Spectrophotometric Determination of Trace Chromium in Food Samples

摘要

A novel spectrophotometric method for the determination of trace amount of Chromium (VI) by tri-hydroxyl 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 8.99times10⁴ L/mol/cm. Beer's law is obeyed over the range of 0 ~ 0.7 mug/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%.