Recently, we have been witnessing new and emerging growth in the Cannabis products’ industry and quality control testing laboratories as a result of new regulatory requirements. In addition, patients and clients expectations for safe and effective cannabis products increased the awareness for quality and standardization within the cannabis industry.

From an analytical lab perspective, Cannabis is definitely a challenge. It contains sticky and lipophilic materials which are hard to work with and contains lots of chlorophyll and waxes.

Cannabis plants are the starting material for a variety of recreational as well as medical cannabis products such as oils, powders, beverages, edibles, tablets, capsules, cream, pastes and many more. As a result, preparation of Cannabis products samples and analysis are often confused with the establishment of a qualified process. For example background “noise” elimination, laboratory equipment proper function and protection, etc. Usually, Cannabis products contain excipients except for known Cannabis botanic materials such as Cannabinoids. Although Cannabis products contain inactive materials which are defined as constant and not changeable within the matrix of oils, powders, cookies, tablets etc, it affects the Cannabis active materials analysis and testing results consistency and laboratory personnel should be experienced working and dealing with these kinds of changes.

Cannabis floral tops usually contain 20-30% Cannabinoids, 2-3% Terpenes (light and heavy) and are 60-80% lipids, waxes, carbohydrates, flavonoids, alkaloids and other materials by dry weight. In the process of specific Cannabis materials concentrate preparations and isolation, such as CBD and THC, the verity of molecules narrow down.

Due to the fact that Cannabis contains many different compounds and Cannabis production processes involve agricultural as well as industrial sub-processes, there is a greater risk for contamination, faults, miss-handling, mix-ups and deviations that should be minimized by standardization and control. Procedures, SOPs, detailed working instructions, calibrations, in-process controls, and validations are a must in order to ensure the final product meets the release specifications and the product is safe and effective for medical usage.

Cannabis physical, analytical and microbial testing

The standard physical, analytical and microbial tests being performed for Cannabis dry flowers and final product are:

Moisture (water) content

In order to ensure proper drying, curing and storage conditions, to minimize the risk for mold formation, to control microbiological levels and to support product shelf life, the water content in the Cannabis flowers should be controlled and tested during and after the drying and curing process. In addition, several Cannabis products manufacturing processes require a specific level of water content in the starting material. Water content is measured and tested using KF (Karl Fischer) apparatus or LOD (Loss On Drying). For analysis based on weight loss, such as LOD, it is influenced by VOC’s (Volatile organic Carbons) as it can be evaporated from the plant material (sample is heated to 105oC) as part of the analysis and may cause miscalculations. All of this depends on the material composition of the Cannabis flower, light trepans for example.

The Karl Fisher test utilizes titration, to sum up only the water content in the sample. The sample preparation is the same as for LOD, but other VOC’s are not counted in the analysis. The solvents being used in Karl-Fischer analysis must be carefully chosen, hence, Cannabis contains Ketones and Aldehydes which are known to affect the standard solvents reaction.

Cannabinoids and Terpenoids analysis

This is usually performed using LC or GC coupled with UV or MS detectors or by IR spectrometry. The concentration of Cannabinoids and Terpenoids in the starting material will determine which is the most preferable industrial processing and which Medical Cannabis final product will be manufactured. For example, a high concentration of CBG and CBD in the starting material will be difficult when it comes to separation via supercritical extraction methods.

The accuracy levels of LC (Liquid Chromatography), IR (Infra-red) or GC (Gas Chromatography) Cannabinoids and Terpenoids analysis methods are improved as the sample is more purified. Cannabis flowers are heterogenic so a 5-8% margin of error for mistakes is common. As the samples are more homogenous, the analysis mistake levels go down to 1-2%. The limit of detection is in ~ 0.1% and can be overcome by running the tests in a different range of sample concentrations.

GC and HPLC must have reliable CRM’s for their calibration curves. Today you can get CRM’s from RESTEK or Cerilliant. The ability to detect and quantify Cannabinoids and Terpenes is determined by the sensitivity and the resolution of the method.

Simple analytical methods can be used for the identification of major Cannabinoids, THC, CBD, CBN, and their acidic forms, while more sophisticated analysis methods will be used for minor Cannabinoids analysis and detection.

Cannabis Pesticides and Herbicides

Like any other agricultural crop or product, Cannabis plants and materials should also meet pesticides and herbicides release specifications.

Cannabis may pose a greater risk, due to the fact it is usually consumed via heating and inhalation and goes from the lungs into the bloodstream by smoking or evaporation. Pesticide and Herbicide detection and analysis is very challenging due to the complexity of Cannabis material and is usually performed using GCMS (Gas Chromatography-Mass Spectrometry). Several Pesticides and Herbicides are considered to resemble Cannabinoids’ polarity and boiling points (temperature) and might build up as the process tends to isolate specific Cannabinoids. Pesticides and herbicides can be detected at low PPM levels and may require a more complex sample preparation method.  Cannabis pesticides and herbicides method preparation are usually performed by quenchers kits, or by SPE to pre-purify the sample prior to injection into the relevant analysis system.

Cannabis Microbiological screening

Medical Cannabis is commonly used for HIV, cancer and other medical conditions where the patient’s immune system is “knocked out”. High microbial levels and pathogenic micro-organism or toxins metabolites in the product may risk patients lives. Several fungus types, especially black fungus, Mycotoxins should be detected and analyzed as part of Cannabis release specifications and Quality Control.  Microbiological screening utilizes generic methods developed and used in the food and pharmaceutical industries. Mycotoxins are harmful at the PPB level and the sample preparation is relatively complex. After the matrix has been extracted and filtered, and then tested via HPLC and GC with detection limits around 2-5 ppb, or by ELISA antibody kits with the detection limits down to single ppt’s.

