How and why do you measure the pH of your silica gels?
This pH test involves suspending the silica gel in pure water (5 % w/w).
The pH can increase the retention of some ionizable compounds. However, some products can become hydrolyzed or rearranged when in contact with acidic silica. A neutral pH, with a range between 6.5 and 7.5, is the most important factor in determining the reliability and inert behavior of the silica.