Sartorius PB-11 User manual

98648-012-08
Operation Manual
Sartorius Basic Meter PB-11

3
Contents
4General View
6Warning and Safety Information
7Installing and Maintaining lectrodes
9Standardizing for pH Measurement
13 Using Setup
15 Standardizing for Millivolt Measurement
18 Understanding pH Theory
19 Temperature Compensation
20 Measuring pH
21 Troubleshooting
23 Meter Specifications
24 Accessories
25 CDeclaration of Conformity

4
General View
1Setup button:
Press to clear buffers,
revie electrode
calibration or select ne
autorecognized buffers
2Mode button:
Press to toggle bet een
pH and mV mode
3Standardize button:
Press to enter each buffer
4Enter button:
Press to select menu
item options
5Measuring icon
6Temperature
7Mode
8Result
9Prompts
10 Buffer icons
11 Icon: standardization
(calibration of the meter)
in process
12 Stability icon
13 Standardizing icon
14 Standardization result
Front Vie
Display
1
2
3
4
1.68 4.01 6.86 9.18 12.46 S1 S2 S3
32
1%/¡C
Auto
Man
Set
Clear
OK
Error
1234567810101213
Sal
TDS
%DO
mg/L
S/cm cm ion rel mV pH
m
µK
M
°C
S
13
12
11
10
14
5
6
7
8
9
1
2
3

5
1Po er cable connector
2Reference electrode
connector (used ith
separate reference
electrodes)
3BNC electrode connector
4Temperature compensation
probe connector
5AC adapter
Rear Vie
Connecting to a Po er Source
1
2
3
4
1
5

6
Warning and
Safety Information
For safety and operating reasons, only authorized
service technicians may open the Basic Meter PB-11
housing. Therefore, only authorized technicians may
repair or perform maintenance on this pH meter.
Any tampering ith the pH meter or negligent or
intentional damage to this equipment ill void any
arranty claims against the manufacturer.
If liquid gets into the pH meter, unplug it from AC
po er (mains supply) and have an authorized service
technician check the pH meter.
If you do not plan to use this pH meter for a relatively
long period, please disconnect it from AC po er.
For safety reasons, use this equipment only for the
application described in this operation manual.
Make sure that the buffers used for standardizing
have exactly the same values that are stored.

7
Installing and
Maintaining lectrodes
1. Remove the protective end cover from the electrode.
2. Before first use of your electrode, or henever
the electrode is dry, soak overnight in a standard
solution or KCI solution.
3. Remove the shorting cap on the pH meter connector.
Install the electrode by plugging the BNC and ATC
connectors into the jacks on the rear panel.

8
4. Option: Install an ion selective electrode by removing
the BNC shorting cap and plugging the BNC connector
(t ist-lock) into the BNC jack. If a combination
electrode is not available, plug the separate reference
electrode into the ref pin.
5. Clean the electrode bet een each measurement ith
distilled ater or deionized ater, or part of the next
solution to be measured.
6. Store glass pH electrodes in KCI solution or electrode
filling solution. Make sure the liquid level of the
internal filling solution is al ays a fe centimeters
higher than that of the measurement solution.
Reference
Electrode
ISE

9
Standardizing for
pH Measurement
Because electrodes vary in their response, you
must standardize (calibrate) your pH meter and
electrode to compensate for electrode variation.
The more frequently you standardize, the more
accurate your measurements. Standardize daily,
or more often, for accurate results.
This pH meter allo s automatic standardization
using up to three buffers. Press the Standardize
button again to delete all the standardization data
stored up to that point. The pH meter performs
automatic temperature compensation.
1. Immerse electrode in a buffer solution. Stir gently.
Allo the electrode to reach a stable value.
2. Press the Mode button until your digital display
indicates pH mode. This button toggles bet een
pH and mV modes.

10
3. Clear existing buffers hen doing a ne 2- or
3-point standardization. Use the Setup button.
Also use the Setup button to select the individual
sets of buffers. (See page 13.)
4. Press Standardize. The meter recognizes the buffer
and flashes a buffer icon. When the signal is stable,
the buffer is entered. By pressing NT R you can
also enter the current buffer directly.
5. The meter displays the slope of the electrode as
100.0%. On entering a second or third buffer,
the meter performs a diagnostic check on the
electrode and displays the slope. (See step 7 ff.)
[Standardize]

11
6. To enter a second buffer, place the electrode in
the second buffer solution, stir, allo time for the
electrode to stabilize, and press Standardize again.
The meter recognizes the buffer and displays the
first and second buffer values.
7. Next, the meter performs a diagnostic test of
the electrode. The display indicates either Good
Electrode (“OK”) or Electrode Error (“Error”).
The meter also displays the slope of the electrode.
8. rror indicates that your electrode or the buffer
is not orking properly, or a rong set of buffers
has been selected. The electrode response must be
bet een 90 and 105% slope. (See Troubleshooting,
on page 21.) Press nter to clear the Error, then
try re-entering the buffer as described in step 6.
9. To set a third standard, place the electrode in the
third buffer solution, stir, allo to stabilize, and
press Standardize. The results ill be the same
as in steps 6 and 7, except the display ill sho
three buffer values.
[Standardize]
[Standardize]

12
10. After entering three buffers, the Standardizing
icon goes out and the Measuring icon appears
on the display to indicate that the meter returns
to Measuring operation.
!Note:
The meter continually adjusts for temperature.
Therefore, buffers may vary slightly from the
nominal values because of temperature.
11. Standardize your pH meter using at least t o
buffers ith pH values bracketing the expected pH
of your samples. Stirring ith a magnetic stir bar
provides faster electrode response.

