Spectrophotometric Determination of Trace Chromium in Food Samples

摘要

A novel spectrophotometric method for the determination of trace amount of Chromium (Ⅵ) by Trihydroxyl phenylfluorone (THPF) in the microemulsion medium has been developed. All the variables were studied in order to optimize the reaction conditions. At pH=5.82, Cr(Ⅵ) reacts with THPF to form a 1:2 complex, which has a maximum absorption at 560 nm with a molar absorptivity of 8.99×104 L/mol/cm. Beer's law is obeyed over the range of 0～0.7 μg/mL of Cr(Ⅵ). The method is highly sensitive and has been applied in determination of Cr (Ⅵ) in food samples with satisfactory results. The relative standard deviation is less than 1.1% and the recovery is 96.7～106%.