# Impact of Lactose Phosphate Impurities on Lactose Crystallization: Deionization as Effective Pretreatment

## TL;DR

This study shows how lactose phosphate impurities affect lactose crystal formation and how deionization can help produce better crystals.

## Contribution

A new pH-based method is introduced to measure lactose phosphate and its effect on crystallization, with deionization as an effective pretreatment.

## Key findings

- Lactose phosphate impurities influence the crystallization kinetics of α-lactose monohydrate.
- Deionization using ion-exchange beads removes lactose phosphate and improves crystal aspect ratio.
- A pH measurement approach effectively quantifies lactose phosphate incorporation during crystallization.

## Abstract

Commercial α-lactose monohydrate powders contain
trace amounts
of lactose phosphate impurities. In this work, the influence of lactose
phosphate on the crystallization of α-lactose monohydrate from
aqueous solutions is experimentally investigated by varying both the
seed mass and the initial supersaturation. A novel approach based
on pH measurements is proposed to quantify the concentration of lactose
phosphate in solution and its incorporation into lactose crystals
during the crystallization process. Deionization of lactose solution
prior to crystallization using ion-exchange beads effectively removes
the lactose phosphate and enables a clear assessment of the impact
of these ionic impurities on the crystallization kinetics and the
aspect ratio of the resulting lactose crystals.