GF-AAS Determination of Chromium in Feed with Microwave Assisted Sample Digestion

A method of GF-AAS for the determination of Cr in feed was proposed.The sample was treated by microwave assisted digestion with HNO3 and H2O2.Ammonium dihydrogen phosphate was used as matrix modifier.The ashing and atomization temperature for Cr were taken at 850 ℃ and 2 600 ℃ respectively.Under the optimum conditions,linear relationship between values of absorbance and mass concentration of Cr ranged within 40.0 μg·L-1 was obtained.Detection limit (3S/N) of the method was 0.004 μg·kg-1.Tests for recovery and precision were tested by addition of 5.00 mg·kg-1,10.00 mg·kg-1 and 15.00 mg·kg-1 of standard solution,and analyzed by the proposed method,values of recovery in the range of 97.4%-101.2% and values of RSD (n=5) less than 6.5% were obtained.