A set of 25 wheat flour laboratory samples and 1 certified reference
material (NIST SRM 1567a, Wheat Flour) were used for method development
and validation. Samples were acquired in local markets of
Piracicaba (São Paulo State) and Viçosa (Minas Gerais State), Brazil.
Laboratory samples were homogeneously mixed with 30% mm−1
cellulose (SPEX 3642 Cellulose Binder, USA) in a cryogenic mill (Spex
6800 Freezer Mill, USA), with a self-container liquid nitrogen bath.
After 5 min pre-cooling, the samples were homogenized for 30 min
(15 cycles of 2 min), with 1 min re-cooling between cycles. Alternative