Preparation of Standard Solutions
Dry reagent grade sodium chloride at 100 °C overnight. Allow sample to come to room
temperature in a desiccator. Prepare 100 mL of stock solution containing about 1000 ppm of
sodium. Dilute this to prepare a ~100 ppm working standard. From this, prepare series of
standard solutions of concentration ~1, 2, 4, 6, 8, and 10 ppm in Na respectively. Ensure all
solutions are tightly stoppered. Calculate the exact concentration of the stock solution.