The Inert Flow Path Story: Continuous Improvements in Result Fidelity for Challenging Analytes

Oral Presentation

Prepared by K. Lynam1, G. Lee2
1 - Agilent Cross Lab Group, 2850 Centerville Road, Wilmington, DE, 19808, United States
2 - Agilent Technologies, Inc., 91 Blue Ravine Road, Folsom, CA, 95630, United States

Contact Information:; 302-636-8162


The story begins with columns, moves to liner improvements, encompasses innovative designs in new ferrules and fittings, expands to liquid phase connections, and now includes the first inert polyethylene glycol column available. The stories path continues thru innovations in measurement science.

Analysts working with GC and GC/MS systems often need to retighten fittings as the materials in some ferrules shrink with repeated heat cycling. An innovative self-tightening column nut eliminates the need to retighten these fittings conquering a legacy problem that many labs have learned to work around. These new fittings coupled with a suite of deactivated connectors for gas phase applications make forming and maintaining gas tight connections easy and reliable.

Analysts working with HPLC and UHPLC are often challenged by problems such as peak tailing, peak broadening, split peaks, carryover, etc. One common cause for these problems that is often overlooked, and time consuming for troubleshooting, is bad tubing connections. Dead volume or micro-leakage in tubing connections can strongly affect the performance and reproducibility of HPLC and UHPLC analysis, especially with ultra-high pressures and small column dimensions.

Polyethylene glycol (PEG) or wax based GC columns are staples in laboratories analyzing alcohols, acids, essential oils, fragrances, flavors, spirits, solvents, and fatty acids. Problematic analytes on PEG phases include diols, glycols, and ethyl maltol to name just a few. The chromatographic behavior of these compounds and other challenging analytes illustrate just how peak shape and run to run repeatability improve the fidelity of results when an inert wax column is used versus traditional wax columns. The difference between inert and typical wax based columns is striking for many of these challenging analytes, showing convincingly that all wax based columns are not equal.

Continuous improvements in column manufacturing coupled with rigorous testing procedures and a relentless commitment to improve the inertness performance of our products have all been key facets in the successful development of our new inert wax columns.