We studied the optimal composition of EDTA-chelated biuret reagent for the determination of protein in serum. A reagent containing 18 mmol of EDTA, 15 mmol of Cu2+, and 1 mol of NaOH per liter exhibits a very low blank but about the same sensitivity as tartrate-chelated reagents. Maximum color intensity is attained within 25 min at room temperature, and adheres to Beer's law up to 120 g of protein per liter.
No takes yet. Share an insight, caveat, or question.
Chromý et al. (1974) studied this question.