Martini Instruments Mi 105 User Manual

USER MANUAL
MI 105
Portable
pH/Temperature Meter

GENERAL OPERATION

• The meter is supplied com-
plete with a 9V battery.
Remove the battery com-
partment cover on the
back of the meter and in-
stall the battery while pay-
ing attention to its polarity.
• Connect the MA914BR/1
probe to the meter.
• Turn the instrument on by
pressing the ON/OFF key.
At start-up, the LCD
shows the percentage of
the remaining battery life
for a few seconds, and
then the current measure-
ment.
• Always remove the electrode protective cap
before taking any measurement. If the elec-
trode has been left dry, soak the tip (bottom
2.5 cm) in M10000 rinse solution for a few
minutes.
• Immerse the tip (2.5 cm) of the probe into
the sample and stir gently.
• Read the pH value when the clock symbol
stops blinking.
• The temperature reading can be displayed
in °C or °F unit; to select the desired scale,
press and hold the "ON/OFF" key until "TEMP"
and the current temperature unit are dis-
played on the secondary LCD. Use the "SET"
button to select the unit and then press the
"ON/OFF" key a couple of times to return to
normal mode.
• To activate the HOLD function, keep pressed
the "HOLD" key. The measured value will
be frozen on the display and the "HOLD"
message appear on the secondary LCD.
• After measurements, switch the meter off
by pressing the "ON/OFF" key. The "OFF"
message appears on the LCD; release the
button.
Notes:
• Before taking any measurement, make sure
that the meter has been calibrated (the "CAL"
tag is displayed on the left lower corner of
the LCD).
• Always replace the electrode protective cap
after use with a few drops of storage
solution.

CALIBRATION PROCEDURE

It is recommended to recalibrate the meter at
least once every three weeks.
A) Preparation, Buffer solutions:
1. pH 7.01 / 6.86 (MA9007 / MA9006)
2. pH 4.01 (MA9004) for acidic calibration
(pH < 7) or pH 10.01 / 9.18 (MA9010 /
MA9009) for alkaline range (pH > 7).
Use two beakers for each buffer solution: one
beaker for rinsing the probe, the other for
calibration. In this way the cross contamination
between solutions is minimized.
B) Procedure:
• Select the calibration buffer set: press and
hold the "ON/OFF" key until the LCD shows
"TEMP". Press again this key and the "BUFF"
message will appear; then select the de-
sired buffer set with the "SET" key: "7.01
pH BUFF" (for standard solutions: pH 4.01,
7.01, 10.01) or "6.86 pH BUFF" (for NIST
solutions: pH 4.01, 6.86, 9.18). Press the
"ON/OFF" key again to exit.
• Remove the protective cap, then immerse
the probe in the first buffer (pH 7.01 or
6.86).
• Press and hold the "ON/OFF" key until "CAL"
is displayed on the lower LCD.
• Release the button and the
message "7.01 pH USE" (or
"6.86 pH USE" for NIST
buffer set) will be displayed.
• The meter automatically recognizes the buffer
value: if a valid buffer is detected, then its
value is displayed on the LCD
together with the "REC" mes-
sage, and the first calibra-
tion point is accepted.
• The meter will then require
the second buffer by show-
ing the "pH 4.01 USE" mes-
sage. Immerse the probe in
the second buffer solution
(pH 4.01 or 10.01 or 9.18). If a valid buffer
is recognized, the meter completes the cali-
bration procedure, shows the "OK 2" mes-
sage for a few seconds, then returns to
the normal mode.