Milwaukee MI455 PRO User manual

INSTRUCTION MANUAL
SATISFACTION
GUARANTEED
MI455 PRO
Free & Total Sulphur Dioxide
Mini Titrator for Wine Analysis

All rights are reserved. Reproduction in whole or in part is prohibited without the written
consent of the copyright owner, Milwaukee Instruments Inc., Rocky Mount, NC 27804 USA.
THANK YOU for choosing Milwaukee Instruments!
This instruction manual will provide you the necessary information for correct use
of the meter.

3
TABLE OF CONTENTS
1. FUNCTIONAL DESCRIPTION......................................................................................................................................4
2. GENERAL DESCRIPTION.............................................................................................................................................6
3. PRINCIPLE OF OPERATION........................................................................................................................................8
4. SPECIFICATIONS.............................................................................................................................................................8
5. STARTUP .............................................................................................................................................................................9
6. GUIDE TO DISPLAY CODES......................................................................................................................................10
7. GENERAL TIPS FOR AN ACCURATE MEASUREMENT.................................................................................12
8. PUMP CALIBRATION PROCEDURE......................................................................................................................13
9. FREE SO₂ MEASUREMENT PROCEDURE .........................................................................................................15
10. TOTAL SO₂ MEASUREMENT PROCEDURE ..................................................................................................... 17
11. PUMP TUBE REPLACEMENT..................................................................................................................................19
12. FUSE REPLACEMENT...............................................................................................................................................20
13. ELECTRODE CONDITIONING & MAINTENANCE..........................................................................................21
14. ACCESSORIES..............................................................................................................................................................23
CERTIFICATION..................................................................................................................................................................24
RECOMMENDATION........................................................................................................................................................24
WARRANTY..........................................................................................................................................................................25

4MI455 Mini Titrator for Wine Analysis
1. FUNCTIONAL DESCRIPTION
Display
A. HOURGLASS ICON
B. STIRRER ACTIVE TAGS
C. ERROR MESSAGE
D. MEASURE STATUS
E. CALIBRATION MODE INDICATOR
F. MAIN DISPLAY
G. MEASUREMENT UNIT
H. TIMER MODE INDICATOR
I. SECONDARY DISPLAY
Keypad
MI455 PRO Sulphur Dioxide
Mini Titrator
A. PUMP – to start/stop the pump
B. CAL – to enter pump calibration mode
C. STIR – to start/stop the stirrer while in measurement or purging mode
D. START STOP – to start/stop titration or pump calibration

FUNCTIONAL DESCRIPTION 5
Front Panel
A. TITRANT BOTTLE
B. LIQUID CRYSTAL DISPLAY (LCD)
C. KEYPAD
D. ELECTRODE HOLDER
Rear Panel
E. ORP ELECTRODE
F. PERISTALTIC PUMP TUBE
G. BEAKER
H. PERISTALTIC PUMP
I. BNC ELECTRODE CONNECTOR
J. FUSE
K. POWER CABLE CONNECTOR
L. POWER SWITCH

