Heavy Metal Analysis via ICP/MS
ICP/MS analysis is used in hemp testing so as to ensure that the product, be it plant or oil, contains acceptable amounts of trace heavy metals. There is currently no set standard for heavy metal testing in hemp, so the procedural standards set below are adopted from the CT regulations on medical marijuana.
The technique of ICP/MS is relatively straightforward for no matter what sample is being utilized so long as the technician is properly trained with the instrument. It is imperative that proper sample preparation does occur, which is included below, and that proper technique is followed.
For the case of Incredible Edibles, we are currently only interested in the testing of CBD hemp oil so as to ensure the quality of the product that we produce with it, for the peace of mind, health, and safety of our customers.
ICP/MS Sample Preparation
Sample preparation of any solid for ICP/MS analysis requires proper digestion of the sample in strong and hot acids. However, as there is only CBD oil being tested for heavy metals, this will be unnecessary. It should be of note that CBD in MCT oil will likely need to be diluted during sample preparation to avoid precipitation in the nebulizer and/or overloading the plasma. Other ways that can deal with the TDS being >0.5% include specialized nebulizers and spray chambers, but sample dilution is the easiest step.
In the future, there may be a need to test heavy metals in hemp plant material. This is due to C. sativa being a very good plant for ground remediation, and it will sequester many heavy metals. In such a case, the plant material would require proper digestion methods, outlined in a protocol by Agilent here.
ICP/MS Testing Requirements for Hemp
The requirements for trace heavy metals in hemp set forth by Incredible Edibles, as adopted from the Regulations of Connecticut State Agencies for Medical Marijuana, are as follows:
Arsenic < 0.14 μg/kg
Cadmium < 0.09 μg/kg
Lead < 0.29 μg/kg
Mercury < 0.29 μg/kg
(Sec. 21a-408-58. Laboratory testing)
These standards are apt to change quickly, especially with incoming FDA regulations and more intense medical research on hemp consumption.
There are available broad-spectrum standards for ICP testing available from Sigma-Aldrich, depicted below. These are likely overkill for the time being, and standards for As, Cd, Pb, and Hg should be generally available.
