2.4. Sample preparation
The sausages were air dried and grinded. Then 10 g of each sample
was weighed and placed in a beaker, and 5 mL of borax solution (5%)
and 150 mL of hot water were added and placed in a hot water path
(80–90 °C) for 30 min. The clarification of the extract was conducted by
addition of the Carrez reagent (2 mL of hexacyanoferrate, 0.25 mol L
−1
of potassium (II) aqueous solution and 2 mL of 0.25 mol L
−1
zinc
acetate aqueous solution) followed byfiltration through filter paper.
Thefiltrate was further diluted to obtain the desired concentrations of
nitrite[20].