PASCO PASPORT PS-2230 User manual

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Instruction Manual
012-14325A
Advanced Water Quality Sensor
PS-2230
Included Equipment Part Number
Advanced Water Quality Sensor PS-2230
Stainless Steel Temperature Probe PS-2153
Conductivity Electrode (10x) PS-2571
Optical Dissolved Oxygen Probe 003-14185
pH Electrode PS-2573
Required Equipment
PASPORT Interface and Software See PASCO catalog or www.pasco.com
Optional Equipment Part Number
Optical Dissolved Oxygen Probe Metal Guard PS-2588
Skin/surface Temperature Probe PS-2131
Conductivity Electrode (1x) 699-06620
Various Ion-selective Electrodes (ISE) See PASCO catalog or www.pasco.com
Oxidation Reduction Potential (ORP) Electrode CI-6716
Replacement Item Part Number
Optical Dissolved Oxygen Probe Sensor Cap PS-2587

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Advanced Water Quality Sensor Introduction
2012-14325A
Introduction
The PS-2230 Advanced Water Quality Sensor combines four sensors in a single unit:
• Temperature
• Conductivity
• pH (or Ion-Selective Electrode, or Oxygen Reduction Potential, optional)
• Dissolved Oxygen (DO2)
Note: The Optical Dissolved Oxygen Probe also measures barometric pressure and solution tem-
perature.
When connected to a PASPORT interface, the multi-sensor collects data at up to 2
samples per second from each component sensor. One component sensor can be used
at a time or any combination can be used simultaneously. If you have a PASPORT
interface that supports multiple sensors, or if you have more than one interface con-
nected to your computer, the Advanced Water Quality Sensor can be used in combina-
tion with other PASPORT sensors.
Note: No electrical interference will occur between two or more probes connected to a single
Advanced Water Quality Sensor.
Sensor, Interface, and Software Setup
Connect the multi-sensor to your PASPORT interface as pictured (right). Con-
nect any or all of the included probes to the multi-sensor. (You can leave any
probe disconnected if you do not plan to use it.) If you will be using an
ion-selective electrode or oxygen reduction potential electrode, connect it to
the pH/ISE/ORP port.
Follow the instructions below to set up the sensor with PASCO Capstone,
SPARKvue, SPARK SLS, or the Xplorer GLX (standalone).
For detailed information about each of the multi-sensor’s component sensors,
see the following pages.
Note: Only the tips and bodies of the probes should be immersed in liquid. Keep the con-
nectors and body of the multi-sensor dry. The probe cables are immersible.
Capstone Setup
Connect the PASPORT interface using a Capstone supported interface. Build
one or more displays for data. Click ‘Record’ to start data collection and ‘Stop’
to stop data collection.
Note that the sensor will collect data for probes that are not connected. These data are
listed in the Data Summary and are displayed if selected on one or more displays. The
default sampling rate and other parameters are defined with Hardware Setup in the
Tool Palette. If needed, calibration is performed with the Calibration wizard in the
Tool Palette. For more instructions on using Capstone, refer to the Capstone Online
Help or User’s Guide.
pH or ISE
or ORP
Conductivity
DO2Temperature
PASPORT
Interface

