Tag Archives: LC-MS/MS

dSPE cleanups

The Grass Isn’t Always Greener: Removal of Purple Pigmentation from Cannabis

By Danielle Mackowsky
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dSPE cleanups
strains
Cannabis strains used (clockwise from top left): Agent Orange, Tahoe OG, Blue Skunk, Grand Daddy and Grape Drink

Cannabis-testing laboratories have the challenge of removing a variety of unwanted matrix components from plant material prior to running extracts on their LC-MS/MS or GC-MS. The complexity of the cannabis plant presents additional analytical challenges that do not need to be accounted for in other agricultural products. Up to a third of the overall mass of cannabis seed, half of usable flower and nearly all extracts can be contributed to essential oils such as terpenes, flavonoids and actual cannabinoid content1. The biodiversity of this plant is exhibited in the over 2,000 unique strains that have been identified, each with their own pigmentation, cannabinoid profile and overall suggested medicinal use2. While novel methods have been developed for the removal of chlorophyll, few, if any, sample preparation methods have been devoted to removal of other colored pigments from cannabis.

QuEChERS
Cannabis samples following QuEChERS extraction

Sample Preparation

Cannabis samples from four strains of plant (Purple Drink, Tahoe OG, Grand Daddy and Agent Orange) were hydrated using deionized water. Following the addition of 10 mL acetonitrile, samples were homogenized using a SPEX Geno/Grinder and stainless steel grinding balls. QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) non-buffered extraction salts were then added and samples were shaken. Following centrifugation, an aliquot of the supernatant was transferred to various blends of dispersive SPE (dSPE) salts packed into centrifugation tubes. All dSPE tubes were vortexed prior to being centrifuged. Resulting supernatant was transferred to clear auto sampler vials for visual analysis. Recoveries of 48 pesticides and four mycotoxins were determined for the two dSPE blends that provided the most pigmentation removal.

Seven dSPE blends were evaluated for their ability to remove both chlorophyll and purple pigmentation from cannabis plant material:

  • 150 mg MgSO4, 50 mg PSA, 50 mg C18, 50 mg Chlorofiltr®
  • 150 mg MgSO4, 50 mg C18, 50 mg Chlorofiltr®
  • 150 mg MgSO4, 50 mg PSA
  • 150 mg MgSO4, 25 mg C18
  • 150 mg MgSO4, 50 mg PSA, 50 mg C18
  • 150 mg MgSO4, 25 mg PSA, 7.5 mg GCB
  • 150 mg MgSO4, 50 mg PSA, 50 mg C18, 50 mg GCB

Based on the coloration of the resulting extracts, blends A, F and G were determined to be the most effective in removing both chlorophyll (all cannabis strains) and purple pigments (Purple Drink and Grand Daddy). Previous research regarding the ability of large quantities of GCB to retain planar pesticides allowed for the exclusion of blend G from further analyte quantitation3. The recoveries of the 48 selected pesticides and four mycotoxins for blends A and F were determined.

dSPE cleanups
Grand Daddy following various dSPE cleanups

Summary

A blend of MgSO4, C18, PSA and Chlorofiltr® allowed for the most sample clean up, without loss of pesticides and mycotoxins, for all cannabis samples tested. Average recovery of the 47 pesticides and five mycotoxins using the selected dSPE blend was 75.6% were as the average recovery when including GCB instead of Chlorofiltr® was 67.6%. Regardless of the sample’s original pigmentation, this blend successfully removed both chlorophyll and purple hues from all strains tested. The other six dSPE blends evaluated were unable to provide the sample clean up needed or had previously demonstrated to be detrimental to the recovery of pesticides routinely analyzed in cannabis.


References

(1)           Recommended methods for the identification and analysis of cannabis and cannabis products, United Nations Office of Drugs and Crime (2009)

(2)            W. Ross, Newsweek, (2016)

(3)            Koesukwiwat, Urairat, et al. “High Throughput Analysis of 150 Pesticides in Fruits and Vegetables Using QuEChERS and Low-Pressure Gas Chromatography Time-of-Flight Mass Spectrometry.” Journal of Chromatography A, vol. 1217, no. 43, 2010, pp. 6692–6703., doi:10.1016/j.chroma.2010.05.012.

Ask the Expert: Q&A with Steve Stadlmann on Cannabis lab Accreditation

By Aaron G. Biros
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Steve Stadlmann has an extensive background as an analytical chemist working in laboratories since the early 90’s. He is now a sales specialist at PerkinElmer, an analytical instrument manufacturer that provides instruments for cannabis testing labs, in addition to a host of other industries. With over two decades of experience working in environmental testing labs, food and beverage labs and agricultural testing labs, Stadlmann is extremely familiar with the instruments used in cannabis labs.

