Thermo Scientific Orion Star Series User manual

North America
166 Cummings Center
Beverly, MA 01915 USA
Toll Free: 1-800-225-1480
Tel: [phone]
Dom. Fax: [phone]
Int’l Fax: [phone]
Europe
Denmark House, Angel Drove
Ely, Cambridgeshire
England, CB7 4ET
Tel: [phone]
Fax: [phone]
Asia Pacific
Blk 55, Ayer Rajah Crescent
#04-16/24, Singapore 139949
Tel: [phone]
Fax: [phone]
www.thermo.com/water
©2008 Thermo Fisher Scientific Inc. All rights reserved. All trademarks are the property of Thermo Fisher Scientific Inc.
and its subsidiaries. ROSS and the COIL trade dress are trademarks of Thermo Fisher Scientific Inc.
Environmental Instruments
Water Analysis Instruments
1 of 4
Conductivity of
Water USP <645>
Key Words
• Conductivity
• USP <645>
• Deionized Water
• Purified Water
• Water for
Injection
• Conductivity Cell
Star Series
Method Note
M-1700
Introduction
is method describes the technique for measuring the direct conductivity of purified water and water for
injection based on Stage 1 of USP <645> Water Conductivity procedures. e ermo Scientific Orion
stainless steel conductivity probe, Cat. No. 013016MD, with a cell constant of 0.1 cm-1 is used for this
analysis. is method is intended for general field or laboratory use when measuring low conductivity or
pure water samples such as deionized water.
Recommended Equipment Cat. No.
Conductivity Application Kit (includes listed items with a Cat. No.) 1010152
1. 5-Star Plus benchtop pH/ISE/DO/conductivity meter 1119000
2. Star Plus Navigator 21 and 21 CFR Part 11 software 1010017
3. Conductivity probe with flow cell 013016MD
4. ROSS Ultra® combination pH electrode 8102BNUWP
5. Stirrer probe (or magnetic stir plate and bar) 096019
6. Swing arm electrode stand 090043
7. Conductivity resistor calibration kit 1010001
8. 150 mL beakers
Required Solutions Cat. No.
1. 100 μS/cm conductivity standard, 5 x 60 mL bottles 011008
2. pH 4.01 buffer, 475 mL bottle 910104
3. pH 7.00 buffer, 475 mL bottle 910107
4. pH 10.01 buffer, 475 mL bottle 910110
5. pH electrode storage solution, 475 mL bottle 910001
6. ROSS electrode filling solution 810007
7. Deionized water
Note: e stirrer probe, Cat. No. 096019, has been added as optional equipment for Stage 2 if the measured
conductivity does not meet the requirements of Stage 1 of the USP <645> Water Conductivity procedures. A ROSS
Ultra pH electrode and pH 4.01, 7.00 and 10.01 buffers have been included in this kit for Stage 3 if the measured
conductivity does not meet the requirements of Stage 2.
Calibration Standard Preparation
Two 60 mL bottles of the 100 μS/cm conductivity standard are required. One is used for rinsing the
conductivity probe and the other is used for checking the calibration of the conductivity probe. Open the
first bottle of the 100 μS/cm conductivity standard and use it to rinse the probe. A calibration check can
then be performed by inserting the probe directly into the second 100 μS/cm conductivity standard bottle.
Standards may be reused once for rinsing; however, a fresh bottle of 100 μS/cm conductivity standard
should be used each day.

2 of 4
Sample Preparation
1. Using a 150 mL beaker, collect about 100 mL of purified water or water for injection and measure it
immediately (within 5 seconds). Alternately, use the flow cell that is included with the conductivity probe.
2. Repeat step 1 for additional samples.
Results
Five aliquots of deionized water were measured and the obtained conductivity results demonstrated good
repeatability. e temperature value was 22 °C for the above results. From the Physical Tests, <645> Water
Conductivity Stage 1 Table for Temperature and Conductivity Requirements, 1.1 μS/cm is the limit at
20 °C. Better results may be obtained using the flow cell included with the 013016MD conductivity probe if
the measured conductivity is less than 1 μS/cm. If the measured conductivity is higher than the table value,
proceed with Stage 2 as described in the USP <645> Water Conductivity procedures.
