Resolution power

In analogy to the spatial resolution a temporal resolution power Rt can be defined ... 

The potential information amount Mpot of an analytical method is directly characterized by their signal resolution power (analytical resolution power) Rz = N... 

It must be also considered that the reaction rates of different thermal processes which can occur simultaneously are influenced by the treatment conditions (temperature, heating rate, pressure, static or dynamic atmosphere). This will affect the relative quantities of the products formed and in some cases also their nature, when recombination reactions give rise to secondary degradation products. On account of its sensitivity and resolution power Py-GC/MS will also provide useful information on minor components present in a material, including low molecular weight additives and pigments. 

The chemometricians tools and resolution power has a tremendous role to play in expanding and clarifying the information that we get. There is another side to the question and that is that it is critical for the analytical chemist to involve himself in helping understand the structure of the data. 

In this initial demonstration in the China Lake combustor, each control step required approximately 10 s, primarily due to the slow data transfer rate and computation of the (1-hertz resolution) power spectrum. Significantly faster response times may be obtained by using other algorithms to compute the magnitude of temperature fluctuations (e.g., a 3-kilohertz control response rate has been obtained at Stanford University [7]). Improved response... 

Once the chromatogr hic system has been selected, the problem reduces to the design of a column having the required resolution power while minimizing analysis time and possibly inlet pressure. Before discussing this problem we need to know the relationships between analysis time, flow velocity, and pressure, and between resolving,power and flow veloclly. 

HPLC analysis of food proteins and peptides can be performed for different purposes to characterize food, to detect frauds, to assess the severity of thermal treatments, etc. To detect and/or quantify protein and peptide components in foods, a number of different analytical techniques (chromatography, electrophoresis, mass spectrometry, immunology) have been used, either alone or in combination. The main advantages of HPLC analysis lie in its high resolution power and versatility. In a single chromatographic run, it is possible to obtain both the composition and the amount of the protein fraction and analysis can be automated. 

Compared to other HPLC techniques, RPC has a higher resolution power and allows protein analysis at low ionic strengths. On the other hand, it can be responsible for protein denaturation, loss of biological activity and interferences of hydrophobic contaminants [107]. 

Despite the low reproducibility and short life time of the NP columns, they are widely used owing to their better selectivity and resolution power, which enable the separation of (3- and y-isomers easily. The most used stationary phases are silica, aminopropyl- or diol-bonded [476], A more accurate description of the column used can be found in a review about tocol-derivatives analysis by Abidi [477], Kamal-Eldin et al. [478] compare the performance of new silica-type columns, six different silica columns, three amino columns, and one diol column. The new generation column results are much more repeatable and therefore suitable for vitamers analysis. 

When the step separation is wide enough, typical spiral step patterns observable by optical microscopy may appear, but if the separation becomes narrower than the resolution power of the optical microscope, the spirals appear in the forms of polygonal pyramids or conical growth hillocks. Even if spiral patterns are not directly observable, we may assume that these growth hillocks are formed by the spiral growth mechanism. Examples representing the two cases are compared in Fig. 5.8. 

The high resolution power provides for a good profile analysis of the sample with a clear pattern and minor peak overlap compared to packed column GC. Furthermore, in view of the possible toxic, synergestic or antagonistic effects of the individual PAH, it is important to quantify each compound separately. The chromatograms also demonstrate the application of 0V-73 to PAH analysis, a stationary phase similar to SE-52, but with improved temperature stability. 

The high resolution power allows good separation of critical isomers, like 1- and 2-aminonaphthalene and yields accurate results in quantitative work (Figure 4). 

Tests. A solution mixture of 0.02% v/v toluene in hexane (UV grade) is used to test the resolution power of the spectrophotometer. Hexane as the reference is scanned and then the spectrum of the resolution solution from 250 to 300 nm is obtained. The absorbance values of the Amax at 269 nm and the Amin at 266 nm are recorded (Figure 10.7). 

This type of instrument resembles a spectrograph because it allows the simultaneous measurement of all wavelengths. It uses an array of up to 2 000 miniaturised photodiodes (Fig. 11.13). A full spectrum can be recorded in milliseconds with this type of simultaneous acquisition detector, each diode measuring the light intensity over a small interval of wavelength. The resolution power of these diode-array spectrometers is limited (usually 1 to 2nm) by the size of the diodes. 

---