A Study of Filter Types Used in Sample Preparation of Cannabis/Hemp with HPLC Analysis

Introduction

Filtration is a critical step in preparing cannabis and hemp samples for HPLC potency analysis. Fine particles must be removed to make the sample suitable for HPLC injection, following extraction into a suitable solvent. Syringe filters, while effective for particulate removal, can sometimes be problematic in terms of analyte adsorption, resulting in some loss of target recovery.

We conducted a study to determine the recovery of phytocannabinoids (in terms of concentration) using several syringe filters. Seven types of syringe filters were tested with methanol used as the solvent medium, as per the manufacturer’s recommendation. Our goal was to determine the recovery (without pre-wetting) of phytocannabinoids using seven different types of filters; polyvinylidene difluoride (PVDF-hydrophobic), modified polyvinylidene difluoride (PVDF-hydrophilic), polypropylene (PP), polytetrafluoroethylene (PTFE-hydrophobic), nylon, cellulose acetate (CA) and polyether sulfone (PES).