Accurate Detection of Residual Solvents in Cannabis Concentrates

Author: Chris English

Restek Corporation

Published By: Cannabis Industry Journal

Year of Publication: 2017



Edibles and vape pens are rapidly becoming a sizable portion of the cannabis industry as various methods of consumption popularize beyond just smoking dried flower. These products are produced using cannabis concentrates, which come in the form of oils, waxes, or shatter. Once the cannabinoids and terpenes are removed from the plant material using solvents, the solvent is evaporated leaving behind the product. Extraction solvents are difficult to remove in the low percent range, so the final product is tested to ensure leftover solvents are at safe levels. While carbon dioxide and butane are most commonly used, consumer concern over other more toxic residual solvents has led to regulation of acceptable limits.

Forensic Characterization of Drug Exposure from Skeletal Remains (Featuring Raptor Biphenyl LC columns)

Author: James Watterson

Published By: SelectScience

Year of Publication: 2016



Dr. James Watterson, Associate Professor, Department of Forensic Science at Laurentian University in Ontario, told SelectScience about his forensic toxicology research and the technologies he utilizes in his work. Dr. Watterson’s primary interest is the characterization of drug and metabolite disposition in skeletal remains, and he has employed a variety of chromatography and mass spectrometry-based analyses. The team is now investigating the probative power of quantitative drug-metabolite relationships in bone using LC-MS techniques, which offer greater sensitivity and selectivity for analyses of a number of different metabolites. As Dr. Watterson explains, “Now that we have switched to UPLC-qTOF-MS as our primary analytical approach, the advantages are absolute: substantially reduced sample preparation requirements, vastly improved sensitivity and selectivity, and a much greater of analytes that may be assayed.” The choice of LC column for such analyses is also of critical importance, the correct column chemistry is essential for efficient separation. For example, the team used Raptor Biphenyl columns, with long column geometry and small particle/fused-core stationary phase, to maximize resolution of polar metabolites of phenothiazine drugs, using UPLC-PDA. This approach was critical in the characterization of these metabolites and of the phenothiazine oxidation products, which are produced during sample preparation. Dr. Watterson comments that, “the biphenyl column has been very helpful in resolving those compounds too, as we applied this method to UPLC-qTOF-MS.” Dr. Watterson advises choosing reagents and columns carefully, as background impurities are much more visible using current technologies.

Attend Restek’s Vendor Seminar on GC-MS/MS Performance at RAFA 2015

In addition to exhibiting, Restek will hold a vendor seminar at the 7th International Symposium on Recent Advances in Food Analysis (RAFA). Presented by Restek’s own Julie Kowalski on November 5 at 1:30 p.m., this valuable seminar will explore prolonging GC-MS/MS performance by means of Shoot-and-Dilute injection versus analyte protectants. Prizes will also be given away to select attendees.

RAFA 2015 takes place on November 3–6, 2015 at the Clarion Congress Hotel Prague, Czech Republic. This biennial symposium summarizes the latest strategies and identifies current issues surrounding food quality and safety control analysis and bioanalysis. While at RAFA, be sure to also stop by Booth# 46 for a visit and to discuss our latest innovations in food science.

Visit today to register for the symposium and to sign up for Restek’s vendor seminar.

Prolonging GC-MS/MS Performance: Shoot-and-Dilute Injection versus Analyte Protectants

Thursday, November 5, 1:30 p.m.
Julie Kowalski and Jack Cochran
Restek Corporation

In gas chromatography–mass spectrometry (GC-MS), most problems occur on the front end, at the GC inlet, where compounds can degrade during hot splitless injection, active compounds can be irreversibly adsorbed to inlet liner surfaces, and nonvolatile material from dirty samples can compromise the transfer of less volatile compounds of interest from the inlet to the GC column. These issues are magnified due to the very slow inlet flow during splitless injection, which is typically less than 2 mL/min.

Two strategies to mitigate these issues will be demonstrated in this seminar. One approach is to use split injection, what we call, and “Shoot-and-Dilute.” With newer, more sensitive GC-MS/MS systems, LOD and LOQ requirements are often achievable using split injections at ratios of 10:1 or greater. Increased flow through the inlet during split injection minimizes residence time inside the inlet liner, which decreases compound degradation and adsorption, and maintains acceptable data quality longer. In addition, GC oven start temperature can be higher, thus reducing overall run time as well as the time needed to re-equilibrate the GC oven prior to the next analysis. Another benefit of split injection is improved peak shape for early eluting pesticides when injecting acetonitrile-based QuEChERS extracts.

The second strategy to overcome GC inlet problems is to use “analyte protectants,” which are essentially volatile and chromatograph-able masking agents such as sugars, diols, etc., that are co-injected with each sample and standard to temporarily occupy active sites in the GC inlet liner and column. These analyte protectants have low m/z ions and the mass spectrometer can essentially overlook them in favor of target compounds.

Both strategies were tested with multiclass pesticides and compared against a typical splitless injection method without use of analyte protectants for QuEChERS samples. For Shoot-and-Dilute, viability of split injection based on detectability of a wide range of analytes was determined. Optimized split injection, inlet, and initial GC oven temperatures were determined. Benefits of analyte protectants were evaluated by peak shapes and responses of both well-behaved and problem pesticides. The goal of both Shoot-and-Dilute and analyte protectants approaches is to improve initial and long-term chromatographic performance.

Our MSACL 2015 EU Page is Now Live

Go to our MSACL 2015 EU page for a sneak peek at what we’ll be up to during this year’s show. You can also read abstracts for all of our posters, easily contact the presenters, and access the MSACL website for additional event details.

We’re looking forward to sharing our latest innovations for clinical mass spectrometry—and answering any questions you may have about how Restek® products and services can help you. See you there!

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