Typical analytical characteristics

Edible fats and oils vary considerably in the chemical composition which determines those physical characteristics that provide functionality. Physical, chemical, and performance analyses are the tools available to the fats and oils processor for the evaluation of existing products, development of new products, purchase of raw materials, and identification of specific customer requirements. Typical refined cottonseed oil analytical characteristics including fatty acid and triacylglycerol composition and ranges allowing for the different varieties, growing conditions, and analytical error are shown in Tables 7.1, 7.2 and 7.3. 

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It is important to note that wastewater is subject to great variability in terms of its components and processes. Procedures 1 to 4, therefore, correspond to a typical analytical method for the determination of the characteristic components and the stoichiometric and kinetic parameters. Cases where the procedure described in Sections 7.2.1-1.2 A is either difficult or not feasible to follow may exist. A detailed knowledge on wastewater characteristics and experience from laboratory and modeling studies may be crucial in such situations for finding alternative variants of the procedures 1 to 4. 

Typical analytical performance characteristics that should be considered in the validation of the types of procedures described in this chapter are listed below. Each validation characteristic is defined to ensure consistency in usage of terminology and interpretation ... 

Table 15 lists the typical cottonseed oil analytical characteristics, including fatty acid and triglyceride compositions and ranges (43, 80), which allow for the different varieties, growing conditions, and analytical error. 

A professional description of flavours uses as precise descriptors as possible. Chemical analytical results are combined with sensory analysis of the identified components to assess the relative importance and contribution to the flavour profile. Key ingredients or character impact compounds (CIC) are important components sine qua non to impart the typical, product characteristic, flavour, e.g. anethol for anise, eugenol for clove, 3-methyl butyl acetate for banana or ethyl butyrate to improve the juiciness of orange juice. 

Several characteristics of chromatography impact on the microdialysis experiment. The chromatography process inherently dilutes the sample. If we assume that a typical microdialysis experiment will involve a perfusion rate of 1 lL/min, with sampling for 5 min, 5 4L of sample will be obtained for the assay. A typical analytical column (15 cm X 4.6 mm) with a mobile-phase flow rate of 1 mL/min may have a peak width of 30 sec and would correspond to a 500-... 

Table 7.1 Typical refined cottonseed oil analytical characteristics...

Methods, (other than pharmacopoeial methods), should be validated. Typical validation characteristics which should be considered, include accuracy, precision, (repeatability and intermediate precision), specificity, detection limit, quantitation limit, linearity and range. Robustness should be considered at an appropriate stage in the development of an analytical procedure. 

The choice of an ionisation method depends on the analyte characteristics and the required type of analytical information. Classically, hard ionisation methods such as electron ionisation (El) or chemical ionisation (Cl) make use of their fragmentation capabilities to gain stractural information, typically of small organic molecules. In contrast, soft ionisation techniques such as electrospray ionisation or laser desorption are used to obtain mass spectra of intact molecules with little or no fragmentation, being capable of analysing complex multi-component mixtures. 

Method validation makes use of a set of tests that both test any assumptions on which the analytical method is based and establish and document the performance characteristics of a method, thereby demonstrating whether the method is fit for a particular analytical purpose. Typical performance characteristics of analytical methods are applicability, selectivity, calibration, trueness, precision, recovery, operating range, limit of quantification, limit of detection, sensitivity. 

In recent years more detailed models were developed. Liguras and Allen [1989] described the conversion of Vacuum Gas Oil in terms of a relatively large number of pseudo-components, most of which are lumps in their own way. Klein et al. [1991] generated these pseudo-components from analytical characteristics using Monte-Carlo simulation. Instead, Quann and Jaffe [1992, 1996] and Christensen et al. [1999] in their Structure Oriented Lumping (SOL) expressed the chemical transformations by accounting for typical structures of the various types of molecules, without completely eliminating lumps and because of that, rate parameters that still depend upon the feedstock composition. 

A typical envelope opening has a complicated shape and is often subject to unsteady flow conditions at its inlet and outlet.- There are no simple analytical solutions for the flow through such openings. The most-used equation representing flow characteristics is the so-called power law ... 

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