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Model No. PS-2230 Temperature
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012-14325A
SPARKvue and SPARK SLS Setup
Connect the PASPORT interface directly to a SPARK SLS or to a computer using a
SPARKvue supported interface. Build one or more displays for data. Press to
start data collection and to stop data collection.
The default sampling rate is defined with Sampling Options. Calibration is performed
with Experiment Tools > Calibrate Sensor. For more instructions on using the
SPARKvue/SPARK SLS, refer to the SPARKvue/SPARK SLS Online Help or User’s
Guide.
Xplorer GLX Setup
If you are using an Xplorer GLX in standalone mode, press to start data collec-
tion.
Note that the sensor may collect data for probes that are not connected. Hide or ignore
these measurements. To hide measurements that you do not need, open the Sensors
screen (from the Home screen, press ). In the Sensors screen you can also
change the sampling rate and open the calibration dialog box. For more instructions
on using the Xplorer GLX, refer to the GLX User’s Guide.
Temperature
Use this component of the multi-sensor to measure the temperature of a fluid or
object. The measurement can be displayed in units of °C, °F, or K. You can use the
included stainless steel probe or a different probe, such as the Fast-response Probe
(PS-2135) or Skin/Surface Probe (PS-2131). PASCO physics apparatus containing an
embedded 10 kthermistor can also be connected to the multi-sensor. The multi-sen-
sor automatically detects the presence of a temperature probe, and it will only collect
temperature data if a probe is connected.
Measuring Temperature
To measure temperature, connect the probe and start data collection. Immerse the tip
of the probe in a fluid or place it in contact with an object. The included stainless steel
probe can be used in both dry conditions and in liquids, such as water and other mild
chemicals and solutions.
Tip: For better chemical resistance, use a Teflon®cover (CI-6549).
Temperature Calibration
The temperature measurement can be calibrated; however, for most applications cali-
bration is not necessary. Use a two-point calibration with two standards of known
temperature. Refer the SPARKvue/SPARK SLS, Capstone, or Xplorer GLX Online
Help or User’s Guide for calibration instructions.
Conductivity
The conductivity component sensor measures the electrolytic conductivity of aqueous
solutions. It determines the conductivity by applying an alternating voltage to the
electrode cell at the end of the probe and measuring the resulting current. You can use
the included 10x electrode or an optional1x electrode (not included). In the software
F4
platinized
platinum
conductors
glass rod
Conductivity Electrode

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Advanced Water Quality Sensor Conductivity
4012-14325A
or on the interface select the Conductivity (10x) or Conductivity (1x) measurement,
depending on which electrode you are using.
Note: The 10x probe can be used to measure conductivity up to 100000  S/cm. The 1x probe
has one tenth of the range (up to 10000
 S/cm) but ten times better resolution.
Measuring Conductivity
Before using the conductivity electrode, soak the end in distilled water for 5 to 10
minutes. Connect the electrode to the multi-sensor and start data collection. Immerse
the end of the electrode in the solution to be measured and wait for the reading to sta-
bilize. Rinse the electrode with deionized water before measuring a different solution.
The conductivity sensor has three ranges, which you select using the three buttons on
the multi-sensor. To select a range, push one of the buttons: for 0 S/cm to 1k (1000)
S/cm, for or 1k S/cm to 10k S/cm, or for 10k S/cm to 100k S/cm. Lights on the
buttons indicate which range is selected. To determine which range is appropriate,
look at the data (on a Graph display, for instance) while it is being collected; if the
measurement appears to be “railed” at the top of the selected range (1k S/cm or 10k
S/cm), select the next higher range. You can push a button to change the range with-
out stopping data collection.
Note: The ranges specified above are for a 10x probe. Divide each range by 10 if you are using a
1x probe.
The conductivity electrode is sensitive to very low concentrations of dissolved solids,
so you will probably never measure a sample with a conductivity of zero. A reading
of 25 S/cm for “pure” water is typical. True pure water is difficult to obtain and
store. The table (right) lists typical conductivity values for common aqueous solutions
at 25 °C.
As a rule of thumb, to estimate total dissolved solids (TDS) in parts per million
(ppm), divide the conductivity in S/cm by 2:
Conductivity Calibration
The conductivity measurement can be calibrated; however, for most applications cali-
bration is not necessary. Use a one-point calibration with a standard solution of
known conductivity. For instructions on preparing a standard solution, see Appendix
A. Refer to the SPARKvue/SPARK SLS, Capstone, or Xplorer GLX User’s Guide or
Online Help for calibration instructions.
Conductivity Electrode Maintenance And Storage
To ensure accurate and reproducible results, the electrode must be clean. Substances
on the electrode may contaminate the solution being tested and change the conductiv-
ity. To clean the electrode, dip the end into a detergent solution or dilute nitric acid
(1%) and stir for three minutes, then rinse with deionized water.
For storage, dry the electrode and return it to its box. Before use, soak the electrode in
distilled water for at least 5 minutes.
Solution Conduc-
tivity
(S/cm)
Ultra-
pure
Water
0.05 to
0.75
Drinking
Water
50 to
1500
Ocean
Water
~53000
TDS (ppm) Conductivity S/cm
2
------------------------------------------------------
=

