61. Option 2 A sample of animal tissue weighing m g was

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61. Option 2
A sample of animal tissue weighing m g was burnt in a muffle furnace, the residue was dissolved in HCl and diluted with a solution of lanthanum salt to 5.00 ml to eliminate the interfering influence of phosphate ions.
Equal volumes of standard calcium solutions containing С0 = 0 were added to four equal portions of the analyzed solution; C1 = 2.0; C2 = 4.0; C3 = 8.0 µg / ml Ca and the same amount of lanthanum salt as in the analyzed solution. The atomic absorption spectrophotometer measured the optical density of the analytical line of calcium (422.67 nm)
Calculate the concentration of calcium (mg / kg) in the following samples, using the construction of the calibration curve using the method of additives:
Option 2
m = 0.20 g
Atomic absorption
Ax / 2 = 0.075
A (x + C1) / 2 = 0.150
A (x + C2) / 2 = 0.226
A (x + C3) / 2 = 0.380