Residual solvents

In cases where solvents were used as part of the cannabis products processing, such as in the extraction stages, solvent residuals in the final product should meet acceptable criteria. The FDA already published the criteria for residual solvents in API’s for pharmaceutical use. The solvent limits are between single PPMs and up to 0.5% by weight. Due to the fact that in the past decade, Cannabinoid formulations contain a high concentration of API’s, 500-1500 mg’s per day, Cannabis product manufacturers have to extend caution so as not to exceed the daily intake limit and the maximal quantity of solvents allowed for a daily dose.

Heavy metals

As with many other plants, Cannabis draws metals from the ground. Elemental impurities also tend to accumulate during the extraction and purification process. Metal traces analysis is performed by ICP.  The tests are usually performed for Mercury, Arsen, Lead and Cadmium and their limit depends on the Cannabis product administration route. For oral administration, the limits are 0.5 ppm for Cadmium and lead, 1.5 ppm for inorganic Arsen and 3 ppm for inorganic Mercury.


Cannabinoid concentrations such as THC, THCa, CBD, CBDa, CBN, CBC, CBG, and many others should meet the concentration ranges specified on the product label, based on the Cannabis product usage purpose, recreational or medical, patients medical condition, age, etc. Cannabinoid concentrations can be tested using HPLC and LCMS.


In addition to their contribution to Cannabis taste and aroma, it is well known that Terpenes increase Cannabinoids’ therapeutic effects, receptor affinity and also have their own health benefits. Terpenes can be detected using GC (Gas Chromatography).

Cannabis analytical testing standardization and validation

In order to meet the regulatory requirements and to produce safe, effective and high-quality Cannabis products for recreational and medical usage, Cannabis testing Quality Control (QC) labs have to standardize and validate their analytical, physical and microbial test methods. Except for QC laboratory’s Quality System establishment, relevant standard operating procedure should be written, trained and followed, testing equipment and methods should be validated. Validation of test methods will assure specificity, linearity, accuracy, reliability, and robustness of the method. These methods will usually validate – as part of the production process validation – and will improve final product credibility. Standardization and validation are the key elements for Cannabis product quality control, in-process controls as well as for final product release.

Cannabis product manufacturing process control, standardization, and quality

The following steps are recommended to be implemented in order to standardize the Cannabis products manufacturing processes:

  • Define the correct batch size, critical process parameters, and in-process regulations
  • Define sampling and testing procedures and frequencies.
  • Validate process and testing equipment and analytical methods
  • Document all manufacturing, sampling, and testing methods in SOPs.
  • Validate sample preparations and testing methods.
  • Acquiring certified reference materials to be used as standards.
  • Set alert and action levels based on test results and risk assessment.
  • Investigation procedure in case of our of specification results and deviations

Procedures should exist for every step of the Cannabis analysis and testing processes. Identification of the same contamination type on each step may require different methods especially for Herbicides and Pesticides GC analysis. (Cannabis plants natural products have chemically resembled contaminates).

Most of the production facilities don’t have an in-house QC laboratory and might need to use external lab services. The external lab must be certified and audited before approval.

Choosing an authorized and certified external lab is a crucial step. Before choosing a QC lab, it is “must” to verify that lab working standards exist and comply with GLP, GMP or ISO 17025 requirements and standards. Before signing a contract, the laboratory should be audited and quality agreement should be signed.

The Quality Control laboratory should hire experienced personnel with the relevant skills and academic background, biology, chemistry, etc. Testing equipment used in the lab should be in a calibrated and validated state and laboratory personnel should follow good documentation and record keeping practices.

It is recommended, especially during the initial stages, to send several Cannabis samples to the same lab to ensure accuracy, consistency, and repeatability.

The Cannabis industry is relatively new for most of the QC labs, and testing methods are being improved and changed frequently.  Having experienced analytical chemists and technicians may be helpful in cases of troubleshooting, new analytical methods development, out of spec. results etc.

About Cannabis GxP consultancy

Cannabis GXP is proud to stand at the forefront of the Cannabis industry in Israel and worldwide thanks to many years of experience in these areas.

Our team is compelled to spread the message of the importance of cannabis science, regulation and standardization as the world enters a new era of cannabis legislation.

We aim to position our clients with their best foot forward when it comes to anything and everything cannabis related.

Our vast expertise allows us to assist companies in a wide range of services and needs: Anything from Cannabis R&D, growing and manufacturing, new products development, facility design, technology, Quality Assurance, Good Practices (GAP/GMP/GLP/GDP/GCP), staff training, local and global regulations.

Cannabis GxP is a subsidiary company of Bio-Chem Ltd. (2007), a consultancy firm for the Pharmaceutical field, medical devices, Cosmetics and food supplements industry based in Israel.

Our cannabis consultancy services include:

  • Product development, delivery system & clinical trials
  • Growing, Manufacturing and Lab Facilities Design
  • Quality Assurance and Good Practices (GxP)
  • Cultivation & Product Manufacturing Technology
  • New product Regulations and Submissions
  • Qualification & Validation
  • Risk Assessment
  • Staff training

If you need one or several of our services, we will be more than happy to assist.

Please do not hesitate to contact us for further information.