Proteins and the Theory of Colloidal Behavior (Paperback)

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1922 Excerpt: ...for the observed P.D. agree with the values of the calculated P.D. within the limits of accuracy of the measurements. This quantitative agreement between the observed P.D. and the P.D. calculated on the basis of the Donnan theory leaves little doubt that the observed P.D. is exclusively determined by the Donnan equilibrium. Hydrogen Ion And Chlorine Ion Potentials If we write the equation for the equilibrium condition between gelatin chloride solution and water in the form V = x x y ]z where x is the concentration of H and Cl ions in the outside solution, y the concentration of the H and Cl ions of the free HCl inside the gelatin chloride solution, and z the concentration of y the Cl ions in combination with the gelatin, -is the ratio of hydrogen ion concentration inside to the hydrogen ion concen tration outside: and--: --the ratio of the concentration of the y + z chlorine ion outside to the chlorine ion inside. Since, y log-= pH inside minus pH outside and x. log--j--= pCl outside minus pCl inside y + zit follows that pH inside minus pH outside = pCl outside minus pCl inside (2) If Donnan's membrane equilibrium is the cause of the influence of pH on the P.D. (and on the other physical properties) of protein solutions, we must be able to show that equation (2) is actually fulfilled. This consequence of Donnan's theory was put to a test and some of the experiments described in the preceding part of this chapter were selected for this purpose. Inside the collodion bags were 1 per cent solutions of gelatin chloride of different pH; outside, water. After 18 hours equilibrium was established between inside and outside solutions and the pCl as well as the pH was ascertained. The pCl was determined in two different ways in the two experiments; in one experiment it...