Carbowax 20M & HP-20M

Carbowax 20M & HP-20M GC Columns

Agilent Carbowax 20M and HP-20M GC columns are classic high-polarity polyethylene glycol (PEG) phases widely used for the separation of alcohols, esters, glycols, organic acids, and other oxygenated compounds. These traditional PEG columns provide strong hydrogen-bonding interactions and well-established selectivity patterns, making them suitable for methods that explicitly require Carbowax-type stationary phases or legacy workflows that depend on historical retention data.

Carbowax 20M and HP-20M columns deliver sharp peak shapes and dependable chromatographic behavior for polar analytes, supporting applications in food and flavor chemistry, industrial solvent analysis, environmental sample testing, and specialty chemical workflows. Their high polarity enables clear resolution of low-molecular-weight volatiles, as well as differentiation of similar oxygenated species that are difficult to separate on nonpolar or mid-polar phases.

While these columns do not feature bonded or crosslinked chemistries, their traditional PEG design provides the selectivity required for methods where Carbowax-equivalent phases remain specified. Both Carbowax 20M and HP-20M maintain consistent performance across moderate temperatures and are available in a variety of column dimensions to support different analytical requirements, including legacy EPA, ASTM, and industry-standard protocols.

With long-standing use in laboratories worldwide, these columns continue to serve as dependable solutions for analysts who require authentic Carbowax-type PEG selectivity, traditional retention patterns, and reproducible performance in established GC methods.

Key Definitions â–¸
Carbowax 20M Phase
A traditional high-polarity polyethylene glycol (PEG) stationary phase widely used in legacy GC methods. Carbowax 20M provides strong hydrogen-bonding interactions, making it suitable for alcohols, acids, esters, glycols, and other oxygenated volatiles.
HP-20M
Agilent’s high-purity version of the Carbowax 20M PEG phase. HP-20M offers the same classic selectivity but is formulated with improved consistency and lower baseline noise compared to older Carbowax-style implementations.
High-Polarity PEG Columns
GC columns that use polyethylene glycol as the stationary phase, designed to separate strongly polar analytes. These columns provide excellent selectivity for alcohols, organic acids, flavor compounds, and environmental volatiles.
Legacy Selectivity
A term used for stationary phases like Carbowax 20M & HP-20M whose historical retention patterns are well established and still required for older EPA, ASTM, and industry-specific methods. These phases ensure continuity with validated or long-running workflows.
Non-Bonded PEG Phase
Unlike bonded or crosslinked WAX columns, Carbowax 20M & HP-20M phases are not chemically attached to the capillary surface. This preserves their classic selectivity but typically results in lower thermal limits and reduced solvent tolerance compared to bonded PEG columns.
Frequently Asked Questions â–¸
What types of compounds are best analyzed with Carbowax 20M or HP-20M columns?
These columns excel at separating polar, oxygenated analytes including alcohols, esters, aldehydes, ketones, organic acids, glycols, and flavor or fragrance compounds. Their high polarity provides strong hydrogen-bonding interactions ideal for resolving challenging oxygenated species.
How are Carbowax 20M and HP-20M different from bonded PEG columns like DB-WAX or HP-INNOWax?
Carbowax 20M and HP-20M are traditional non-bonded PEG phases. While they provide classic WAX selectivity, they have lower thermal limits and cannot be solvent rinsed like bonded PEG columns. HP-INNOWax and DB-WAX offer greater stability, lower bleed, and improved durability—but Carbowax-type columns remain essential for legacy or method-specific selectivity requirements.
Can Carbowax 20M or HP-20M be used in GC/MS applications?
Yes, they can be used for GC/MS work; however, their non-bonded PEG chemistry often results in higher bleed than bonded PEG phases. For low-level GC/MS quantitation or high sensitivity, bonded WAX columns may be preferred, but Carbowax 20M and HP-20M remain valid choices for methods that specify these traditional phases.
Are Carbowax 20M and HP-20M suitable for EPA or ASTM legacy methods?
Absolutely. Many older EPA, ASTM, and industry-specific methods were developed using Carbowax-type PEG columns. Carbowax 20M and HP-20M ensure compatibility with these legacy methods and preserve established retention-time patterns critical for regulatory compliance.
What is the benefit of HP-20M versus standard Carbowax 20M?
HP-20M is Agilent’s higher-purity version of Carbowax 20M, offering improved batch consistency, cleaner baselines, and more stable retention behavior. It maintains identical selectivity but provides enhanced reproducibility for more demanding analytical applications.