eutech-instruments sodium glass Manuel D’Utilisation

Instruction Manual

Sodium Electrode

TROUBLESHOOTING HINTS

Symptom

Possible Causes

Next Step

Out of Range Reading

defective meter

check meter with shorting strap
(see meter instruction manual)

defective electrode

check electrode operation

electrodes not plugged in
properly

unplug electrodes and reset

reference electrode not filled

replenish reference filling solution

electrodes not in solution

put electrodes in solution

air bubble on redipping
electrode

remove bubble by membrane

"Incorrect Answer" (but
calibration curve is
good)

incorrect scaling of semi-log
paper

plot millivolts on the linear axis. On
the log axis, be sure concentration
numbers within each decade are
increasing with increasing
concentration

incorrect sign

be sure to note sign of millivolt
number correctly

incorrect standards

prepare fresh standards

wrong units used

apply correct conversion factor:
1.0X10-

M = 23.0 ppm as Na

sample pH too acidic

adjust pH with ISA

Drift (reading changing
in one direction)

samples and standards at
different temperature

allow solutions to come to room
temperature before measurement

incorrect reference filling
solution

use recommended filling solution

electrode exposed to
interference

soak overnight in electrode storage
solution

pH too acidic

adjust pH with ISA

ISA not used

use recommended ISA

Low Slope or No Slope

standards contaminated or
incorrectly made

prepare fresh standards

standard used as ISA

use ISA

pH too acidic

adjust pH with ISA

electrode exposed to
interference

soak overnight in electrode storage
solution

air bubble on membrane

remove bubble by redipping probe

Noisy or Unstable
Readings (reading
changing randomly)

defective meter

check meter with shorting strap

ISA not used

use recommended ISA

meter or stirrer not grounded

ground meter or stirrer

defective electrode

replace electrode

electrode exposed to
interference

soak overnight in electrode storage
solution