Rapid Analysis of C3 Epimers of 25-Hydroxyvitamin D in Serum by LC-MS/MS

Author: Shun-Hsin Liang, Frances Carroll

Restek Corporation

Published By: Restek Corporation

Year of Publication: 2017

Link: http://www.restek.com/Technical-Resources/Technical-Library/Clinical-Forensic-Toxicology/cft_CFAN2612-UNV

Abstract:

The C3 epimers of 25-hydroxyvitamin D have lower bioactivity than the primary metabolites and, unless they are chromatographically separated, can cause clinical vitamin D levels to be overestimated. Raptor FluoroPhenyl columns provide baseline resolution of all key compounds, and the method established here allows accurate quantification in a fast, 5-minute analysis time (7-minute total cycle time). This method is recommended for labs interested in reporting C3 epimer concentrations separately in order to obtain more accurate results for the clinical diagnosis of vitamin D status.

Effects of Column Inner Diameter and Packed Bed Heterogeneities on Chromatographic Performance

Author: Edward G. Franklin, Ty W. Kahler

Restek Corporation

Published By: LC-GC

Year of Publication: 2016

Link: http://www.chromatographyonline.com/effects-column-inner-diameter-and-packed-bed-heterogeneities-chromatographic-performance?topic=100,114&CID=lcgcesepsolutions.1626861.LCGC*%2520-%2520E-Separation%2520Solutions%2520%7c%2520Semi-monthly&eid=243284782&bid=1626861performance?topic=100,114&CID=lcgcesepsolutions.1626861.LCGC*%2520-%2520E-Separation%2520Solutions%2520%7c%2520Semi-monthly&eid=243284782&bid=1626861

Abstract:

In recent years industry has been moving to columns with smaller and smaller inner diameters—moving from 4.6 and 3.0 mm i.d. columns to 2.1 mm, 1.0 mm, and even smaller. While small inner diameter columns have some clear advantages, they also bring challenges.  Reduction of extra column volumes must be given greater consideration by both customers and manufacturers. This installment of “Column Watch” focuses on the sources of band broadening within high performance liquid chromatography (HPLC) columns with an emphasis on eddy dispersion. The physical mechanisms of dispersion are discussed and a review of the current literature as it pertains to small inner diameter columns is presented.

Potency Analysis of Cannabis and Derivative Products: Part 2

Author: Rebecca Stevens

Restek Corporation

Published By: Cannabis Industry Journal

Year of Publication: 2016

Link: https://www.cannabisindustryjournal.com/column/potency-analysis-of-cannabis-and-derivative-products-part-2/

Abstract:

For potency analysis via HPLC, grinding/homogenization and alcohol extraction is a common sample prep technique for dried flower and extracts.

As mentioned in Part 1, the physiological effects of cannabis are mediated by a group of structurally related organic compounds known as cannabinoids. The cannabinoids are biosynthetically produced by a growing cannabis plant and Figure 1 details the biosynthetic pathways leading to some of the most important cannabinoids in plant material.

The analytical measurement of cannabinoids is important to ensure the safety and quality of cannabis as well as its extracts and edible formulations. Total cannabinoid levels can vary significantly between different cultivars and batches, from about 5% up to 20% or more by dry weight. Information on cannabinoid profiles can be used to tailor cultivars for specific effects and allows end users to select an appropriate dose.

Appropriate Instrumentation for the Chemical Analysis of Cannabis and Derivative Products: Part 1

Author: Rebecca Stevens

Restek Corporation

Published By: Cannabis Industry Journal

Year of Publication: 2016

Link: https://www.cannabisindustryjournal.com/column/appropriate-instrumentation-for-the-chemical-analysis-of-cannabis-and-derivative-products-part-1/

Abstract:

The introduction of a series of articles focusing on the applications of instruments for different types of chemical analyses.

Election Day 2016 resulted in historic gains for state level cannabis prohibition reform. Voters in California, Maine, Massachusetts and Nevada chose to legalize adult use of Cannabis sp. and its extracts while even traditionally conservative states like Arkansas, Florida, Montana and North Dakota enacted policy allowing for medical use. More than half of the United States now allows for some form of legal cannabis use, highlighting the rapidly growing need for high quality analytical testing.

For the uninitiated, analytical instrumentation can be a confusing mix of abbreviations and hyphenation that provides little obvious information about an instrument’s capability, advantages and disadvantages. In this series of articles, my colleagues and I at Restek will break down and explain in practical terms what instruments are appropriate for a particular analysis and what to consider when choosing an instrumental technique.

