TFF & Diafiltration Calculator
Calculate TFF VCF, concentration, recovery, flux, and TMP plus constant-volume diafiltration DV and buffer exchange.
Enter both area/time for flux and all three pressures for TMP. Use the same pressure unit.
Results
Enter initial/final volume and initial concentration.
The theoretical concentration assumes complete product retention and no loss, hold-up, sampling, or adsorption. Observed recovery and flux/TMP are arithmetic summaries; they do not recommend a membrane or operating setpoint.
Basis: Merck TFF definitions for VCF and DV, TMP=[(Pfeed+Pretentate)/2]−Ppermeate, and continuous-DF C/C0=exp[−(1−R)N].
Tool Guide
Definition
TFF & Diafiltration Calculator — Calculates VCF, mass-conservation concentration, observed recovery, permeate flux, and TMP for TFF concentration. Constant-volume DF converts buffer volume to DV and predicts ideal remaining solute and target DV using microsolute retention.
Purpose
(1) Cross-check pre/post concentration volume and concentration, (2) calculate observed product recovery, (3) record average flux and TMP, and (4) estimate DF buffer needs and ideal impurity washout.
How to Use
① Enter initial/final retentate volume and initial concentration in TFF mode. ② Add observed final concentration for recovery and both membrane area/time for LMH. ③ Enter feed, retentate, and permeate pressures in the same unit for TMP. ④ In DF mode enter constant retentate volume, buffer volume, microsolute retention R, and optionally a target remaining percent. Confirm model assumptions experimentally.
Examples
Example) Concentrating 10 L at 4 g/L to 2 L gives VCF=5× and a loss-free theoretical concentration of 20 g/L. An observed 18 g/L gives 90% recovery. For constant-volume DF with 2 L retentate, 10 L buffer, and R=0, 5 DV predicts 0.6738% remaining and 99.3262% removed.