Unique 96-well equilibrium dialysis block with novel vertical alignment of dialysis membrane. Dispense and aspirate from both sample and dialysate side. Analyze a large number of samples, time points, or replicates in the same experiment. Add or remove samples individually or simultaneously. The exclusive design eliminates problems associated with trapped air pockets. Maximizes ratio of dialysis membrane surface area to volume. Compatible with most standard 96-well format laboratory supplies and instruments. Permits robotic systems to access both the sample and dialysate sides of the dialysis so assays can be readily automated. Reusable, easily assembled and can be shaken in controlled temperature environments. Teflon construction minimizes non-specific binding of test samples.