Method for colorimetric analysis of water content

A method for determining water content of an unknown sample by the Karl Fischer method, using the steps of:

• measuring the optical density of a known volume of an iodione-containing Karl Fischer reagent and a dye at a first wavelength at which iodine strongly absorbs while the dye absorbs at most, only minimally,
• measuring the optical density of said known volume at a second wavelength at which the dye strongly absorbs while iodine absorbs at most, only minimally,
• adding the sample to said known volume to create a new volume of iodine-containing Karl Fischer reagent, dye, and sample, the sample reacting with the iodine-containing reagent in accordance with a Karl Fischer type reaction,
• measuring the optical density of said new volume of iodine-containing reagent, dye, and sample at said first wavelength, the change in optical density at first wavelength, the change in optical density at said first wavelength being related to the amount of water in the sample,
• measuring the optical density of said new volume of iodine-containing reagent, dye, and sample at said second wavelength, the change in optical density at said second wavelength being a correction to the change in optical density at said first wavelength, and
• determining the water content of the sample by applying said correction to the change in optical density at said first wavelength.