PPM = (solute mass ÷ solution mass) × 1,000,000
PPM = (solute volume ÷ solution volume) × 1,000,000
PPM = (mass of solute in mg ÷ mass of solution in kg)
PPM = (number of parts ÷ total parts) × 1,000,000
For dilute aqueous solutions, PPM ≈ mg/L
Convert all quantities to the same units before calculating
Divide the amount of solute by the total amount of solution
Multiply the result by 1,000,000