Combining ultrasound-assisted extraction and a microliter colorimetric assay for the streamlined determination of urea in animal feedstuff.
This paper proposes a novel analytical strategy for the routine determination of urea in animal feedstuffs, combining an ultrasound-assisted miniaturized extraction protocol with a microplate colorimetric assay based on the reaction between 4-dimethylaminobenzaldehyde and urea. In order to accelerate the extraction, we introduced an ultrasound-assisted miniaturized protocol and compared it with both classic and miniaturized alternatives. The potential interference of amino acids was bypassed by shifting the detection wavelength from 435 to 450 nm. Urea could be quantified in the range 0.05-1.00% (w/w) with high precision (RSD < 5%). The results were in agreement with a commercial enzymatic method, demonstrating the accuracy and selectivity of the assay. The miniaturization led to a 50 times downscale when compared to the official method, resulting in a reduction of at least 90% in chemical consumption per determination, contributing to a more "green" and sustainable analytical methodology.
REQUIMTE, ICBAS, Instituto de Ciencias Biomédicas de Abel Salazar, and ‡REQUIMTE, Departamento de Química Aplicada, Faculdade de Farmácia, Universidade do Porto , Rua Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal.
Hugo M
HM
Oliveira
Marcela A
MA
Segundo
António J M
AJ
Fonseca
Ana R J
AR
Cabrita
D000821:Animal Feed / Q000032:analysis*; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D003124:Colorimetry / Q000379:methods*; D014465:Ultrasonics / Q000379:methods*; D014508:Urea / Q000032:analysis*
D014508:Urea