6MI455 Mini Titrator for Wine Analysis
2. GENERAL DESCRIPTION
The MI455 is a low-cost, easy to use, microprocessor-based automatic titrator. It has a
simple and reliable peristaltic pump that ensure high dosing repeatability. By performing
pump calibration with the provided Milwaukee standards, the instrument accuracy is
assured.
The instrument comes with a pre-programmed analysis method designed for Free and
Total Sulphur Dioxide measurements on wine samples. The instrument has a powerful
and eective built-in algorithm to analyze the shape of the electrode response and to
determine the reaction completion. This algorithm automatizes the analysis, makes all
the necessary calculations and assures a simple and eective interface for the user.
By simply pressing the START STOP button, the instrument will automatically make the
titration up to the equivalence point. The result is immediately displayed in convenient
units, then the instrument is ready for another titration.
Significance of Use
An important reason for adding SO₂ is to avoid oxidation. When there is oxygen around,
SO₂ itself becomes oxidized before phenol compounds in the wine, and so acts as an
oxygen scavenger. Also SO₂ suppresses the activity of enzymes that cause browning and
other problems.
What is really protecting your wine is molecular SO₂. When you add SO₂, depending
of circumstances, some of it immediately becomes bound. The relationship between
the amount of added SO₂ and the amount of SO₂ remaining free is complex. It is clear,
however, that it is largely governed by the total SO₂ content of the wine. The rate of binding
decreases as the free SO₂ concentration increases. The exact relationship between free
and bound (total – free) SO₂ will vary from wine to wine.
Below 30-60 ppm, 33% to 50% of SO₂ addition becomes bounded. What remains is
called “free” and it is divided in two parts. The larger, and relatively ineective free part is
“bisulphite” (HSO3¯). The smaller part of the free is the active molecular SO₂. The amount
of molecular SO₂ in your wine depends both on the level of free SO₂ present as well as
pH. For instance, at pH 3.2, the amount of free SO₂ for 0.8 ppm molecular SO₂ is 22 ppm.
AtpH3.5, you will need 43 ppm free – essentially double.
Free SO₂ concentration (ppm) for 0.8 ppm molecular SO₂:
pH 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9
Free SO₂ 14 18 22 28 35 44 55 69 87 109

GENERAL DESCRIPTION 7
In most situations, 0.8 ppm molecular SO₂ during bulk storage and at bottling will
provide you with adequate protection from oxidation and bacterial action. This includes
prevention of malolactic bacteria as well.
It is important to remember that the amount of free SO₂ in the wine depends on three
things: how much is added, how much was present before the addition and how much of
your addition promptly becomes bound.
The level at which molecular SO₂ can be detected by the human senses is about 2.0ppm.
This is also the level which is needed for maximum protection of your wine. This is
particularly true in the case of sweet, and most notably, botrytised wines.
The Milwaukee MI455 oers the possibility to test free or total SO₂ in all the wines
including the red ones, that are diicult to test with manual methods because the color
changes are hardly seen.
This meter is supplied with:
yReagent set for SO₂ determinations
yTwo 100 mL beakers
yTwo 20 mL beakers
yTubes set with cap
yORP probe
yStir bar
yPower cable
yOne 230 mL bottle of Refill Solution
yOne plastic pipette
yInstruction manual
yWarranty code
Note: Save all packing material until you are sure that the instrument works correctly.
Any defective item must be returned in its original packing.

8MI455 Mini Titrator for Wine Analysis
3. PRINCIPLE OF OPERATION
Determination of sulphur dioxide in wine samples is made by titration of the sulphur
dioxide present in wine with iodate. In this procedure an excess of iodine is added to the
wine sample and it is titrated with iodate.
For precise results it is very important to know the exact sample volume, titrant volume
and concentration.
The peristaltic pump has a good repeatability but the dosing volume depends on many
factors as the diameter of the tube or the tube stretching. To compensate for all this errors,
the pump need to be calibrated. The calibration of the pump is also needed in order to
have high precision of the titrations.
The calibration procedure is in fact the analysis of a known solution. By doing this, the
instrument makes a dierential analysis between the standard and the wine sample. The
pump volumetric debit and the real concentration of the titrant is compensated. Only the
sample volume has to be precisely known.
4. SPECIFICATIONS
Range 0 to 400 ppm SO₂
Resolution 1 ppm
Accuracy 5% of reading
Method Ripper titrimetric method
Principle Equivalence point redox titration
Sample volume 50 mL
ORP Electrode MA924B/1 (included)
Pump debit 0.5 mL/min
Stirring speed 700 rpm
Environment 0 to 50 °C (32 to 122 °F) ; max 95% RH non-condensing
Power supply MI455-01: 115 V/60 Hz; 10 VA
MI455-02: 230 V/50 Hz; 10 VA
Dimensions 208 x 214 x 163 mm (8.2 x 8.4 x 6.4”) (with beaker)
Weight 2200 g (77,6 oz.).

