Hanna Instruments HI 904 - Manual (Page 70)

5-12
METHODS
5.5.9 Sample Parameters
This screen allows the user to access and configure the specific sample parameters.
5.5.9.1 Sample Determination
This screen allows the user to select the sample determination mode.
Normal sample determination is performed through direct titration of liquid samples that are
soluble in solvent and have homogeneous distribution in water.
External extraction is a method for the preparation of insoluble samples that require a water
extraction. Using the proper solvents, the sample is broken down into a fine suspension from
which the water is extracted and released into the solvent.
External dissolution is a method for the preparation of the following types of samples:
• samples with a very high water content.
• samples that do not exhibit a homogeneous water distribution.
• slow-dissolving samples.
• samples that can contaminate the titration vessel, thus reducing the accuracy, preci-
sion, number of titrations between solvent changes and raising the cell maintenance
requirements.