Hanna Instruments HI934 Bedienungsanleitung Seite 108

3
HI9001EN TITRATOR VALIDATION WITH 1.0 mg/g WATER STANDARD
DESCRIPTION
Method for the validation of the titrator accuracy. The
results should be within the uncertainty limits specified
by the manufacturer of the standard. The results are
expressed in mg/g.
ELECTRODE
• HI76330 Dual Platinum Pin Electrode
• HI900517 Generator with Diaphragm
-or-
• HI900512 Generator without Diaphragm
REAGENTS
• General Purpose Coulometric Karl Fischer Reagent
• 1.0 mg/g Liquid Water Standard
ACCESSORIES
• 3 mL syringe (clean and dry)
• 22-gauge, 6" non-coring septum penetration needle
(clean and dry)
• Solvent bottle, GL45 thread
DEVICE PREPARATION
• Connect the reagent bottle top assembly to the bottle
of reagent according to the manual.
• Assemble the titration vessel according to the
instruction manual.
• Press
keys to highlight HI9001EN Validation - 1.0 mg/g
Std and press
• Dispense enough reagent from the reagent bottle to
fill the vessel to the "min" line (about 75 mL).
• Press
titration vessel moisture. Allow the background drift
rate to stabilize before proceeding to the next step.
3-2
from the main screen. Use the arrow
.
key to pre-titrate the reagent and the
ANALYSIS
• Fill the syringe and needle with the standard. Any
unused standard remaining in the ampoule should
be disposed in order to avoid contamination from
atmospheric water.
• Weigh the syringe, needle and standard.
• Press . You will be prompted to enter the
sample size.
• Dispense 1.00 g (approximately 1 mL) of standard
into the titration vessel through the septum using
the needle.
• Pay attention not to get any standard on the electrode
or beaker walls. If necessary, swirl the titration
vessel gently by hand to remove any standard from
the electrode or beaker wall.
• Clear the needle of residual standard by intaking a
small volume of air from the titration vessel. If a
"hanging drop" of standard is seen on the end of
the needle, dip the end of the needle briefly in the
reagent.
• Remove the needle from the titration vessel and
weigh the syringe again in order to determine the
added standard mass (by difference of the two
measurements.)
• Use the numeric keypad to enter the exact weight
and press key to start the analysis.
• At the end of the titration, the Sample Analysis
Result screen is displayed. The results are expressed
in mg/g.