Cryo-Blade Device Used to Analyze Contamination of Food Samples

In a presentation at the North American Chemical Residue Workshop on Sunday, Steven Lehotay, PhD, residue chemistry and predictive microbiology research chemist at the US Department of Agriculture, presented findings from a study using a cryo-blade device for QuEChERSER sample preparation and both GC-MS/MS and LC-MS/MS analysis of pesticides in grapes, watermelon, and green beans (1). The fruits and vegetables were processed using liquid nitrogen, dry ice, and at room temperature.

“To my knowledge, no other device using liquid nitrogen for sample processing are designed to accommodate the regulatory-mandated 1 kg bulk food sample amount,” Lehotay told LCGC in an email. “This can be done in a 1-step process, even for high-moisture samples like watermelon, without pre-freezing the sample.”

The study, published in Journal of Agriculture and Food Chemistry, showed acceptable consistency of results for test portions as low as 0.5 g.

“Taking small test portions streamlines the subsequent sample preparation steps and saves reagents, space, and cost, but all is wasted if the test portions are not representative of the collected sample from the field,“ Lehotay said. “In our study, the resulting frozen powder was so consistent that even 0.5 g test portions were representative of the original 1 kg sample.”

The cryogenic device also worked well at detecting pesticides when the samples were processed at room temperature, Lehotay continued, adding that, while cryogenic sample processing was still found to be better for some pesticides, room temperature slurry is acceptable in many cases.

Reference

Lehotay, SJ.; Michlig, N.; Lightfield, AR.; Evaluation of a New Cryogenic Device for Comminution of 1 kg Bulk Food Samples for Analysis of Contaminants in < 1 g Test Portions. In Book of Abstracts, 2023 North American Chemical Residue Workshop, Fort Lauderdale, Florida.