Highly Reproducible Detailed cis/trans FAMEs Analysis Ensured by New Optimized Rt-2560 Column Manufacturing and Application-Specific QC Test

Author(s): Kristi Sellers and Rebecca Stevens

Restek Corporation

Published By: Restek Corporation

Year of Publication: 2016

Link: http://www.restek.com/Technical-Resources/Technical-Library/Foods-Flavors-Fragrances/fff_FFAR2589-UNV

Abstract:
Even minor variations in manufacturing processes can potentially have detrimental effects on column-to-column reproducibility. As shown here, Rt-2560 GC columns produced using a newly updated and optimized manufacturing process exhibit high reproducibility and provide consistent performance for detailed cis/trans FAMEs analysis.

Rt-2560 Columns Ensure Accurate, Reliable AOAC 996.06 and AOCS Ce 1j-07 FAMEs Analysis

Author(s): Rebecca Stevens and Kristi Sellers

Restek Corporation

Published By: Restek Corporation

Year of Publication: 2016

Link: http://www.restek.com/Technical-Resources/Technical-Library/Foods-Flavors-Fragrances/fff_FFAR2588-UNV

Abstract:
Restek has optimized the manufacturing process and implemented a new, application-specific QC testing procedure for all new Rt-2560 columns (cat.# 13198). Here we demonstrate that, Rt-2560 columns produced using the optimized process exhibit excellent performance for both AOAC 996.06 and AOCS Ce 1j-07 FAMEs analysis and meet all method requirements.

Building the Foundation of Medical Cannabis Testing – Understanding the Use of Standards and Reference Materials – Part 2

Author: Joe Konschnik

Restek Corporation

Published By: Cannabis Industry Journal

Year of Publication: 2016

Link: https://www.cannabisindustryjournal.com/column/building-the-foundation-of-medical-cannabis-testing-understanding-the-use-of-standards-and-reference-materials-part-2/

Abstract:

In the last article I referred to the analogy of the analytical reference material being a keystone of the laboratory foundation, the stone upon which all data relies. I then described the types of reference materials and their use in analytical testing in general terms. This article will describe the steps required to properly manufacture and deliver a certified reference material (CRM) along with the necessary documentation.

Building the Foundation of Medical Cannabis Testing – Understanding the Use of Standards and Reference Materials – Part 1

Author: Joe Konschnik

Restek Corporation

Published By: Cannabis Industry Journal

Year of Publication: 2016

Link: https://www.cannabisindustryjournal.com/column/building-the-foundation-of-medical-cannabis-testing-understanding-the-use-of-standards-and-reference-materials-part-1/

Abstract:

In previous articles, you may recall that Amanda Rigdon, one our contributing authors, stated that instrument calibration is the foundation of all data quality. In this article, I would like to expand on that salient point. A properly calibrated instrument will, in fact, produce reliable data. It is the foundation we build our data upon. All foundations are comprised of building blocks, and our laboratory is no exception. If we take this analogy further, the keystone to the laboratory foundation, the stone that all data relies upon, is the analytical reference material. Proper calibration means that it is based on a true, accurate value. That is what the reference material provides. In this article, I would like to expand on the use and types of reference materials in analytical testing.

Method Translation in Gas Chromatography: Get the Same Chromatogram when Changing Flow, Pressure Drop, Column Dimensions or Carrier Gas

Author: Jaap de Zeeuw, Chris English, Jack Cochran, Chris Nelson

Published By: Separation Science

Year of Publication: 2016

Link: http://www.sepscience.com/docs/Articles/Oct2016/Jaap_Method_Translation_in_GC.pdf

Abstract:

In gas chromatography there is often a need to optimize separations for the sake of resolution, analysis time or cost of analysis. This can be realized by using different column dimensions, different linear gas velocity, using a different detector or using a different carrier gas. If one wants to get the same peak elution order and the same chromatogram, one must make sure that the elution temperatures of the components are kept the same. This is only possible by adjusting the oven temperature programme. Read more to find out how you can achieve this desired result.

DiatoSorb-W Diatomaceous Earth: Great Chromatography Millions of Years in the Making

Published By: Restek Corporation

Year of Publication: 2016

Link: http://www.restek.com/Technical-Resources/Technical-Library/Petroleum-Petrochemical/General_GNAR2326-UNV

Abstract:

This technical article introduces DiatoSorb-W, a new diatomaceous earth solid support for packed GC columns. Virtually unlimited in supply—but only available from Restek—new DiatoSorb-W diatomaceous earth offers a reliable alternative for packed column users. After years of dealing with supply shortages and inconsistent product quality, analysts who depend on diatomaceous earth columns now have a reliable new source. Restek now uses DiatoSorb-W as the exclusive replacement to the diatomaceous earth that was previously used in our standard and Silcoport W GC packed columns lines. All DiatoSorb-W material undergoes rigorous quality testing to ensure high purity and dependable performance. DiatoSorb-W material is available in acid-washed (WAW), non-acid washed (WNAW), and high-performance (WHP) varieties.