Effect of glutaraldehyde on the osmolarity of the buffer vehicle

Abstract

SUMMARY The osmolarity of four different buffers (Na‐cacodylate, PIPES, Na‐K‐phosphate and Na‐Na‐phosphate) at different pH‐values and molarities was measured. On the addition of glutaraldehyde to these buffers, an increase in osmolarity was observed. This increase was more than could be explained by the numerical addition of the osmolar values of the glutaraldehyde and of the buffer. The increase is due to a higher buffer dissociation constant. On the addition of 5% glutaraldehyde to a 0.05 M buffer, the increase in buffer osmolarity may be as much as 107 mOsm. Graphs are given to allow the determination of K‐values for these four buffers at different molarities and pH‐values. The effect of different glutaraldehyde concentrations on these K ‐values is presented graphically. The time‐dependent increase in osmolarity of glutaraldehyde solutions in water is described.