STARTUP 9
Required Reagents
Code Description Quantity/test
Mi555-001 Standard (for Free & Total SO₂) 50 mL
Mi555-002 Titrant (for Free & Total SO₂)
Mi555-003 Alkaline Reagent (for Total SO₂) 5 mL
Mi555-004 Acid Reagent (for Total SO₂) 5 mL
Mi555-005 Acid Reagent (for Free SO₂) 5 mL
Mi555-006 Stabilizer (for Free & Total SO₂) 1 packet
5. STARTUP
yPlace the instrument on a flat table. Do not place the instrument on direct sun light.
yConnect the titrator to mains socket with ground connection and the correct voltage
and frequency. See the label on the instrument rear for this.
yPlace the peristaltic pump tube on the pump. See the Pump Tube Replacement
section for the procedure.
yRemove the reagent bottle cap and place the bottle cap of the tubes set. Place the
reagent bottle in the appropriate place on the titrator top.
yConnect the tubes with the peristaltic pump (inlet tube is connected with the reagent
bottle, outlet tube is connected with the dosing tip).
yTurn the instrument ON using the power switch from the rear panel of the instrument
and wait until it displays dashes.

10 MI455 Mini Titrator for Wine Analysis
6. GUIDE TO DISPLAY CODES
This screen appears for a few seconds each time the
instrument is turned ON.
Main screen display.
Main screen display with stirrer active.
Purging mode message.
Pump Calibration Messages
This screen appears each time the meter enters pump
calibration mode. The meter is ready to start pump
calibration by pressing the START STOP button.
This screen appears while pump calibration is in progress.
Pressing CAL or START STOP button, the minititrator
returns to the main screen.
This screen appears for a few seconds before returning to
the main screen, when pump calibration is done.

GUIDE TO DISPLAY CODES 11
This error message appears when the sample
concentration exceeds 400 ppm.
The used standard solution is wrong.
This error message appears when the input readings (mV)
exceed the input limits (0÷1000mV).
Titration Messages
This screen appears each time a titration is running. When
the START STOP button is pressed the minititrator returns
to the main screen.
The titration result, expressed as concentration of sulphur
dioxide in ppm (mg/L), is displayed at the end of the titration
process. Press the START STOP button to return to the main
screen.
This error message appears when the input reading exceeds
the input limits (0÷1000mV).
This screen appears when the sample concentration
exceeds 400 ppm.

12 MI455 Mini Titrator for Wine Analysis
7. GENERAL TIPS FOR AN ACCURATE MEASUREMENT
The instructions listed below should be carefully followed during testing to ensure best
accuracy.
yPurge the peristaltic pump to have fresh titrant when starting a new analysis or
calibration.
yCalibrate the peristaltic pump before performing an analysis.
yAnalyze the wine immediately after the sample is obtained.

PUMP CALIBRATION PROCEDURE 13
8. PUMP CALIBRATION PROCEDURE
Warning: The calibration of the pump must be performed each time the pump tube,
the reagent bottle or the pH electrode is changed. It is recommended to perform the
pump calibration before each set of measurements.
yUsing a clean pipette, fill the 100 mL beaker up to the 50 mL mark with MI555-001
Standard.
Note: Failure to use clean pipettes will result in erroneus readings.
MI555-001 Standard50 mL
yPlace the stir bar in the beaker and put the beaker in the minititrator top.
yFill the 20 mL beaker up to the 5 mL mark with the MI555-005 Acid Reagent and add
the content to the 100 mL beaker.
MI555-005 Acid Reagent
yPlace the beaker into the beaker holder.
yPlace the probe holder on the top of the beaker and secure by turning clockwise.
yOpen refill cap on the ORP electrode and immerse the electrode approximately 2 cm
(0.8”) into the sample to be tested. Do not touch stir bar with the tip of the electrode.
yEnsure there is titrant in the dosing tip. If not, hold the dosing tip over an empty
container and press PUMP for a few seconds until the titrant is in the dosing tip.

14 MI455 Mini Titrator for Wine Analysis
yAdd the contents of one powder packet of MI555-006 Stabilizer into the beaker.
MI555-006 Stabilizer
yPress CAL button. The meter enters in pump calibration mode.
yPress START STOP in order to start the system calibration.
yAt the end of the calibration, DONE appears for a few seconds and the meter returns
to the measurement mode.

