Question

i. NIST-traceable standard metal ion solutions are provided. The standard metal ion solutions are each 1000 ppm. Compute how much of the NIST-traceable solution you will use to prepare 100 mL of a

Answer 1

i. Solution

Dilution Formula = M1V1 = M2V2

Where, M1 = molar concentration (ppm) of Standard solution ; V1 = volume of standard solution ; M2 = molar concentration (ppm) of solution to be made ; V2 = volume of solution to be made

To make up 100 mL of 10 ppm from 1000 ppm standard metal ion solution

10 x 100 / 1000 = 1.0 mL

i.e. 1.0 mL of 1000 ppm in 100 ml volume will give a 10 ppm solution. This solution will be referred to as the "stock" standard here onwards.

ii. Solution

[A] Now let us make different concentrations of Calcium (ppm) solutions.

(a) To make up 10 mL of 0.1 ppm from 100 ppm "stock" standard solution

0.1 x 10 / 100 = 0.01 mL

i.e. 0.01 mL of 100 ppm in 10 ml volume will give a 0.1 ppm solution

(b) To make up 10 mL of 0.5 ppm from 100 ppm "stock" standard solution

0.5 x 10 / 100 = 0.05 mL

i.e. 0.05 mL of 100 ppm in 10 ml volume will give a 0.5 ppm solution

(c) To make up 10 mL of 1.0 ppm from 100 ppm "stock" standard solution

1.0 x 10 / 100 = 0.1 mL

i.e. 0.1 mL of 100 ppm in 10 ml volume will give a 1.0 ppm solution

(d) To make up 10 mL of 2.0 ppm from 100 ppm "stock" standard solution

2.0 x 10 / 100 = 0.2 mL

i.e. 0.2 mL of 100 ppm in 10 ml volume will give a 2.0 ppm solution

(e) To make up 10 mL of 5.0 ppm from 100 ppm "stock" standard solution

5.0 x 10 / 100 = 0.5 mL

i.e. 0.5 mL of 100 ppm in 10 ml volume will give a 5.0 ppm solution

[B] Now let us make different concentrations of Magnesium (ppm) solutions.

(a) To make up 10 mL of 0.1 ppm from 100 ppm "stock" standard solution

0.1 x 10 / 100 = 0.01 mL

i.e. 0.01 mL of 100 ppm in 10 ml volume will give a 0.1 ppm solution

(b) To make up 10 mL of 0.2 ppm from 100 ppm "stock" standard solution

0.2 x 10 / 100 = 0.02 mL

i.e. 0.02 mL of 100 ppm in 10 ml volume will give a 0.2 ppm solution

(c) To make up 10 mL of 0.5 ppm from 100 ppm "stock" standard solution

0.5 x 10 / 100 = 0.05 mL

i.e. 0.05 mL of 100 ppm in 10 ml volume will give a 0.5 ppm solution

(d) To make up 10 mL of 1.0 ppm from 100 ppm "stock" standard solution

1.0 x 10 / 100 = 0.1 mL

i.e. 0.1 mL of 100 ppm in 10 ml volume will give a 1.0 ppm solution

(e) To make up 10 mL of 2.0 ppm from 100 ppm "stock" standard solution

2.0 x 10 / 100 = 0.2 mL

i.e. 0.2 mL of 100 ppm in 10 ml volume will give a 2.0 ppm solution