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Model No. PS-2230 pH/ISE/ORP
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pH/ISE/ORP
The pH/ISE/ORP input of the multi-sensor is a specialized voltage sensor. Its BNC
connector accepts the included pH electrode, as well as ISE and ORP electrodes (not
included). The sensor measures the voltage produced by any of these electrodes.
When used with a pH probe, the sensor also computes the pH based on the measured
voltage.
Connect the pH electrode (or other electrode) to the pH/ISE/ORP port and start data
collection. On your computer or interface, display the ISE Voltage measurement (this
measurement is valid for pH and ORP electrodes as well as ISE) or the pH measure-
ment for the calculated pH (assuming that the pH electrode is connected).
Measuring pH
The pH electrode produces a voltage proportional to the pH of the solution that it is
immersed in. This voltage is measured by the multi-sensor, which computes pH.
Unscrew and remove the storage bottle from the electrode (be careful not to spill the
storage solution). Push the O-ring and bottle cap up the electrode handle. Rinse the
electrode tip with distilled water. If you see bubbles in the electrode bulb, gently
shake the electrode downward (similar to shaking down a thermometer). Start data
collection. Place the tip of the electrode in the solution to be measured and wait for
the reading on your computer or interface to stabilize. Rinse the electrode with dis-
tilled water before measuring another solution.
pH Calibration
The pH measurement can be calibrated; however, for most applications calibration is
not necessary. Perform a two-point calibration with two buffer solutions of known
pH. Refer to the SPARKvue/SPARK SLS, Capstone, or Xplorer GLX User’s Guide or
Online Help for calibration instructions.
pH Electrode Maintenance and Storage
Cleaning
If the pH electrode becomes contaminated, use one of these methods to clean and
restore it. After any of these procedures, soak the electrode in a pH 7 buffer solution
for 30 minutes.
•General Contamination: Soak the electrode in 0.1 molar hydrochloric acid
(HCl) for 15 minutes.
•Protein Deposits: Soak the electrode in a solution of 1% pepsin in 0.1 molar
HCl.
•Inorganic Deposits: Rinse the electrode with 0.1 molar ethylene diamine
tetra-acetic acid (EDTA) tetrasodium solution.
•Oil and Grease Film: Wash the electrode carefully in a mild detergent or a sol-
vent known to be effective for the particular film.
•Unknown Contamination: Soak the electrode alternately in 12 molar sodium
hydroxide (NaOH) and 1 molar HCl. Leave it in each solution for one minute.
Rinse completely between soakings. End with HCl. (The NaOH etches the glass
and the HCl reestablishes hydrogen ions on the surface.)

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Advanced Water Quality Sensor Dissolved Oxygen
6012-14325A
If these steps fail to improve the response of the electrode, replace it.
Storage
Store the pH electrode in the included electrode storage bottle with one of the follow-
ing solutions. (Never store the electrode in distilled water.)
•Short-term (up to one week): pH 4 buffer solution or tap water.
•Long-term (over one week): 4 molar KCl solution (included with the electrode).
Dissolved Oxygen
The Optical Dissolved Oxygen Probe is designed to measure the concentration and
the saturation percentage of dissolved oxygen molecules (O2) in aqueous solutions.
The Optical Dissolved Oxygen Probe has several advantages when compared to a gal-
vanic (electrochemical) dissolved oxygen sensor. The advantages include:
• no warm up time
• no calibration required
• no filling solution or electrode polishing
• no flow dependency
The sensing element of the Optical Dissolved Oxygen Probe is called the Sensor Cap.
The sensing element has two layers, The outer layer is a paint that acts as an oxygen
permeable diffusion layer which allows oxygen molecules to pass though while pro-
tecting the dye layer. The sensing layer is an immobilized polystyrene dye layer that
luminesces when excited with light of the correct wavelength. The probe measures
dissolved oxygen by emitting a blue light of the proper wavelength that causes the
dye in the sensing layer to luminesce (glow) a red color. Oxygen dissolved in the sam-
ple being tested continually passes through the diffusion layer to the dye layer, affect-
ing the luminescence lifetime and intensity of the dye. The sensor’s photo-diode
measures the lifetime of the luminescence as it is affected by the oxygen and com-
pares the reading to a reference.
Factors that Affect Dissolved Oxygen Measurement
Factors that affect dissolved oxygen measurement include temperature, barometric
pressure, and salinity.
Temperature: The rate of diffusion of oxygen through the Sensor Cap changes with
temperature (approximately 1.5% per degree celsius). The Optical Dissolved Oxygen
Sensor Cap
Nose-piece,
Optical Dissolved
Oxygen Probe
Diffusion Layer
Sensing Layer
Photo-diode and Light
Emitting Diodes (LED)
NOTE: Do not remove the
Sensor Cap except to replace it.