Steve Stadlmann, sales specialist at Perkin Elmer

In 2014, he started working in the cannabis space with TriQ, Inc., a technology solutions provider for cannabis growers, where he worked in product development on a line of nutrients. In April of 2016, he started working at Juniper Analytics, a cannabis-testing laboratory in Bend, Oregon. As laboratory director there, he created their quality manual, quality assurance plan, SOP’s and all the technical documentation for ORELAP accreditation. He developed new methodologies for cannabis testing industry for residual solvents, terpene profiles and potency analysis. He worked with PerkinElmer on pesticide methodology for the QSight™ Triple Quadrupole LC/MS/MS system and implemented operational procedures and methods for LC-UV, GCMS and LC-MS/MS, including sample prep for cannabis products.

He left Juniper Analytics about two months ago to work with PerkinElmer as a sales specialist. With extensive experience in helping get Juniper’s lab accredited, he is a wealth of knowledge on all things cannabis laboratory accreditation. PerkinElmer will be hosting a free webinar on September 12th that takes a deep dive into all things cannabis lab accreditation. Ahead of the upcoming webinar, Getting Accreditation in the Cannabis Industry, we sit down with Stadlmann to hear his observations on what instruments he recommends for accreditation, and processes and procedures to support that. Take a look at our conversation below to get a glimpse into what this webinar will discuss.

CannabisIndustryJournal: How can cannabis labs prepare for accreditation with selecting instrumentation?

Steve: Finding the appropriate instrumentation for the regulations is crucial. Ensuring the instrumentation not only has the capabilities of analyzing all the required compounds, but also able to achieve appropriate detection limit requirements. In addition, having an instrument manufacturer as a partner, that is willing and able to assist in method development, implementation and continued changes to the testing requirements at the state level (and potentially national level) is key.

Another consideration is robustness of the equipment. The instrumentation must be capable of high throughput for fast turnaround times of results. Unlike the environmental industry, the cannabis industry has consumer products with expiration dates. Clients demand quick turnaround of results to get product to market as quickly as possible and avoid sitting on inventory for any length of time.

To add to the robustness need, sample matrices in the cannabis industry can be quite challenging in relation to analytical instrumentation. Equipment that is able to handle these matrices with minimal downtime for routine service is becoming a requirement to maintain throughput needs of the industry.

CIJ: What are the most crucial procedures and practices for achieving ISO 17025 accreditation?

Steve: Development and documentation of processes and procedures following Good Laboratory Practices and procedures is essential to a successful accreditation process. Great attention must be paid to the quality objectives of the laboratory as well as associated documentation, including tracking of any errors, deviations, updates, complaints, etc.

Data integrity is a key component to any accrediting body and includes implementation and/or development of appropriate methods with support data proving acceptable results. In addition, documentation of all procedures and processes along with tracking of all steps in the process during routine laboratory work should be a priority. The ability to show a complete, documented trail of all procedures done to any sample is important in ensuring the results can be reproduced and ensuring no deviations occurred, in turn potentially causing questionable results.

Last but not least: training. Laboratory staff should be well versed in any procedures they are involved in to ensure high data quality and integrity. If any laboratory staff does not receive appropriate training in any operating procedures, the data quality becomes suspect.

CIJ: What are some of the biggest obstacles or pitfalls cannabis labs face when trying to get accredited?

Steve: Not fully preparing to meet any agency and testing regulations and requirements will cause delays in the accreditation process and potentially more work for the laboratory. From documentation to daily operations, if any aspect becomes a major finding for an auditor, additional data is usually required to prove the error has been fixed satisfactorily.

Taking the time early on to ensure all documentation, processes and procedures are adhering to any regulatory agency requirements is important for a smooth accreditation process. It is easy to overlook small details when building out the operating procedures that might be essential in the process. Again, going back to data quality, the laboratory must ensure all steps are outlined and documented to ensure high quality (reproducible) data and integrity.

A new employee should be able to come in and read a quality manual and standard operating procedure and produce equivalent data to any laboratory analyst doing the same job. With difficult or challenging operating procedures it becomes even more important that training and documentation are adhered to.


PerkinElmer’s free webinar will dive into these points and others in more detail. To learn more and sign up, click here.