13
Using Setup
The Setup button lets you clear all the standardiza-
tion data that you have entered, revie calibration
information, or select the buffer set that you ant.
You can escape the setup mode at any time by
pressing pH/mV.
1. Press Setup once to clear all buffers you have
entered. If you are sure you ant to clear the
buffers, press nter. The meter clears all buffers
and returns to Measuring.
2. Press Setup again to sho electrode performance,
slope and the first and second calibration points.
The t o buffer values ill also be displayed.
3. Pressing Setup again sho s the electrode slope
bet een the second and third buffers (if three
buffers have been entered) and sho s the second
and third buffer icons.
[Setup]
[ nter]
2+[Setup]

14
4. Press Setup again to display a Set Buffers icon
and to display the first buffer set icons.
5. Press nter to select the set of buffers sho n on
the display or Press Setup again to toggle bet een
the existing sets of buffers.
6. Press Enter to select the displayed buffer set that
contains the buffer you ant to use. Press Setup
again, or press the Mode button at any time to
return to Measuring.
!Note:
You may select buffers from different sets.
[Setup] or
[ nter]
[Setup]

15
Standardizing for
Millivolt Measurement
(Relative Millivolt)
You ill normally use millivolt measurements for
determining ion concentration and for measuring
redox potential (also called ORP, oxidation reduction
potential).
You ill use an ion selective electrode (ISE),
combined ith a reference electrode, to measure ion
concentration. The ISE senses the ion concentration
and responds ith a millivolt potential. The millivolt
readings are then used to determine ion concen-
trations (on the basis of a previously entered
calibration curve).
You ill normally use a redox/ORP electrode to
measure redox potential (ORP). ORP measurements
indicate the oxidizing or reducing capability of a
solution. You can use ORP values to monitor or
control solutions requiring a set amount of oxidants
or reductants.
1. Immerse electrode in a standard solution.

16
2. Press Mode until your digital display indicates
mV mode.
3. Press Standardize to enter an mV standard and
read relative mV.
4. When the signal becomes stable, or hen you
press nter, the current absolute mV value (offset)
becomes zero relative millivolts.
[Mode]
[Standardize]

17
5. To clear an mV offset and return to absolute
millivolt mode, press Setup. The meter displays
a flashing Clear icon, and sho s the current
relative millivolt offset.
6. To clear the previous mV offset, press nter.
You then return to absolute mV mode.
[Setup]
[ nter]

18
Understanding pH Theory
Defining pH
The measurement of pH plays an important
role in identifying and controlling acidity
and alkalinity levels for industry and
research. pH is a measure of the acidity
or alkalinity of a solution and can be
represented by this equation:
pH = -log [H+]
ith [H+] representing the concentration
of hydrogen ions in the solution. pH is
sometimes referred to as the po er of the
hydrogen ion in a solution.
By using a pH meter, you can determine
exact pH levels of solutions. For example,
rather than say that lemon juice is quite
acidic, you can say that lemon juice has
a pH of 2.4. An exact pH value can be
used to control or measure acidity levels
for manufacturing processes or for basic
research.
pH values generally range from 0 to14,
ith a pH of 7 being the neutral point,
or the value of pure ater. pH values
greater than 7 represent increasing
alkalinity, hereas pH values belo 7
represent increasing acidity (Figure 1).
pH
0Strong Acid
1
2Lemon Juice
3
4Tomato Juice
5Coffee
6
Neutra 7Pure Water
8Baking Soda
9
(sodium hydrogen carbonate)
10
11
12 Ammonia
13
14 Strong Base
more acidicmore basic
Figure 1.
pH scale sho ing
the relative acidity
or basicity of some
common substances.

19
Temperature
Compensation
!Note: Automatic temperature compensation
only functions properly if a temperature probe
is connected.
Temperature compensation influences the results
in t o different ays:
1. pH values of the buffers change as a function
of temperature.
Each buffer varies as a function of the tempera-
ture of the respective solution. Typically, these
values are indicated on the buffer label. The
values detailed in the table belo apply to most
technical buffers.
If standardization is performed in the pH mode,
the pH value is adapted to the nominal value of
the current temperature.
For example, if the buffer has a nominal pH of
7.00 at a temperature of 25°C, the meter ill
standardize the buffer to 7.02 instead of 7.00 at
a temperature of 20°C.
2. Electrode slope changes as a function of
temperature.
Theoretically, the change of voltage per pH unit
is approx. 59.16 mV at 25°C. Ho ever, this mV
per pH unit changes as a function of temperature.
The meter compensates for these changes by
taking into account the temperature dependency
of the Nernst factor hen calculating pH values.
Standard buffers:
pH 4.00 pH 7.00 pH 10.00
0°C 4.005 7.13 10.34
5°C 4.003 7.10 10.26
10°C 4.001 7.07 10.19
15°C 4.002 7.05 10.12
20°C 4.003 7.02 10.06
25°C 4.008 7.00 10.00
30°C 4.010 6.99 9.94
35°C 4.020 6.98 9.90
40°C 4.030 6.97 9.85
50°C 4.061 6.97 9.78

20
Measuring pH
To measure pH ith a conven-
tional glass pH electrode, the
meter uses a pH-sensing glass
bulb that is sensitive to hydrogen
ions. The potential developed at
the glass membrane is directly
related to the pH of the solution.
The glass electrode is paired
ith a reference electrode
hich completes the electrical
measuring circuit and provides
a stable reference point. These
t o electrodes are joined to
create a combination electrode.
The combination glass electrode
is connected to the pH meter
hich reads the voltage, converts
it to pH units, and displays the
result.
Reference
Electrode
Porous
Junction
(Diaphragm)
pH Sensor
Temperature sensor
ith automatic temperature
compensation (ATC)