Hanna Instruments HI 903 - Manual (Page 99)

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TITRATION
Manual Entering
Follow the steps below:
Sample size by mass :
1. Measure the mass of the sample in a weigh boat or syringe.
2. Slide the sample plug up out of the vessel top to open the sample port, or insert
the syringe needle through the septum.
3. Rapidly add the sample through the sample port ensuring that ALL of the sample is
transferred to the solvent. Avoid any contact between the sample and the cell
cover.
4. Replace the sample plug into the cell cover, or remove the syringe from the septum.
5. Determine the mass of the ‘empty’ weigh boat or syringe.
6. Calculate the mass of the sample added (subtract the mass of the emptied weigh
boat or syringe from the mass of the full weigh boat or syringe).
7. Enter the calculated mass of the sample.
Sample size by volume :
1. Attach a long needle (approximately 6 cm for best control) to a precision-volume
syringe large enough to hold at least one complete sample volume.
2. Rinse the syringe and needle with sample several times by drawing in a small
portion of sample, fully extending the plunger, shaking to coat the syringe interior
and expelling the sample into a waste collection container.
3. Draw enough sample into the syringe for at least one titration.
4. Dry the outside of the needle with a lint free wipe or tissue.
5. Insert the needle through the septum in the sample port. Push the syringe through
the septum until the end of the needle is approximately 1 cm from the surface of
the solvent.
6. Steadily dispense the appropriate volume of sample ensuring that the sample is
introduced directly into the solvent and does not splash or spatter onto the wall of
the titration vessel, electrode, or dispensing tip.
7. Draw a small amount of air from inside the cell into the syringe to ensure that no
sample drops remain on the tip of the needle.
8. Remove the syringe and needle from the septum taking care to not touch the
needle to the solvent or other internal cell components.
9. Enter the calculated mass of the sample.
Sample size by pieces :
1. Enter the number of pieces that were added to the titration vessel.