FREE SO₂ MEASUREMENT PROCEDURE 15
9. FREE SO₂ MEASUREMENT PROCEDURE
yUsing a clean pipette, fill the 100 mL beaker up to 50 mL mark with the wine sample.
Note: It is important to be accurate in your measurements of Wine sample. Pipettes
are recommended.
Wine Sample50 mL
yPlace the stir bar in the beaker and put the beaker in the minititrator top.
yFill the 20 mL beaker up to the 5 mL mark with the Mi555-005 Acid Reagent and add
the content to the 100 mL beaker.
MI555-005 Acid Reagent
yPlace the probe holder on the top of the beaker and secure by turning clockwise.
yOpen refill cap on the ORP electrode and immerse the electrode approximately 2 cm
(0.8”) into the sample to be tested. Do not touch stir bar with the tip of the electrode.
yInsert dosing tip into holder. Ensure there is titrant in the dosing tip. If not, hold the
dosing tip over an empty container and press PUMP for a few seconds until the titrant
is in the dosing tip. The tip should be below the pump to ensure gravity flow.
Note: Be aware of any air bubbles in the tube it could eect the results.
yAdd the contents of one powder packet of Mi555-006 Stabilizer into the beaker.
MI555-006 Stabilizer

16 MI455 Mini Titrator for Wine Analysis
yPress START STOP in order to start titration. The display will show “----” during
titration, along with stirrer and pump tags blinking on the LCD.
yAt the end of the titration, the Sulphur Dioxide concentration is displayed in mg/L
(ppm).

TOTAL SO₂ MEASUREMENT PROCEDURE 17
10. TOTAL SO₂ MEASUREMENT PROCEDURE
yFill the 100 mL beaker up to 50 mL mark with the wine sample.
Note: It is important to be accurate in your measurement of wine sample. Pipettes
are recommended.
Wine Sample50 mL
yPlace the stir bar in the beaker and put the beaker in the minititrator top.
yFill the 20 mL beaker up to the 5 mL mark with the Mi555-003 Alkaline Reagent and
add the content to the 100 mL beaker.
MI555-003 Alkaline Reagent
ySwirl the beaker and wait for 15 minutes.
yFill the 20 mL beaker up to the 5 mL mark with the Mi555-004 Acid Reagent and add
the content to the 100 mL beaker.
MI555-004 Acid Reagent
yOpen refill cap on the ORP electrode and immerse the electrode approximately 2 cm
(0.8”) into the sample to be tested. Do not touch stir bar with the tip of the electrode.
yInsert dosing tip into holder. Ensure there is titrant in the dosing tip. If not, hold the
dosing tip over an empty container and press PUMP for a few seconds until the titrant
is in the dosing tip. The tip should be below the pump to ensure gravity flow and
minimize the chance of air bubbles in the tube.

18 MI455 Mini Titrator for Wine Analysis
yAdd the content of one powder packet of Mi555-006 Stabilizer into the beaker.
MI555-006 Stabilizer
yPress START STOP button to start titration. The display will show “----” during titration,
along with stirrer and pump tags blinking on the LCD.
yAt the end of the titration, the Sulphur Dioxide concentration is displayed in mg/L (ppm).

PUMP TUBE REPLACEMENT 19
11. PUMP TUBE REPLACEMENT
To remove the tube of the peristaltic pump follow next steps:
yDetach the old tube system from the reagent bottle.
yGrasp one fixing ring of the peristaltic pump tube.
yPull the tube until it’s taken out from its location.
yRemove the other side of the tube.
To mount the new peristaltic pump tube follow next steps:
yPosition one peristaltic pump fixing ring on its location.
yStretch the tube over the peristaltic pump cylinders.
yFix the second pump fixing ring on its location.
yAttach the tube to the reagent bottle.
Note: Purge the peristaltic pump until drops of reagent appears on the dosing tip by
pressing the PUMP button.

20 MI455 Mini Titrator for Wine Analysis
12. FUSE REPLACEMENT
To change the fuse follow next steps:
yDisconnect the power cord from the rear panel of the instrument.
yPull out the fuse holder located near the power cord connector.
yReplace the fuse with a similar one.
yPush the fuse holder with the fuse in the appropriate place.