Analytical Chemistry

(4) The solution prepared in question 3 was used to investigate the effect of the matrix on the
measurement of nickel. Five aliquots (10 cm^3 ) of the steel solution were measured out and standard
amounts of nickel added to each. The volume of each was then adjusted to 20.0 cm^3. When these
solutions were measured the following results were obtained.

Solution Added Ni concentration in

solution/ppm

Absorbance

1 2 0.260

2 4 0.383

3 6 0.510

4 8 0.635

5 10 0.762

Calculate the concentration of nickel in the stainless steel according to these data. Suggest an
explanation for any difference from the value obtained in question 2.

(5) Contrast the type of information obtainable in the determination of trace metals by X-ray
fluorescence and electron probe analysis.