High-Throughput Analysis of Mycotoxins in Cannabis CBD Oil Pairs Simplified Cleanup with LC-MS/MS Sensitivity

• Fast, 3-min total cycle time lets you analyze more samples per shift.
• Resprep SPE sample cleanup removes matrix interferences in one simple step.
• Excellent sensitivity down to 2 ng/g in matrix on legacy instrumentation.

Aflatoxins and ochratoxins are an emerging concern in the cannabis industry as these secondary fungal metabolites can cause disease and death if consumed. Crops are susceptible to fungal growth from seed through storage, so there are many opportunities for contamination to occur. As a result, a growing need is emerging for testing to detect the presence of mycotoxins in both raw plant materials and finished cannabis products in order to protect consumer health and safety. The analysis of mycotoxins in cannabis oils is particularly challenging because the lipids in the sample can contribute isobaric matrix interferences in addition to general ion suppression that can reduce accuracy, particularly at low levels.

Immunoaffinity columns (IACs) are commonly used for sample preparation when analyzing mycotoxins in cannabis; however, IACs also contribute significantly to the overall complexity, time, and cost associated with mycotoxin analysis. IAC methods are labor intensive, requiring numerous conditioning and washing steps. In addition, labs typically have to use multiple IACs in order to analyze all the mycotoxins of interest due to columns being specific for aflatoxins or ochratoxins.

In this study, a simple pass-through SPE sample cleanup was developed as an alternative to IACs and applied to lipid-rich CBD oils. Excellent chromatographic results were obtained for both aflatoxins and ochratoxins even at 2 ng/g, indicating that the simplified sample prep technique effectively removed lipid interferences. The SPE sample cleanup was paired with a rapid LC-MS/MS analysis utilizing a Raptor Biphenyl column. The polarizability and unique selectivity of the Raptor Biphenyl column effectively separated all target analytes in a fast, 3-minute analysis, making this method a better approach than IACs for high-throughput testing of mycotoxins in cannabis CBD oils.

	Peaks	tR (min)	Precursor Ion	Product Ion 1	Product Ion 2
1.	Aflatoxin G2-13C17	1.340	348.3	330.3	-
2.	Aflatoxin G1-13C17	1.576	346.3	257.3	-
3.	Aflatoxin B2-13C17	1.703	332.3	303.3	-
4.	Ochratoxin A	1.824	404.3	239.1	358.3
5.	Ochratoxin A-13C20	1.825	424.3	250.2	-
6.	Aflatoxin B1-13C17	1.947	330.3	301.4	-

Column	Raptor Biphenyl (cat.# 9309A52)
Dimensions:	50 mm x 2.1 mm ID
Particle Size:	2.7 µm
Pore Size:	90 Å
Guard Column:	Raptor Biphenyl EXP guard column cartridge 5 mm, 2.1 mm ID, 2.7 µm (cat.# 9309A0252)
Temp.:	35 °C
Standard/Sample
Diluent:	45:55 Water:Methanol
Inj. Vol.:	5 µL
Mobile Phase
A:	Water, 2 mM ammonium formate, 0.1% formic acid
B:	Methanol, 2 mM ammonium formate, 0.1% formic acid
	Time (min) Flow (mL/min) %A %B 0.00 0.7 35 65 2.00 0.7 10 90 2.01 0.7 35 65 3.00 0.7 35 65

Detector	MS/MS
Ion Mode:	ESI+
Mode:	MRM
Instrument	UHPLC
Sample Preparation	0.25 g of commercially available hemp-derived CBD oil was weighed into a 2 mL vial. A working internal standard was prepared using 13C labeled analogs at a concentration of 250 ng/mL in methanol. 10 µL of the working internal standard was aliquoted into the sample followed by vortexing for 10 seconds at 3000 rpm. 1 mL of 45:55 H2O:MeOH was added to the sample. The sample was vortexed for 30 seconds at 3000 rpm. The sample was then centrifuged at 3000 xg for 5 min at 10 °C. 750 µL of the supernatant was transferred to a conditioned (1 mL 45:55 water:methanol) Resprep bonded reversed phase SPE cartridge (Restek cat.# 26030). The sample was pulled through under vacuum into an autosampler vial for LC-MS/MS analysis.
Notes	Want even better performance when analyzing metal-sensitive compounds? Check out Inert LC columns at www.restek.com/inert.

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Want even better performance when analyzing mycotoxins and other metal-sensitive compounds? Learn more at www.restek.com/inert