TABLE 1.

Rate of recovery of PV1 Sabin strain by elution solution under different pHs^a

Expt no.	pH	Prefiltration TCID50/100 μl	Elution TCID50/100 μl	Recovery rate (%)	Avg (%)
1	7.0	362	256	7.1
2	7.0	304	256	8.4	8.5
3	7.0	512	512	10.0
1	9.0	362	2,048	56.6
2	9.0	512	3,444	67.2	63.7
3	9.0	431	2,896	67.2

^aThe volume for prefiltration was 400 ml in all experiments, and the volume for elution was 40 ml in all experiments.