Deionized Water Conductivity (µS/cm)
Sample # 1: 0.09
Sample # 2: 0.07
Sample # 3: 0.08
Sample # 4: 0.08
Sample # 5: 0.07
Mean: 0.08
Standard Deviation: 0.01
% CV 10.73
Stage 1 Table for Temperature and Conductivity Requirements – For non-temperature compensated
conductivity measurements only
Temperature Conductivity
Requirement (µS/cm )
Temperature Conductivity
Requirement (µS/cm )
0 0.6 55 2.1
5 0.8 60 2.2
10 0.9 65 2.4
15 1.0 70 2.5
20 1.1 75 2.7
25 1.3 80 2.7
30 1.4 85 2.7
35 1.5 90 2.7
40 1.7 95 2.9
45 1.8 100 3.1
50 1.9
Conductivity of
Water USP <645>

3 of 4
Conductivity Probe Storage
1. For overnight and longer, cell should be stored clean and dry.
2. Storing the probe in water is acceptable between measurements.
Equipment Set Up
Electrode Setup – Conductivity Probe
1. Thoroughly rinse the conductivity probe with deionized water. Gently shake off any excess water.
2. Enter the cell constant value that is printed on the cable of the conductivity probe.
a. In the measurement mode, press the LINE SELECT key until the arrow icon points to the middle line,
press the UP ARROW key until the μS/cm or mS/cm icon is shown and press the CALIBRATE key.
b. The manual calibration screen will display the cell constant on the top line, a conductivity value on the
middle line and “CELL” on the bottom line. To change the cell constant, within 5 seconds press the
DIGIT key until the first digit to be changed is flashing, press the UP/DOWN ARROW key to change
the value of the flashing digit and continue to change the digits until the value matches the cell constant
printed on the cable. Once the value is set, press the DIGIT key until the decimal point is in the
correct location.
c. Press the MEASURE key to save and end the calibration.
Note: In the calibration screen, start changing the cell constant within five seconds or the meter will proceed to
the automatic/direct calibration screen. If this occurs, press and hold the MEASURE key to abort the calibration
and then repeat the calibration.
Meter Setup – 5-Star Plus Benchtop pH/ISE/DO/Conductivity Meter
For initial meter setup, follow the steps in the quick start guide that is included with the meter. e quick start
guide also contains a layout of the meter keypad for reference. e words in all capital letters, such as POWER,
indicate a key on the meter and words in quotations, such as “rES”, indicate a display on the meter screen.
1. Connect the conductivity probe to the meter.
2. Press the POWER key on the meter to turn the meter on.
3. Note that the arrow on the left of the screen indicates the active line. If the middle line is not active, press
the LINE SELECT key to change the selected line to the middle line. Press the UP or DOWN ARROW
key to change the measurement mode of the middle line to conductivity (μS/cm).
4. Press the SETUP key. Press the UP or DOWN ARROW key until “COnd” is displayed on the top line.
5. Press the LINE SELECT key to select the middle line. Press the UP or DOWN ARROW key to select
“tC”, which is for the conductivity temperature compensation type. Press the LINE SELECT key to
select the bottom line. Press the UP or DOWN ARROW key to select “OFF” for “tC”. Press the LINE
SELECT key to accept the setting.
6. Press the LINE SELECT key to select the middle line. Press the UP or DOWN ARROW key to select
“tYPE”, which is for the conductivity cell type. Press the LINE SELECT key to select the bottom line.
Press the UP or DOWN ARROW key to select “Std” for “tYPE”. Press the LINE SELECT key to accept
the setting.
7. Press the LINE SELECT key to select the middle line. Press the UP or DOWN ARROW key to select
“trEF”, which is for the reference temperature used with temperature compensation. Press the LINE
SELECT key to select the bottom line. Press the UP or DOWN ARROW key to select “25” for “trEF”.
Press the LINE SELECT key to accept the setting.
8. Press the MEASURE key to return to the measurement mode.
9. If all steps were followed correctly, the meter display will show “μS/cm” to the right of the middle line.
The meter and probe are now ready for calibration.

North America
166 Cummings Center
Beverly, MA 01915 USA
Toll Free: 1-800-225-1480
Tel: [phone]
Dom. Fax: [phone]
Int’l Fax: [phone]
Europe
Denmark House, Angel Drove
Ely, Cambridgeshire
England, CB7 4ET
Tel: [phone]
Fax: [phone]
Asia Pacific
Blk 55, Ayer Rajah Crescent
#04-16/24, Singapore 139949
Tel: [phone]
Fax: [phone]
www.thermo.com/water
©2008 Thermo Fisher Scientific Inc. All rights reserved. All trademarks are the property of Thermo Fisher Scientific Inc.
and its subsidiaries. ROSS and the COIL trade dress are trademarks of Thermo Fisher Scientific Inc.
Environmental Instruments
Water Analysis Instruments
Calibration Check and Analysis
1. Allow the conductivity standards to reach room temperature for precise measurements, since conductivity measurements are
temperature sensitive and the conductivity temperature compensation is off.
2. Two 60 mL bottles of the 100 μS/cm conductivity standard are required. One is used for rinsing the conductivity probe and the
other is used for checking the calibration of the conductivity probe. Open the first bottle of the 100 μS/cm conductivity standard
and use it to rinse the probe. A calibration check can then be performed by inserting the probe directly into the second 100
μS/cm conductivity standard bottle. Standards may be reused once for rinsing; however, a fresh bottle of 100 μS/cm conductivity
standard should be used for each new calibration.
3. Rinse the probe with the first bottle of standard and place the probe into the second bottle of standard, as stated above.
