Pickering Labs - Analysis of Mycotoxins in Hemp and Hemp-Containing Edible Products

Pickering Laboratories developed an easy and sensitive method to analyze aflatoxins B1, B2, G1, G2, and ochratoxin A in hemp and hemp-containing edible products. Mycotoxins are isolated using immunoaffinity clean-up columns and analyzed with fluorescence detection. To increase sensitivity of aflatoxins B1 and G1, an in-line photochemical reactor (UVE™) is installed before the detector. This method utilizes standard HPLC equipment and allows laboratories to easily determine these mycotoxins at low ppb levels.

Figure 1: Chromatogram of hemp pre-roll spiked with 6.5 ng/g of aflatoxin B1; 1.8 ng/g of aflatoxin B2; 6.1 ng/g of aflatoxin G1; 1.9 ng/g of aflatoxins G2; and 20.1 ng/g of ochratoxin A.

Method

Isolation of aflatoxins B1, B2, G1, G2, and ochratoxin A

Blend 1 g of finely ground sample with extraction solution (10 mL of methanol/water 80:20) using a handheld homogenizer. Centrifuge for 10 min. Mix 2 mL of the extract with 10 mL of PBS buffer (containing 2% Tween 20). Clean the extracts using AflaOchra HPLC immunoaffinity column (Vicam).

Figure 2: Chromatogram of hemp-containing chocolate spiked with 6.5 ng/g of aflatoxin B1; 1.8 ng/g of aflatoxin B2; 6.1 ng/g of aflatoxin G1; 1.9 ng/g of aflatoxins G2; and 20.1 ng/g of ochratoxin A.

Analytical Conditions

Analytical Column: Mycotox™ (Pickering), C18, 4.6 × 250 mm

HPLC eluent: sodium phosphate buffer (Cat #1700–1108), methanol, acetonitrile

Flow rate: 1 mL/min

Post-column photochemical reactor: UVE (Cat # 10519 (240V), Cat # 10742 (120 V) FLD: Excitation 36 nm, Emission 430 nm for Aflatoxins Excitation 333 nm, Emission 477 nm for Ochratoxin A

Calibration

The 5-point calibration curves were built in the ranges of 0.325–3.25 ppb for B1, 0.088–0.882 ppb for B2, 0.310–3.099 ppb for G1, 0.099–0.996 ppb for G2, and 1–10 ppb for ochratoxin A. Correlation coefficient was R² >0.999 for all toxins.

Pickering Laboratories
1280 Speca Park Way, Mountain View, CA 04043
tel. (800) 654-3330, (650) 694-6700
Website: www.pickeringlabs.com