97. Solving a chemistry problem

5. Calculate the detection limit for the photocolorimetric determination of iron(III) with sulfosalicylic acid in an ammonia medium. The thickness of the absorbing layer is 5 cm, the minimum volume of the photometric solution is 15 ml. The molar coefficient of light absorption of the complex (blue light filter) is 4000. The minimum optical density measured by the device is 0.01.
Answer: 0.4 mcg