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Model No. PS-2230 Dissolved Oxygen
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Probe has a built-in thermistor, and the temperature changes are compensated for by
proprietary algorithms that use readings from the thermistor.
Barometric Pressure: The partial pressure of oxygen in a sample of air or water is not
affected by barometric pressure, but dissolved oxygen concentration in milligrams per
liter is affected. The Optical Dissolved Oxygen Probe has a built-in barometer, and
the reading from that device is used to determine the oxygen pressure during calibra-
tion.
Salinity: As the salinity of water increases, its ability to dissolve oxygen decreases.
(Note: The user will be able to enter a value for the “salinity constant” in the data
acquisition software.) For precise measurement of salinity, the PS-2195
Salinity Sensor is recommended (see the web site at www.pasco.com).
*Salinity is a unit-less measurement determined from conductivity and temperature
readings according to the Practical Salinity Scale. Historically, salinity values deter-
mined with the Practical Salinity Scale were given the designation “ppt” because
these values were very close to those determine by the previously used method where
the mass of dissolved salts in a given mass of water (parts per thousand) were
reported.
Dissolved Oxygen Calibration
The Optical Dissolved Oxygen Probe is calibrated at the factory and does not need to
be re-calibrated under most circumstances. However, if the Sensor Cap is replaced
with a new Sensor Cap (PS-2587), then the Sensor Cap Calibration Code Coefficients
(included with the new Sensor Cap) will need to be entered into the sensor using the
PASCO data acquisition software. The sensor will then need to be re-calibrated. (See
Appendix B.)
For a one-point calibration, you will need one “known standard” with 100% dissolved
oxygen saturation.
For a two-point calibration, you will need two “known standards”; one with 100%
dissolved oxygen saturation, and one with 0% dissolved oxygen saturation.
Refer to the SPARKvue/SPARK SLS, Capstone, or Xplorer GLX User’s Guide or
Online Help for calibration instructions, or go to the PASCO Web site at
www.pasco.com and enter “Optical Dissolved Oxygen Sensor” or “PS-2196” in the
Search window. Download the instruction manual PDF file under “User Resources”.
Known Standards
One method for a known standard with 100% dissolved oxygen saturation is to use
water-saturated air. Moisten the sponge inside the end of the Probe Cover (included
with the probe) with water, and then put the probe into the Probe Cover for about fif-
teen minutes.
CAUTION: Do not push the Probe Cover on too tight or it might cause a pressure
increase.
Water Type Average Salinity
Fresh water <0.5 ppt*
Brackish water 0.5 to 30 ppt
Sea water 33 to 47 ppt
Saline water 30 to 50 ppt
Brine >50 ppt

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Advanced Water Quality Sensor Dissolved Oxygen
8012-14325A
A second method for a known standard with 100% dissolved oxygen saturation is to
use air-saturated water. Connect an air-stone to an air pump, and put the air-stone into
water. Allow the air-stone and air pump to run for 10 minutes to make sure that the
water is completely saturated.
For a known standard with 0% dissolved oxygen saturation, dissolve enough sodium
sulfite in 150 milliliters of distilled water such that a small amount of sodium sulfite
remains undissolved in the bottom of the beaker.
Probe Care and Maintenance
The sensing layer in the Optical Dissolved Oxygen Probe’s Sensor Cap degrades over
time due to bleaching caused by exposure to light, so the Sensor Cap must be replaced
periodically. It should also be replaced if it is cracked, scratched, or damaged. The
Sensor Cap is warranted for one year and may last much longer. The working life of a
Sensor Cap may be extended by keeping it clean and properly stored between uses.
The replacement for the Optical Dissolved Oxygen Probe Sensor Cap is model num-
ber PS-2587 (see www.pasco.com for more information).
NOTE: Do not remove the Sensor Cap except to replace it with a new
cap.
To clean the Sensor Cap, rinse it with clean water and dry it with a lint free cloth. If
necessary, use a mild detergent. Do not use alcohols or other organic solvents that
may deteriorate the sensing layer. When changing the Sensor Cap, rinse the clear
front surface of the nose-piece of the probe with clean water and then dry the surface
with a lint free cloth or lens tissue.
Optical Dissolved Oxygen Probe Attacking Liquids
Alcohols will remove the paint layer of the Sensor Cap.
The following will remove the paint and dye layers of the Sensor Cap and will attack
the probe housing as well:
Storage
The Optical Dissolved Oxygen Probe should not be allowed to dry out. For storage,
keep the Sensor Cap installed on the probe. Moisten the sponge that is in the end of
the Probe Cover, and place the probe in the cover so that the Sensor Cap is next to the
moist sponge.
Do not store the probe directly in water since that would encourage algae growth on
the probe.
Toluene Benzene Carbon tetrachloride Chloroform
Methylene chloride Acetone Methyl ethyl ketone Organic solvents

