eutech-instruments bromide epoxy Manuale Utente
Instruction Manual
Bromide Electrode
7
A calibration curve is constructed on semi-logarithmic paper when using a
pH/mV meter in the millivolt mode. The measured electrode potential in
mV (linear axis) is plotted against the standard concentration (log axis). In
the linear region of the curve, only three standards are necessary to
determine a calibration curve. In the non-linear region, additional points
must be measured. The direct measurement procedures given are for the
linear portion of the curve. The non-linear portion of the curve requires the
use of low level procedures.
pH/mV meter in the millivolt mode. The measured electrode potential in
mV (linear axis) is plotted against the standard concentration (log axis). In
the linear region of the curve, only three standards are necessary to
determine a calibration curve. In the non-linear region, additional points
must be measured. The direct measurement procedures given are for the
linear portion of the curve. The non-linear portion of the curve requires the
use of low level procedures.
6.
To a clean, dry 150 ml beaker, add 100 ml of the sample and 2 ml of ISA. Place the beaker
on the magnetic stirrer and begin stirring at a constant rate. Rinse the electrode tips with
distilled water, blot dry and lower into the solution. When the reading has stabilized,
record the mV reading. Using the calibration curve, determine the concentration directly
from the calibration curve.
on the magnetic stirrer and begin stirring at a constant rate. Rinse the electrode tips with
distilled water, blot dry and lower into the solution. When the reading has stabilized,
record the mV reading. Using the calibration curve, determine the concentration directly
from the calibration curve.
7.
The calibration should be checked every two hours. Assuming no change in ambient
temperature, place the electrode tips in the mid-range standard. After the reading has
stabilized, compare it to the original reading recorded in Step 3 above. A reading differing
by more than 0.5 mV or a change in the ambient temperature will necessitate the repetition
of Steps 2-5 above. A new calibration curve should be prepared daily.
temperature, place the electrode tips in the mid-range standard. After the reading has
stabilized, compare it to the original reading recorded in Step 3 above. A reading differing
by more than 0.5 mV or a change in the ambient temperature will necessitate the repetition
of Steps 2-5 above. A new calibration curve should be prepared daily.
Direct Measurement of Bromide (using an ion meter)
1.
By serial dilution of the 0.1M or 1,000 ppm bromide standard, prepare two standards
whose concentration is near the expected sample concentration. Measure 100 ml of each
standard into individual 150 ml beakers and add 2 ml of ISA to each.
whose concentration is near the expected sample concentration. Measure 100 ml of each
standard into individual 150 ml beakers and add 2 ml of ISA to each.