Concentration-time washing curve

Figure 1.15 Concentration-time washing curve Solute concraitration vs. time...

Detergent enzyme performance is often reported in the form of such dose-response curves. The performance increases dramatically at the beginning, but reaches a maximum levd at higher enzyme concentrations. The extent to which the enzyme is able to remove stains from the fabric depends on the detergent system, temperature, pH, washing time, wash load, etc. Enzyme wash performance varies between liquid and powder detergents and with the composition of the soiling (Fig. 6). 

The aim of experimental washing curve determinations is to gain a knowledge of the amount of wash liquor, number of wash ratios (W) and washing time (0 required to remove a given quantity of solute from a filter cake. It is usually necessary to calculate the amount of solute to be removed from a specification of the allowable solute concentration remaining in the cake at the end of the wash. When typical data are recorded, the results can be plotted in a number of ways as the ... 

At the end of the experiment the cake was removed from the apparatus and weighed, the mass was 412.7 g. To determine the residual quantity of salts, a 137 cm aliquot of distilled water was used to reslurry the cake. The resulhng suspension was filtered and analysis of the filtrate showed a concentration of (j) = 0.9 ppm. The reslurrying/filtration process was performed a fiorther three times with the filtrate being analysed each time to respectively give Thermal drying of the final cake yielded a mass of 276.0 g. Plot the wash curve for the experiment. 

Figure 10.1 represents batch washing. The average solute concentration in wash effluent at any time (or wash ratio) can be calculated from the washing curve using the following equation (if washing with a clean wash liquid) ... 

Procedure. A hexane solution of Compound 118 is diluted or concentrated so as to bring the 118 content within a range of 15 to 150 micrograms per ml. In cases where the hexane solution requires concentration, the evaporation is carried out in a beaker on a steam bath with a gentle stream of air passing over the surface. The concentrated or diluted solution of 118 is washed with hexane into a volumetric flask and made up to volume with the hexane washings. One milliliter of the adjusted Compound 118 solution is precisely measured into a spectrophotometer cell, 2 drops of phenyl azide are added, and the dihydrotriazole is quantitatively formed and then treated with diazotized dinitroaniline to produce the red color as in the preparation of the standard curve. A blank, starting with 1.0 ml. of hexane and 2 drops of azide, is run at the same time. 

The effects of a washing step on the position and shape of a breakthrough curve and the amount of protein retained in the column are shown in Fig. 37 using hen egg white lysozyme and Cibacron Blue F3GA immobilized Fractosil 1000 system as the exemplar. In Fig. 37a the time-concentration... 

FIGURE 37 The upper panel (a) shows the time concentration curves for the loading of a HPLC-BMC column (Cibacron Blue F3GA Fractosil 1000 with HEWL) to an effluent concentrations of 2, 20, and 99% of the influent concentration, respectively, followed by washing, (b) The lower panel shows the concentration profiles in the solid phase corresponding to the numbered times the upper for this protein-sorbent combination. Data adapted from Ref. 8. 

Turbidimetry indicated that precipitate formation depended on the concentration of the protein as well as on that of the polysaccharide, the time-period of incubation, and the ratio of protein to polysaccharide.121,359,360 Precipitin curves determined turbidimetrically differed from those determined by analysis of precipitated nitrogen.360 For these reasons, early turbidimetric studies conducted on crude (rather than purified) con A are difficult to interpret. The quantitative precipitin method, wherein increasing amounts of polysaccharide or glycoprotein are added to standard aliquots of con A, and the resulting precipitate is washed, and analyzed for nitrogen, is now considered the method of choice for studying protein-polysaccharide interaction.170,320... 

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