Addition method in the proton isoconcentration technique for the determination of water in organic solvents

Abstract

Two analytical procedures were used for the determination of water in organic solvents under proton isoconcentration conditions, based on a large and systematic change in potential measurements with addition of 0–2%m/m of water to a solution of a dry solvent containing 2 × 10^–3 mol dm^–3 perchloric acid in glacial acetic acid as a background electrolyte, using a combination pH glass electrode. The solvents tested were propanone, acetonitrile, sulpholane and propylene carbonate. The first procedure was used directly for the determination of water in the range 0–2%m/m and the second for the range 2–100%m/m. In the second procedure the dilute solvent was concentrated by mixing with a dry solvent. The method is fast, accurate and reproducible.