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.
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:
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.
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.
(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.
With the state led legalization of both adult recreational and medical cannabis, there is a need for comprehensive and reliable analytical testing to ensure consumer safety and drug potency. Cannabis-testing laboratories receive high volumes of test requests from cannabis cultivators for testing quantitative and qualitative aspects of the plant. The testing market is growing as more states bring in stricter enforcement policies on testing. As the number of testing labs grow, it is anticipated that the laboratories that are now servicing other markets, including high throughput contract labs, will cross into cannabis testing as regulations free up. As the volume of tests each lab performs increases, the need for laboratories to make effective use of time and resource management, such as ensuring accurate and quick results, reports, regulatory compliance, quality assurance and many other aspects of data management becomes vital in staying competitive.
Cannabis Testing Workflows
To be commercially competitive, testing labs offer a comprehensive range of testing services. These services are available for both the medical and recreational cannabis markets, including:
Detection and quantification of both acid and neutral forms of cannabinoids
Screening for pesticide levels
Monitoring water activity to indicate the possibility of microbiological contamination
Moisture content measurements
Residual solvents and heavy metal testing
Fungi, molds, mycotoxin testing and many more
Although the testing workflows differ for each test, here is a basic overview of the operations carried out in a cannabis-testing lab:
Cannabis samples are received.
The samples are processed using techniques such as grinding and homogenization. This may be followed by extraction, filtration and evaporation.
A few samples will be isolated and concentrated by dissolving in solvents, while others may be derivatized using HPLC or GC reagents
The processed samples are then subjected to chromatographic separation using techniques such as HPLC, UHPLC, GC and GC-MS.
The separated components are then analyzed and identified for qualitative and quantitative analysis based on specialized standards and certified reference materials.
The quantified analytical data will be exported from the instruments and compiled with the corresponding sample data.
The test results are organized and reviewed by the lab personnel.
The finalized test results are reported in a compliant format and released to the client.
In order to ensure that cannabis testing laboratories function reliably, they are obliged to follow and execute certain organizational and regulatory protocols throughout the testing process. These involve critical factors that determine the accuracy of testing services of a laboratory.
Factors Critical to a Cannabis Testing Laboratory
Accreditations & Regulatory Compliance: Cannabis testing laboratories are subject to regulatory compliance requirements, accreditation standards, laboratory practices and policies at the state level. A standard that most cannabis testing labs comply to is ISO 17025, which sets the requirements of quality standards in testing laboratories. Accreditation to this standard represents the determination of competence by an independent third party referred to as the “Accreditation Body”. Accreditation ensures that laboratories are adhering to their methods. These testing facilities have mandatory participation in proficiency tests regularly in order to maintain accreditation.
Quality Assurance, Standards & Proficiency Testing: Quality assurance is in part achieved by implementing standard test methods that have been thoroughly validated. When standard methods are not available, the laboratory must validate their own methods. In addition to using valid and appropriate methods, accredited laboratories are also required to participate in appropriate and commercially available Proficiency Test Program or Inter-Laboratory Comparison Study. Both PT and ILC Programs provide laboratories with some measure of their analytic performance and compare that performance with other participating laboratories.
Real-time Collaboration: Testing facilities generate metadata such as data derived from cannabis samples and infused products. The testing status and test results are best served for compliance and accessibility when integrated and stored on a centralized platform. This helps in timely data sharing and facilitates informed decision making, effective cooperation and relationships between cannabis testing facilities and growers. This platform is imperative for laboratories that have grown to high volume throughput where opportunities for errors exist. By matching test results to samples, this platform ensures consistent sample tracking and traceability. Finally, the platform is designed to provide immediate, real-time reporting to individual state or other regulatory bodies.
Personnel Management: Skilled scientific staff in cannabis-testing laboratories are required to oversee testing activities. Staff should have experience in analytical chromatography instruments such as HPLC and GC-MS. Since samples are often used for multi-analytes such as terpenes, cannabinoids, pesticides etc., the process often involves transferring samples and tests from one person to another within the testing facility. A chain of custody (CoC) is required to ensure traceability and ‘ownership’ for each person involved in the workflow.
LIMS for Laboratory Automation
Gathering, organizing and controlling laboratory-testing data can be time-consuming, labor-intensive and challenging for cannabis testing laboratories. Using spreadsheets and paper methods for this purpose is error-prone, makes data retrieval difficult and does not allow laboratories to easily adhere to regulatory guidelines. Manual systems are cumbersome, costly and lack efficiency. One way to meet this challenge is to switch to automated solutions that eliminate many of the mundane tasks that utilize valuable human resources.. Laboratory automation transforms the data management processes and as a result, improves the quality of services and provides faster turnaround time with significant cost savings. Automating the data management protocol will improve the quality of accountability, improve technical efficiency, and improve fiscal resources.
A Laboratory Information Management System (LIMS) is a software tool for testing labs that aids efficient data management. A LIMS organizes, manages and communicates all laboratory test data and related information, such as sample and associated metadata, tests, Standard Operating Procedures (SOPs), test reports, and invoices. It also enables fully automated data exchange between instruments such as HPLCs, GC-FIDs, etc. to one consolidated location, thereby reducing transcription errors.
