Other attributes

Percoll consists of silica particles (15 to 30 nm diameter) coated with non-dialyzable polyvinylpyrrolidone (PVP). Free PVP is present at only 1% to 2%. Percoll is non-toxic, almost chemically inert and does not adhere to membranes. Percoll gradients can be formed within the density range of 1.0 to 1.3 g/mL, and are iso-osmotic throughout.

Percoll can be stored unopened at room temperature for five years. At -20°C, it can only be stored for up to six months.

If stored at -20°C, gradients form upon thawing, necessitating a mixing of the bottle before use. Preformed gradients can be stored for weeks without a change in gradient shape, provided that the gradient remains unfrozen.

Percoll can be buffered within the pH range 5.5 to 10.0 without any changes in properties. If pH drops below 5.5, gelling may occur. Gelling can also be caused by the presence of divalent cations, an effect which is exacerbated by elevated temperatures.

Undiluted Percoll can be resterilized by autoclaving for 30 min at 120°C.