From The Lab

QuEChERS 101

By Danielle Mackowsky
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Sample preparation experts and analytical chemists are quick to suggest QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) to cannabis laboratories that are analyzing both flower and edible material for pesticides, mycotoxins and cannabinoid content. Besides having a quirky name, just what makes QuEChERS a good extraction technique for the complicated matrices of cannabis products? By understanding the chemistry behind the extraction and the methodology’s history, cannabis laboratories can better implement the technology and educate their workforce.

QuEChERS salt blends can be packed into mylar pouches for use with any type of centrifuge tubes
QuEChERS salt blends can be packed into mylar pouches for use with any type of centrifuge tubes

In 2003, a time when only eight states had legalized the use of medical cannabis, a group of four researchers published an article in the Journal of AOAC International that made quite the impact in the residue monitoring industry. Titled Fast and Easy Multiresidue Method Employing Acetonitrile Extraction/Partitioning and “Dispersive Solid-Phase Extraction” for the Determination of Pesticide Residues in Produce, Drs. Michael Anastassiades, Steven Lehotay, Darinka Štajnbaher and Frank Schenck demonstrate how hundreds of pesticides could be extracted from a variety of produce samples through the use of two sequential steps: an initial phase partitioning followed by an additional matrix clean up. In the paper’s conclusion, the term QuEChERS was officially coined. In the fourteen years that have followed, this article has been cited over 2800 times. Subsequent research publications have demonstrated its use in matrices beyond food products such as biological fluids, soil and dietary supplements for a plethora of analytes including phthalates, pharmaceutical compounds and most recently cannabis.

QuEChERS salts can come prepacked into centrifuge tubes
QuEChERS salts can come prepacked into centrifuge tubes

The original QuEChERS extraction method utilized a salt blend of 4 g of magnesium sulfate and 1 g of sodium chloride. A starting sample volume of 10 g and 10 mL of acetonitrile (ACN) were combined with the above-mentioned salt blend in a centrifuge tube. The second step, dispersive solid phase extraction (dSPE) cleanup, included 150 mg of magnesium sulfate and 25 mg of primary secondary amine (PSA). Subsequent extraction techniques, now known as AOAC and European QuEChERS, suggested the use of buffered salts in order to protect any base sensitive analytes that may be critical to one’s analysis. Though the pH of the extraction solvent may differ, all three methods agree that ACN should be used as the starting organic phase. ACN is capable of extracting the broadest range of analytes and is compatible with both LC-MS/MS and GC-MS systems. While ethyl acetate has also been suggested as a starting solvent, it is incompatible with LC-MS/MS and extracts a larger amount of undesirable matrix components in the final aliquot.

All laboratories, including cannabis and food safety settings, are constantly looking for ways to decrease their overhead costs, batch out the most samples possible per day, and keep their employees trained and safe. It is not a stretch to say that QuEChERS revolutionized the analytical industry and made the above goals tangible achievements. In the original publication, Anastassiades et al. established that recoveries of over 85% for pesticides residues were possible at a cost as low as $1 per ten grams of sample. Within forty minutes, up to twelve samples were fully extracted and ready to be analyzed by GC-MS, without the purchase of any specialized equipment. Most importantly, no halogenated solvents were necessary, making this an environmentally conscious concept. Due to the nature of the cannabis industry, laboratories in this field are able to decrease overall solvent usage by a greater amount than what was demonstrated in 2003. The recommended starting sample for cannabis laboratories is only one gram of flower, or a tenth of the starting volume that is commonly utilized in the food safety industry. This reduction in sample volume then leads to a reduction in acetonitrile usage and thus QuEChERS is a very green extraction methodology.

The complexity of the cannabis matrix can cause great extraction difficulties if proper techniques are not used
The complexity of the cannabis matrix can cause great extraction difficulties if proper techniques are not used

As with any analytical method, QuEChERS is not perfect or ideal for every laboratory setting. Challenges remain in the cannabis industry where the polarity of individual pesticides monitored in some states precludes them from being amenable to the QuEChERS approach. For cannabis laboratories looking to improve their pesticide recoveries, decrease their solvent usage and not invest their resources into additional bench top equipment, QuEChERS is an excellent technique to adopt. The commercialization of salt blends specific for cannabis flowers and edibles takes the guesswork out of which products to use. The growth of cannabis technical groups within established analytical organizations has allowed for better communication among scientists when it comes to best practices for this complicated matrix. Overall, it is definitely worth implementing the QuEChERS technique in one’s cannabis laboratory in order to streamline productivity without sacrificing your results.