INDEX dilution factor

The calculations are done in whichever transformation is necessary to allow parallel straight lines to be fitted. The estimation of potency from the vertical distance between the line requires also an index of slope for the portion of the curve being employed, which is given by the difference between the high and low responses of the two lines, divided by the log distance between the dilutions tested. This distance is the log of the dilution factor when serial dilutions are employed, e.g., log 2 for a series of 2-fold dilutions, log 4 for a 4-fold series. The estimate of potency is obtained from the ratio of the difference between patient and control readings to the slope of the lines (see below). 

In flow injection analysis, the first index proposed for this purpose was the dilution factor, D [7], further defined as "the ratio of concentrations before and after the dispersion process has taken place in the element of fluid that yields the analytical readout" [114]. This index has also been called dispersion number, dispersion D, dispersion value, dilution ratio and dispersion coefficient [115], and the latter term has been generally accepted. Its reciprocal was called the dispersion factor [116]. The dispersion coefficient also holds for flow injection systems with reagent injection into the flowing sample [117]. 

Besides other factors such as color and firmness, soluble solids to acids ratio is a good index to determine harvest time. For prunes, this value has to be 12-15 [13]. A maximum limit was set for citric acid to isocitric acid ratio to reveal the dilution factor of juices 130 for apricot puree and orange juice, 80 for grapefruit juice, and 185 for raspberry juice [14]. The total add content varies widely from <0.2% in papaya and avocado [3] to 8.3% in lemon juice [15]. 

The total polyphenol index is obtained by diluting the wine and measuring its absorbance at 280 nm. The index is given as the absorbance multiplied by the dilution factor (100 in the case of red wines). This test does not take into account the colorless chalcone forms of anthocyanins (Figure 3) nor the phenolic acids that absorb at 230 nm, though these compounds are present in such small quantities that they contribute little to the overall polyphenol content. 

Since we are taking NADPH as an index of glucose concentration, the above is also the concentration of glucose in the final solution. For finding out the concentration of glucose in the original solution, we will have to take into cognizance the dilution factor. 

An old method of measuring the degree of jaundice which consists of assessing the intensity of the yellow colour of the serum. The serum is diluted until it matches the colour of a 1 in 10 000 solution of potassium dichromate. The dilution factor is termed the icteric index. 

Odorant Odor quality Kovats index (DB-Wax) Flavor dilution factor... 

Sample preparation, injection, calibration, and data collection, must be automated for process analysis. Methods used for flow injection analysis (FLA) are also useful for reliable sampling for process LC systems.1 Dynamic dilution is a technique that is used extensively in FIA.13 In this technique, sample from a loop or slot of a valve is diluted as it is transferred to a HPLC injection valve for analysis. As the diluted sample plug passes through the HPLC valve it is switched and the sample is injected onto the HPLC column for separation. The sample transfer time typically is determined with a refractive index detector and valve switching, which can be controlled by an integrator or computer. The transfer time is very reproducible. Calibration is typically done by external standardization using normalization by response factor. Internal standardization has also been used. To detect upsets or for process optimization, absolute numbers are not always needed. An alternative to... 

The preceding discussion assumed a pure liquid was used for the measurement. Most molecules of interest, however, are not in the liquid state at room temperature. In this case it is common to dissolve the compound in an appropriate solvent and conduct the measurement. Contributions to the second harmonic signal are therefore obtained from both the solvent and solute. Since r and the local field factors that are related to e and n, (the dielectric constant and refractive index respectively) are concentration dependent, the determination of p for mixtures is not straightforward. Singer and Garito (15) have developed methods for obtaining r0, eQ, and nQ, the values of the above quantities at infinite dilution, from which accurate values for p can be obtained in most cases. 

The separation factor is a useful index describing the differential accumulation of two components in two well-defined regions. It is applicable whether the components are dilute or concentrated. However, it is specific to each component pair by differing in value from pair to pair it provides minimal information about the global capabilities of the separation step. 

The retention factor, Eq. (7.2), for each species / is calculated knowing the dead time, t(), and the retention time of species i at infinite dilution, /r,./- There are known methods in the literature for calculating the dead time or retention time for a non-retained peak in normal-phase, reversed-phase and ion-exchange chromatography [67]. For example, in normal-phase chromatography, pentane in 95 5 hexane-acetone is unretained. In reversed-phase chromatography, a common measure of void volume is from the refractive index response obtained when the sample solvent composition is different from the mobile-phase composition. 

Beyond the equivalence point the ratio of acid to alkaline forms of the indicator is proportional to the concentration of excess perchloric add. Thus, upon 10-fold dilution the color ratio decreases 10-fold, while the hydrogen ion concentration decreases by a factor of -s/lO. Again, the indicator color is not a straightforward index of acidity. 

An application of continuum solvation calculations that has not been extensively studied is the effect of temperature. A straightforward way to determine the solvation free energy at different temperatures is to use the known temperature dependence of the solvent properties (dielectric constant, ionization potential, refractive index, and density of the solvent) and do an ab initio solvation calculation at each temperature. Elcock and McCammon (1997) studied the solvation of amino acids in water from 5 to 100°C and found that the scale factor a should increase with temperature to describe correctly the temperature dependence of the solvation free energy. Tawa and Pratt (1995) examined the equilibrium ionization of liquid water and drew similar conclusions. An alternative way to study temperature effect is through the enthalpy of solvation. The temperature dependence of is related to the partial molar excess enthalpy at infinite dilution,... 

The influence of temperature on the mean dipole moment of polybutyl methacrylate dissolved in carbon tetrachloride is shown in Table II. The average moments were calculated from Frohlich s equation (see Section VI) taking unity as the most probable value of the correlation factor. Since the Onsager theory makes use of the refractive index of the solute, for which only approximate values can be found, results obtained by Onsager s and FrOhlich s theories for solutions are not identical even in a nonpolar solvent like carbon tetrachloride. The moments given in Table II are not comparable to those given in Table I, especially as they are not extrapolated to infinite dilution. 

Relatively few theoretical studies have been devoted to the conformational characteristics of nonlinear block copolymers in different solvent environments. Burchard and coworkers [284] studied theoretically the behavior of the static and dynamic structure factors for regular star-block copolymers in dilute solutions. They considered different cases where the refractive index (n)s of the solvent takes certain values with respect to the corresponding refractive indices of the inner and outer blocks. A different dependence of the ratios... 

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