (Iatron thinchrograph model TFG-10, Iatron Co., Ltd., Tokyo). The principle of sample scanning and device for FID are almost the same as those worked out by Padley57), Szakasits et al, and... 

Benedetti-Pichler, A. A. Theory and Principles of Sampling for Chemical Analysis. In Ed. W. G. Berl, Physical Methods in Chemical Analysis, Vol. III. New York Academic Press 1956. 

Principles of sampling for threshold control are described by KATEMAN and PIJPERS [1981]. The authors show that the sampling frequency depends on the distance between the last value measured and the threshold level. They explain both the adaptation of the sampling frequency to the existing state of the process or the environmental compartment under control, and the effect of the distance between samples on the cost of the project. 

A sensor based on the same principle of sample degassing in a void volume but mounted completely inside the reactor (Foxboro/Cerex Fig. 14) has been described by Hopkins and Hatch [178]. The minimal time interval between individual measurements is 30 s. Both 90° scatter and transmission measurements can be made simultaneously. A linear correlation between OD and Saccharo-myces cerevisiae density from 0.1 to 150 g 1 1 has been claimed for this instrument [152]. 

The microdialysis technique can be used for continuous in vivo sampling of any body fluid. The main application field of microdialysis is for monitoring the intercellular chemical signaling and transport of molecules in the extracellular fluid. The principle of sampling, based entirely on dialysis (diffusion), ensures that no fluid is removed from or delivered into the sampling area. This principle, together with a fine diameter of the microdialysis cannula, makes it... 

Parameter Type of Main Main Principle of Sampling Precision Range Possible Examples of... 

The principle of sample spinning has been described in Section 3.3.3. As a result of sample spinning, the interaction Hamiltonian and thus the resonance frequency (cf. eqn (3.3.6)) becomes time dependent. For the simple case of a pair ij of dipolar coupled spins i, equivalent to a quadrupolar nucleus spin 1 like with, the time-dependent spin Hamiltonian is given by [Mehl, Schl]... 

To understand the principles of sampling soil and sediment, water and air. 

E. A. Houser, Principles of sample handling and sampling system design for process analysis, Instrument Society of America, Pittsburgh, 1972. 

So far, two principles of sampling have been applied in high-performance LC (HPLC) syringe and valve injection. Both types, conmercially available or custom-made, are discussed in detail below. 

It is important to understand the principles of sampling and be aware of the precautions that are necessary to obtain a representative laboratory sample. Definitions of the terms increment, sample, spot sample, composite sample and laboratory sample are given in the Glossary. Figure 6.1 illustrates how they are related. 

Houser, E. A. Principles of Sample Handling and Sample Systems Design for Process Analysis. Pittsburgh Instrument Society of America, 1972. Contains good information on the design of sample-handling systems. 

Fig. 7-3. The principle of sample preparation by solid phase extraction (SPE)...

In this chapter, we will discuss the basis of sample preparation for five of the six categories listed above and focus on the determinative step for all six in Chapter 4. Total organic carbon commonly called TOC is a combustion technology in which aqueous samples can be injected directly without the need for sample preparation therefore, we will not discuss it any further in this chapter. Let us start with a discussion of the principles of sample prep with respeet to trace metals. 

In this article, the principles of sample preparation and measurement of the catalytic concentration of enzymes of clinical importance and of the absolute enzyme concentration are discussed. 

Figure 5 Schematic diagram of the principle of sample stacking in CZE (A) and MEKC (B).

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