Question

9) In a study of the poisoning of fish, 0.500 g of samples of fish tissue were analysed for barium. Each sample was digested with a permanganate-sulfuric acid mixture, and the volume adjusted to 10 mL and to construct calibration curve, 0.500-g samples of uncontaminated fish tissue were injected with various amounts of Ba+2, and corresponding absorbance as follows:

Standard 0: 0.00μg Ba+2; 0.015
Standard 1: 50 μg Ba+2; 0.220
Standard 2: 100 μg Ba+2; 0.415
Standard 3: 150 μg Ba+2; 0.602


If all samples and standards were treated in identical manner, what was the concentration of barium (in μg Ba per g of fish) in a fish sample whose absorbance value was 0.421 and 0.378, respectively?