A low degree of polymerization at pH = 6-7 results from the lower value of the polymerization degree for the anion than for the undissociated
Besides, OA could pass into bacterial cells and once inside the microorganisms cell change from undissociated
to dissociated form and suppress cell enzymes (decarboxylases and catalases) and nutrient transport systems .
Where H2A represents undissociated
ascorbic acid, HA- is the ascorbate monoanion, A-2 is the ascorbate dianion, [MG] is the total Methylene green, MGH+ is the monoprotonated form of methylene green, MGH+s is the singlet excited state of monoprotonated form of methylene green, MGH is the reduced form of methylene green, A is the dehydroascorbic acid, K1 and K2 is the dissociation constants of ascorbic acid, K3 is the formation constant for monoprotonated methylene green, and k is the rate constant for reduction of methylene green.
Biocidal and oxidizing activities of this compound increased with the formation of hypochlorous acid (HClO) in its undissociated
form when in pure aqueous solution (EMMANUEL et al., 2004).
forms of OA have the ability to pass through bacterial cell membrane where alkaline medium of bacterial cytoplasm dissociates OA resulting in production of H+ ions that decreases pH of cell.
hypochlorous acid (HOCl) is thought to be the active moiety which can undergo dissociation into the less microbicidal OCl- with increased pH38.
In the pH 5 solution, the tested coatings exhibited the highest corrosion resistance because of the presence of undissociated
water molecules that formed a protective passive film on the coating surface.
While pH value is 6, activated bentonite has more removal efficiency, as its particles have active sites with negative charges at relatively acidic pH and phenol is undissociated
. Hence, the dispersion interaction predominated.
Citric acid (E330) also increases the acidity of the food product thus increasing the effectiveness of sodium benzoate and potassium sorbate since a greater proportion of the acids is in undissociated
Failey, "The Activity coefficient of the undissociated
part of weak electrolytes," Chemical Reviews, vol.
We therefore speculated that the contraction was caused by the hydrogen bonding between the dissociated phenolate group and the undissociated
phenol group .