HSM2 Column Classification System

WHAT IS THE HSM2 CLASSIFICATION SYSTEM?

 The Hydrophobic Subtraction Model (HSM), developed by Lloyd Snyder, John Dolan, and coworkers in 2002, is arguably the most successful classification system for reversed phase columns. In HSM, columns are characterised by numerical parameters (H, A, B, C, S) that describe the retention mechanisms of the stationary phase: hydrophobic, hydrogen bonding, ion exchange, and steric selectivity.

In 2020, we redefined HSM to better understand modern stationary phases (PFP, polar embedded, mixed mode…) and their interactions with analytes of different chemistries. The result of that effort was HSM2, an enhanced model with twice the accuracy of the original HSM and a database of more than 550 commercial columns.

HSM2 underpins our free column consultancy service. Tell us about your separation needs, and we will produce a visual report recommending equivalent, alternative, or orthogonal columns to tackle your chromatography challenge, complete with personalised notes for easy method transfer and optimisation.