Analysis of 10 mycotoxins in different agricultural and food/feed matrices using LS-MS/MS

In this study, a multi-mycotoxin analysis method based on solid-liquid extraction (SLE) for the analysis of aflatoxins (AFB1, AFB2, AFG1, AFG2), deoxynivalenol (DON), fumonisin B1 (FB1), fumonisin B2 (FB2), ochratoxin A (OTA), T-2 toxin, and zearalenone (ZEN) in various agricultural (corn, wheat, barley, wheat bran, soy bean, sunflower seed) and food/feed matrices (compound feed for pigs and poultry and total mixed ration for dairy cows) was developed and validated using LC-MS/MS Triple Quadrupole (Waters Xevo TQ-XS) at Betagro Science Center, Thailand.

The samples were finely ground and homogenized using a laboratory mill, and 2.5 g of sample was weighed and placed in a conical tube.

⇒ To this tube, 10 ml of extraction mixture I (80 % acetonitrile:19.9 % water:0.1 % formic acid) was added, and the lid was closed.

The tube was then placed on an orbital shaker at 230 rotations per minute (rpm) for thorough mixing (90 minutes at room temperature).

The tube was subsequently centrifuged at 4000 × g for 5 minutes at 4 °C, and the supernatant was transferred to another 50 ml tube.

Then, 500 µl of supernatant was pipetted and combined with 500 µl of diluent solvent (50 % acetonitrile:0.1 % formic acid) in a 15 ml tube, and the solution was mixed by vortexing for 30 s.

To compensate for matrix effects during electrospray ionization, mixed 13C-labelled internal standards for aflatoxins (AFB1, AFB2, AFG1, AFG2), deoxynivalenol (DON), fumonisin B1 (FB1), fumonisin B2 (FB2), ochratoxin A (OTA), T-2 toxin, and zearalenone (ZEN) were pipetted (20 µl) into 1000 µl of the extract contained in the 15 ml tube, and the solution was mixed by vortexing for 30 s.

A total of 1020 µl of liquid was prepared by filtering the extract through a membrane syringe filter into a glass vial for LC-MS/MS analysis.

The recoveries of 10 mycotoxins spiked in food/feed and cereal matrices were recorded in the range of 93.6 %-114.2 % after internal standard correction (relative standard deviations [RSDs] below 14.2 %).