Supersaturation Ratio and Relative Excess: Preserve the Definition

Define the Phase or Process Boundary

METTLER TOLEDO's supersaturation explanation compares actual dissolved concentration C with equilibrium solubility C* at the same state. Here define ratio S=C/C*, relative excess σ=(C−C*)/C* and dimensional difference ΔC=C−C*. These are linked but are different reported quantities.

Review a Hypothetical Comparison

For a fictional trial, C=0.132 kg solute/kg solvent and C*=0.120 kg solute/kg solvent. Then S=1.10, σ=0.10 and ΔC=0.012 kg/kg. A note saying supersaturation 10% could refer to the relative excess; writing S=0.10 would instead place the ratio below saturation. A second report using solute per total solution mass needs a basis conversion before its numbers can be compared with these solvent-based concentrations.

Keep the Evidence with the Decision

Print the chosen definition beside every graph axis and worksheet entry. Match equilibrium solubility to the actual solvent mixture and temperature. Preserve whether concentration is measured, inferred or modelled. Compare like definitions before attributing a changed crystal population to a changed driving condition.

The numerical state is invented. These definitions do not give a universal nucleation threshold, growth law, induction time or appropriate cooling profile.

Does the reported supersaturation value use a ratio or a normalized concentration excess?

This blank worksheet is for your own project. It contains no H M machine trial result.

Customer Questions

Primary References

These references support the technical principles discussed in this guide. The worked examples and review questions are educational.

• METTLER TOLEDO's supersaturation explanation
• Reference from hmpharmamachines.com