Pesticide Residue Analysis With GC-MS/MS
What is pesticide residue analysis?
The use of pesticides can help increase agricultural product yields by killing harmful bugs, fungi, and weeds. When crops, such as cannabis flower, are harvested, there may be a small amount of pesticide residue that remains on the crop. The goal of
pesticide residue analysis is to determine which pesticides are present on the product, the amount of each detected pesticide, and whether that amount is below regulatory limits.
Why is pesticide residue analysis important?
Just as pesticides are harmful to unwanted pests, they can also be harmful to pollinators, such as honeybees, and even humans in large enough doses. While not an exhaustive list, possible side effects can include nervous system damage, hormone imbalances, and skin irritation, depending on the pesticide. Some pesticides may even cause cancerous cells to develop (carcinogens). As such, it is important to know which pesticide residues are on the crop, how much is present, and if that amount poses a substantial risk to human and environmental health.
What is the permissible amount of pesticide residue for cannabis products?
The acceptable limits for each pesticide depend heavily on the type of crop and the jurisdiction; for cannabis, however, some limits can be as low as 10 ppb. Some cannabis samples may be diluted by a factor of ten during extraction and clean up, so the measurement technique needs to be able to detect some pesticides at 1 ppb.
Pesticides are divided into different sub-groups depending on their chemistry. Because there are so many different kinds of pesticides, it is difficult to do pesticide residue analysis with just one technique. The most common techniques involve chromatography, which separate the pesticides before they are detected. Gas chromatography-mass spectrometry (GC-MS) and liquid chromatography mass spectrometry (LC-MS) are the two techniques used for the bulk of pesticide residue analysis. Other techniques, such as
direct analysis in real time (DART), can be used to detect pesticides, but they may not be able to measure at the levels necessary for regulatory agencies.
How is pesticide residue measured?
Before pesticide residues can be measured, a sample suitable for analysis must be prepared. Typically, sample preparation involves two steps:
extraction of the pesticides from the crop into a solvent, and then clean-up of the sample to remove unwanted chemicals that can interfere with the analysis. The QuEChERS (quick, easy, cheap, effective, rugged, safe) extraction, followed by dispersive solid phase extraction (dSPE) cleanup, is an excellent way to do both steps in a single sample preparation method. Once the sample has been prepared, it needs to be measured by a suitable technique that can identify which pesticides are present and in what quantities.
What methods can be used for pesticide residue analysis?
A
triple-quad mass spectrometer, a tandem mass spectrometry (MS/MS) technique, has the added benefit of selectively monitoring each pesticide as it passes into the mass spectrometer, while filtering out chemicals that could interfere with the measurement. This is especially important when dealing with a complex matrix, such as cannabis. The result is excellent detection of pesticide residues at low levels. Furthermore, measuring specific parts of each pesticide provides additional confirmation of each pesticide’s identity.
Why is the JEOL Triple Quad Mass Spectrometer the ideal tool for pesticide residue analysis of cannabis products?
The
JEOL JMS-TQ4000GC triple quad mass spectrometer uses patented technologies to improve the timing for measuring different pesticides simultaneously and increasing sample accumulation prior to detection. Both of these tools improve the overall performance and increase the number of pesticides that can be measured at 1 ppb, which would benefit any laboratory doing residual pesticide analysis on cannabis products.
As legalizing cannabis use becomes more widespread, there will be an increased need for residual pesticide analysis and
terpene profiling. Triple-quad mass spectrometry coupled with a gas chromatography is an excellent technique for measuring residual pesticides in a complex matrix due to its selectivity and sensitivity. The JEOL JMS-TQ4000GC offers excellent performance for residual pesticide analysis, and can meet or exceed the 1 ppb limit for several pesticides. For more information,
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