4. In the measurement mode, press the MEASURE key. The μS/cm icon will flash as the measurement is being made. The μS/cm
icon will become solid and the display value will freeze when a stable reading is achieved
5. Record the measured conductivity value and temperature and compare it to the conductivity values in Table 2. If the results are
within 2% of the expected conductivity value, the calibration check passed. If the results are outside 2%, try the following:
a. Review the Meter Setup section to verify that the parameters are set properly. b. Rinse the conductivity probe and soak it in
deionized water for 5 minutes. Repeat steps 3 through 5. c. Clean the probe with warm water and alkaline detergent for 10 to 30
minutes while stirring and repeat step b. d. Re-enter the cell constant value as described in the Electrode Setup section.
6. Rinse the probe thoroughly with deionized water. Remove excess solution from the probe by gently shaking it.
7. Prepare a sample as described in the Sample Preparation section. The sample must be measured immediately after being collected
and the probe must be immersed in at least 2 inches of sample.
8. Place the probe in a prepared sample with the tip fully immersed in the solution. Press the MEASURE key. The μS/cm icon will
flash as the reading stabilizes. The μS/cm icon will become solid and the value will freeze when a stable reading is achieved.
9. Use the Stage 1 Table to find the temperature value closest to the sample temperature that is not greater than the sample
temperature. The corresponding conductivity value is the conductivity limit for the sample at the measured temperature. If
the measured conductivity value is not greater than the table value, the water meets the requirements of the USP <645> test for
conductivity. If the conductivity is higher than the table value, proceed with the Stage 2 USP <645> Water Conductivity.
10. Repeat steps 6 through 9 for additional samples. When all samples have been measured, rinse probe with deionized water and
store the probe according to the Probe Storage section.
Table 2 – Expected Conductivity Value of the 100 µS/cm Conductivity Standard at Various Temperatures
Temp
(°C)
Cond
(µS/
cm)
Temp
(°C)
Cond
(µS/
cm)
Temp
(°C)
Cond
(µS/
cm)
Temp
(°C)
Cond
(µS/
cm)
Temp
(°C)
Cond
(µS/
cm)
Temp
(°C)
Cond
(µS/
cm)
Temp
(°C)
Cond
(µS/
cm)
18.0 86.4 19.9 90.1 21.8 93.8 23.7 97.5 25.6 101.3 27.4 104.9 29.2 108.6
18.1 86.6 20.0 90.3 21.9 94.0 23.8 97.7 25.7 101.5 27.5 105.1 29.3 108.8
18.2 86.8 20.1 90.5 22.0 94.2 23.9 97.9 25.8 101.7 27.6 105.3 29.4 109.0
18.3 87.0 20.2 90.7 22.1 94.4 24.0 98.1 25.9 101.9 27.7 105.5 29.5 109.2
18.4 87.2 20.3 90.9 22.2 94.6 24.1 98.3 26.0 102.1 27.8 105.7 29.6 109.4
18.5 87.4 20.4 91.0 22.3 94.7 24.2 98.5 26.1 102.3 27.9 105.9 29.7 109.6
18.6 87.6 20.5 91.2 22.4 94.9 24.3 98.7 26.2 102.5 28.0 106.1 29.8 109.8
18.7 87.8 20.6 91.4 22.5 95.1 24.4 98.9 26.3 102.7 28.1 106.3 29.9 110.0
18.8 88.0 20.7 91.6 22.6 95.3 24.5 99.1 26.4 102.9 28.2 106.5 30.0 110.2
18.9 88.2 20.8 91.8 22.7 95.5 24.6 99.3 26.5 103.1 28.3 106.7 30.1 110.4
19.0 88.3 20.9 92.0 22.8 95.7 24.7 99.5 26.6 103.3 28.4 106.9 30.2 110.6
19.1 88.5 21.0 92.2 22.9 95.9 24.8 99.7 26.7 103.5 28.5 107.1 30.3 110.8
19.2 88.7 21.1 92.4 23.0 96.1 24.9 99.9 26.8 103.7 28.6 107.3 30.4 111.0
19.3 88.9 21.2 92.6 23.1 96.3 25.0 100.1 26.9 103.9 28.7 107.5 30.5 111.2
19.4 89.1 21.3 92.8 23.2 96.5 25.1 100.3 27.0 104.1 28.8 107.8 30.6 111.4
19.5 89.3 21.4 93.0 23.3 96.7 25.2 100.5 27.1 104.3 28.9 108.0 30.7 111.6
19.6 89.5 21.5 93.2 23.4 96.9 25.3 100.7 27.2 104.5 29.0 108.2 30.8 111.9
19.7 89.7 21.6 93.4 23.5 97.1 25.4 100.9 27.3 104.7 29.1 108.4 30.9 112.1
19.8 89.9 21.7 93.6 23.6 97.3 25.5 101.1
257478-001 Rev. A 07-08