How LIMS Helps Cannabis Testing Labs
LIMS are much more capable than spreadsheets and paper-based tools for streamlining the analytical and operational lab activities and enhances the productivity and quality by eliminating manual data entry. Cloud-enabled LIMS systems such as CloudLIMS are often low in the total cost of acquisition, do not require IT staff and are scalable to help meet the ever changing business and regulatory compliance needs. Some of the key benefits of LIMS for automating a cannabis-testing laboratory are illustrated below [Table 1]:
Barcode label designing and printing
Enables proper labelling of samples and inventory
Follows GLP guidelines
Instant data capture by scanning barcodes
Facilitates quick client registration and sample access
3600 data traceability
Saves time and resources for locating samples and other records
Inventory and order management
Supports proactive planning/budgeting and real time accuracy
Promotes overall laboratory organization by assigning custodians for samples and tests
Maintains the Chain-of-custody (CoC)
Accommodates pre-loaded test protocols to quickly assign tests for incoming samples
Accounting for sample and inventory quantity
Automatically deducts sample and inventory quantities when consumed in tests
Package & shipment management
Manages incoming samples and samples that have been subcontracted to other laboratories
Electronic data import
Electronically imports test results and metadata from integrated instruments
Eliminates manual typographical errors
Generates accurate, customizable, meaningful and test reports for clients
Allows user to include signatures and additional sections for professional use
21 CFR Part 11 compliant
Authenticates laboratory activities with electronic signatures
ISO 17025 accreditation
Provides traceable documentary evidence required to achieve ISO 17025 accreditation
Audit trail capabilities
Adheres to regulatory standards by recording comprehensive audit logs for laboratory activities along with the date and time stamp
Centralized data management
Stores all the data in a single, secure database facilitating quick data retrieval
Promotes better data management and resource allocation
Enables modification of screens using graphical configuration tools to mirror testing workflows
State compliance systems
Integrates with state-required compliance reporting systems and communicates using API
Adheres to regulatory compliance
Creates Certificates of Analysis (CoA) to prove regulatory compliance for each batch as well as batch-by-batch variance analysis and other reports as needed.
Data security & confidentiality
Masks sensitive data from unauthorized user access
Cloud-based LIMS encrypts data at rest and in-transit while transmission between the client and the server
Cloud-based LIMS provides real-time access to laboratory data from anytime anywhere
Cloud-based LIMS enhances real-time communication within a laboratory, between a laboratory and its clients, and across a global organization with multiple sites
Table 1. Key functionality and benefits of LIMS for cannabis testing laboratories
Upon mapping the present day challenges faced by cannabis testing laboratories, adopting laboratory automation solutions becomes imperative. Cloud-based LIMS becomes a valuable tool for laboratory data management in cannabis testing laboratories. In addition to reducing manual workloads, and efficient resource management, it helps labs focus on productive lab operations while achieving compliance and regulatory goals with ease.
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.
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.
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.
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.
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.
A CRM is an exclusive reference material that meets strict criteria defined by ISO Guide 34 and ISO/IEC 17025. ISO is the International Organization for Standardization and IEC is the International Electrotechnical Commission. These organizations work together to set globally recognized standards. In order for a reference material to be labeled as a CRM it must 1) be made with raw or starting materials which are characterized using qualified methods and instruments, 2) be produced in an ISO-accredited lab under documented procedures, and 3) fall under the manufacturer’s scopes of accreditation. Verifying a CRM supplier has these credentials is easily done by viewing their certificates which should include their scopes of accreditation.
There are many steps required to produce a CRM that meets the above three criteria. The first step requires a review of the customer’s, or end-user’s requirements to carefully define what is to be tested, at what levels and which analytical workflow will be used. Such information enables the producer to identify the proper compounds and solvents required to properly formulate the requested CRM.
The next step requires sourcing and acquiring the raw, or starting materials, then verifying their compatibility and stability using stability and shipping studies in accordance with ISO requirements. Next the chemical identify and purity of the raw materials must be characterized using one or more analytical techniques such as: GC-FID, HPLC, GC-ECD, GC-MS, LC-MS, refractive index and melting point. In some cases, the percent purity is changed by the producer when their testing verifies it’s different from the supplier label. All steps are of course documented.
The producer’s analytical balances must be verified using NIST traceable weights and calibrated annually by an accredited third party provider to guarantee accurate measurement. CRMs must be prepared using Class A volumetric glassware, and all ampules and vials used in preparation and final packaging must be chemically treated to prevent compound degradation during storage. Next, CRMs are packaged in an appropriate container, labeled then properly stored to maintain the quality and stability until it’s ready to be shipped. All labels must include critical storage, safety and shelf life information to meet federal requirements. The label information must be properly linked to documentation commonly referred to as a certificate of analysis (COA) which describes all of the above steps and verifies the traceability and uncertainty of all measurements for each compound contained in the CRM.
My company, RESTEK, offers a variety of documentation choices to accompany each CRM. Depending on the intended use and data quality objectives specified by the end-user, which were defined way back at the first step, three options are typically offered: They include gravimetric only, qualitative which includes gravimetric, and fully quantitative which includes all three levels of documentation. The graphic to the right summarizes the three options and what they include.
It’s important to understand which level you’re purchasing especially when ordering a custom CRM from a supplier. Most stock CRMs include all three levels of documentation, but it’s important to be sure.
Understanding what must be done to produce and deliver a CRM sets it apart from other reference material types, however it’s important to understand there are some instances where CRMs are either not available, nor required and in those situations other types of reference materials are perfectly acceptable.
If you have any questions or would like more details about reference materials please contact me, Joe Konschnik at (800) 356-1688 ext. 2002 by phone, or email me at firstname.lastname@example.org.
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