关键词: 乙二胺四乙酸(EDTA), 减量滴定法, 肉类食品, 镉测定

Abstract:

A new method for the rapid determination of cadmium content in meat foodstuffs by EDTA decrement titration was developed. Samples were digested with a mixture of HNO3 and H2SO4 (2:1, V/V), and one portion of the digestion solution was added with thiourea to mask Hg2+ at pH 5－6 prior to EDTA titration of total metal ions with xylenol orange as the indicator. Cd2+ in another portion was masked by the addition of KI, and other ions except Cd2+ in the solution were titrated by standard EDTA solution. Finally, the amount of cadmium was calculated though the volume difference of EDTA solution consumed in the titration of two portions. The relative standard deviation of this method was less than 2.0% and the recovery was between 97.8% and 100.2%. It is indicated that the improved method is an easy-operating way with high accuracy and little disturbance, and its results are consistent with those of national standard method

Key words: EDTA, decrement titration, meat foodstuffs, determination of cadmium