Impact of GC Parameters on the Separation Part 4: Choice of Film Thickness

Author(s): Jaap de Zeeuw
Restek Corporation

Published By: Separation Science

Year of Publication: 2014


Abstract: In parts 1, 2, and 3 of this series, we focused on the selection of stationary phase, column length, and internal diameter. The stationary phase is also deposited as a film or a layer, which is the fourth parameter, and we need to understand its impact. The thickness of the layer determines the amount of the stationary phase that is present in the capillary. Retention is directly related to the amount of the stationary phase; thicker films equal more retention. When do we choose thin or thick films and how do they impact the chromatography? Changing film thickness will impact several parameters: retention, loadability, bleed, efficiency, and even inertness.

A Rapid and Sensitive LC-MS/MS Method for the Analysis of Three Forms of Thyroid Hormones Using Raptor™ Biphenyl LC Columns

Author(s): Shun-Hsin Liang, Paul Connolly, and Ty Kahler
Restek Corporation

Published By: Restek Corporation

Year of Publication: 2014


Abstract: The Raptor™ Biphenyl column is excellent for rapid and sensitive analysis of thyroid hormones. With the method described here, concentrations of thyroid hormones as low as 2 pg/mL (T3) or 5 pg/mL (T4 and rT3) can be determined with less than 3.5 minutes of total analysis time. The analytical method is thus applicable to the clinical analysis of free thyroid hormone at low pg/mL levels.

The Industry’s Favorite Reference Standards Packaging Just Got Better—Restek Begins Transition to GHS Labeling

ampule_box_2_ph_arm_2Effective immediately, Restek will be transitioning away from NFPA* to universally recognized GHS labeling for our reference standards.

GHS, or the Globally Harmonized System of Classification and Labeling of Chemicals, is a set of provisions for hazard classification and communication developed by the United Nations. Its goal is to universally label products that can be opened, thus exposing users to the materials contained within, in a way that clearly identifies any potential safety concerns regardless of the user’s language, country, or background. Efforts to implement GHS labeling have begun around the globe; for the United States in particular, OSHA will require that products shipped after June 1, 2015, carry universally recognized GHS labeling to ensure safety regulation compliance.

In order to improve the safety communication included with Restek® reference standards and ensure that we can provide uninterrupted service to our customers, Restek has already started phasing out our use of NFPA labeling. During the transition, Restek customers may receive a mix of GHS- and NFPA-labeled reference standards, but our entire reference standard inventory will be converted to GHS labeling well in advance of the June 1, 2015 deadline. In the near future, we will also begin transitioning our wool, bulk packings for GC and LC columns, and other products to GHS labeling.

Restek has extensively studied the GHS system and OSHA’s requirements for using it to help our customers not only convert their own inventories properly, but also do so ahead of schedule. This change will not affect product composition or quality in any way; it is merely a change in labeling practices. Our goal is to make the transition to GHS labeling compliance as seamless as possible. Our new convenient GHS labels are bar coded with both catalog and lot number, and they are also removable for easy transfer of standard information into lab notebooks.

The conversion to GHS may seem like a challenge to many labs, but relying on Restek’s safety compliance experts and using our reference standards is one way to make the transition easier.

If you have any questions about GHS labeling for Restek® reference standards, contact Jason Fisher at 1‐814‐353‐1300, ext. 2409, or

* Hazard labeling that follows NFPA (National Fire Protection Association) 704 standards is best known for the use of 4 colored diamonds, each most often containing a numeric code.

Analysis of Gases and Low Boiling Point Samples Using Highly Retentive Stationary Phases (Chapter 18 in Practical Gas Chromatography)

Author(s): Jaap de Zeeuw
Restek Corporation

Published By: Springer

Year of Publication: 2014


View flyer: productFlyer_978-3-642-54639-6

Chapter alone:

Full book:

Abstract: In this chapter of the newly published book, Practical Gas Chromatography (eds. Katja Dettmer-Wilde and Werner Engewald), author Jaap de Zeeuw discusses the chromatographic behavior of several volatile compound classes when analyzed using the most current GC stationary phase and column technologies. Most of the applications shown are performed using gas-solid chromatography on capillary columns, as those materials provide the most retention for volatiles. The adsorption separations shown are all qualitative examples, but give a clear indication what is possible with modern GC technology.