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Model No. PS-2230 SpecificationsReference Solutions for Conductivity Calibration
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Appendix A: SpecificationsReference
General
Included Sensors Temperature, Conductivity, pH, Optical Dissolved Oxygen
Max. Sampling Rate 20 samples per second (for each component sensor)
Default Sampling
Rate
2 samples per second
Temperature
Range 35 °C to 135 °C
Accuracy 0.5 °C
Resolution 0.01 °C or better
Sensing Element 10 kthermistor located in probe tip
Conductivity
Range three user-selectable ranges:
0 to 1000 S/cm, 0 to 10000 S/cm, 0 to 100000 S/cm with included 10x probe
0 to 100 S/cm, 0 to 1000 S/cm, 0 to 10000 S/cm with optional 1x probe
Accuracy ±10% of full scale without calibration
Resolution better than 0.05% of full scale
pH/ISE/ORP probe voltage
Electrode Connector standard BNC
Input Resistance 1012 
Voltage Range 2000 mV to 2000 mV
Voltage Resolution 0.1 mV
pH Range 0 to 14
pH Resolution 0.001
Optical Dissolved Oxygen Probe
Cable Length 3 meters
Response Time 90% in 35 seconds
Operating Temperature 0 to 50 °C
Operating Pressure 375 to 825 mm Hg
Range 0 to 20 mg per liter or 0 to 300% saturation
Resolution 0.01 °C or better
Accuracy ±0.6 mg per liter or ±3.0% right out of the box
±0.1 mg per liter or ±1.0%, whichever is greater, after calibration
above 200% saturation, ±10%

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Advanced Water Quality SensorOptical Dissolved Oxygen Probe Replacement Cap Cal-
10 012-14325A
Solutions for Conductivity Calibration
Appendix B: Optical Dissolved Oxygen
Probe Replacement Cap Calibration
After a new replacement Sensor Cap (PS-2587) is placed on the Optical Dissolved
Oxygen probe, there are two parts to the sensor calibration process.
1. With the probe connected to the sensor and the sensor connected to the PASCO Inter-
face, use the data acquisition software to enter the Calibration Code coefficients (six
groups of numbers labeled K1 to K5 and KC) for the replacement Sensor Cap into the
sensor.
2. Perform a one-point calibration using a “known standard” such as air-saturated water.
Alternatively, a two-point calibration could be performed using two calibration stan-
dard solutions.
3. Refer to the User’s Guide or Online Help for the PASCO software, or go to the
PASCO web site at www.pasco.com and enter “Optical Dissolved Oxygen Sensor” or
“PS-2196” in the Search window. Download the instruction manual PDF file under
the User Resources tab.
Capstone: Calibration Code Coefficients
The replacement Sensor Cap comes with a Calibration Code Label (see the example).
Reference
Solution
Approximation
Normality of
Solution
Method of Preparation Temperature
(°C)
Electrical
Conductivity1
(µS/cm)
A 1 74.2480 g of KCI weighed in air per 1 L of
solution at 20 °C
0 65176
18 97838
25 111342
B 0.1 7.4365 g of KCI weighed in air per 1 L of
solution at 20 °C
0 7138
18 11167
25 12856
C 0.01 0.7440 g of KCI weighed in air per 1 L of
solution at 20 °C
0 773.6
18 1220.5
25 1408.6
D 0.001 Dilute 100 mL of solution C to 1 L at 20 °C 0 77.69
18 127.54
25 148.93
1Excluding the conductivity of the water used to prepare the solutions. These tabulated conductivity values are in international
units. When using measuring instruments calibrated in absolute units, multiply the tabular values by 0.999505
Example: Calibration Code Label