Hach IntelliCAL ISENH3181 Series User manual

DOC022.53.80107
ISENH3181
05/2021, Edition 6
User Manual

Table of Contents
Section 1 Product overview................................................................................. 3
Section 2 Specifications ...................................................................................... 3
Section 3 Safety information............................................................................... 4
3.1 Intended use ....................................................................................................... 4
3.2 Use of hazard information..................................................................................... 4
3.3 Precautionary labels............................................................................................. 5
3.4 Product hazards.................................................................................................... 5
Section 4 Preparation for use.............................................................................. 5
Section 5 Calibration............................................................................................... 6
5.1 Calibration notes ................................................................................................. 6
5.2 Calibration procedure........................................................................................... 7
Section 6 Sample measurement....................................................................... 8
6.1 Sample measurement notes ............................................................................... 8
6.2 Sample measurement procedure......................................................................... 8
6.3 Interferences ....................................................................................................... 9
Section 7 Verify the calibration.......................................................................... 9
7.1 Verification procedure......................................................................................... 10
Section 8 Maintenance......................................................................................... 10
8.1 Storage............................................................................................................... 10
Section 9 Troubleshooting ............................................................................... 12
9.1 Slope check........................................................................................................ 13
9.2 Standard additions check................................................................................... 13
Section 10 Consumables..................................................................................... 14
10.1 Accessories...................................................................................................... 15
1

Table of Contents
2

Section 1 Product overview
The Intellical ISENH318 series probes are digital, combination electrodes that measure the ammonia
concentration in wastewater, drinking water and general water samples. The probes have a built-in
temperature sensor, a refillable membrane module and a double-junction reference. The Ammonia
Ionic Strength Adjuster (ISA) increases the solution pH to >11, where ammonium and ammonia are
measured as NH3. A 59-mL bottle of electrode filling solution is supplied with the probe. Refer to
Figure 1.
Figure 1 Probe overview
1 Probe soaker bottle with storage solution 4 Probe body
2 Membrane module protector cap (3x) 5 Electrolyte filling solution
3 Membrane module (3x) 6 Glass electrode and temperature sensor
Section 2 Specifications
Specifications are subject to change without notice.
Specifications Details
Probe type Digital combination gas-sensing ammonia ion selective electrode (ISE)
probe with a refillable outer body, double-junction reference and built-
in temperature sensor
Measurement range 0.01 mg/L (5x10–7 M) to 14,000 mg/L (1 M) as NH3–N
Accuracy ±0.02 mV or 0.05%, whichever is greater
Sample pH range > pH 11 with Ammonia ISA
Reference type Ag/AgCl
Reference junction Double junction (porous PTFE annular ring)
Slope 57 mV/decade (90 to 110% in linear range at 25 °C (77 °F) per
Nernstian theoretical value)
Linear region 0.5 mg/L to 14,000 mg/L as NH3–N
Temperature accuracy ±0.3 °C (±0.54 °F)
Temperature sensor type 30 kΩ NTC thermistor
English 3

Specifications Details
Operating temperature 5 to 50 °C (41 to 122 °F)
Storage temperature 5 to 35 °C (41 to 95 °F)
Minimum sample volume 15 mL
Minimum immersion depth 25.4 mm (1 in.)
Body material (standard) Epoxy
Membrane Replaceable Hach ISENH3181 Ammonia membrane module
Electrolyte filling solution 0.1 M NH4Cl (membrane module)
Reference electrolyte Non-refillable gel reference element
Storage solution Short-term and mid-term storage: 1000 mg/L NH3—N standard
solution
Long-term storage: Hach pH Electrode Storage Solution
Cable connection M12 digital output and connector
Dimensions Diameter: 12 mm (0.47 in.)
Length: 175 mm (6.9 in.) total; 103 mm (4.1 in.) below head
Cable length: ISENH318101: 1 m (3.3 ft); ISENH318103: 3 m (9.8 ft)
Warranty 1 year on the probe. This warranty covers manufacturing defects, but
not improper use or wear.
Certifications CE, FCC/ISED
Section 3 Safety information
3.1 Intended use
The Intellical probes are intended for use by individuals who measure water quality parameters in the
laboratory. The Intellical probes do not treat or alter water.
3.2 Use of hazard information
D A N G E R
Indicates a potentially or imminently hazardous situation which, if not avoided, will result in death or
serious injury.
WARNING
Indicates a potentially or imminently hazardous situation which, if not avoided, could result in death
or serious injury.
CAUTION
Indicates a potentially hazardous situation that may result in minor or moderate injury.
N O T I C E
Indicates a situation which, if not avoided, may cause damage to the instrument. Information that
requires special emphasis.
4 English

3.3 Precautionary labels
Read all labels and tags attached to the instrument. Personal injury or damage to the instrument
could occur if not observed. A symbol on the instrument is referenced in the manual with a
precautionary statement.
Electrical equipment marked with this symbol may not be disposed of in European
domestic or public disposal systems. Return old or end-of-life equipment to the
manufacturer for disposal at no charge to the user.
3.4 Product hazards
CAUTION
Chemical exposure hazard. Obey laboratory safety procedures and wear all of the
personal protective equipment appropriate to the chemicals that are handled. Refer to
the current safety data sheets (MSDS/SDS) for safety protocols.
CAUTION
Chemical exposure hazard. Dispose of chemicals and wastes in accordance with local,
regional and national regulations.
Section 4 Preparation for use
Install a membrane module that contains ammonia electrode filling solution before use.
1. Fill and install the membrane module on the probe. Do not tighten too much. Refer to the
illustrated steps in Figure 2.
Note: Add 12 drops (0.5 mL) of the ammonia electrode filling solution to the membrane module.
2. Condition the probe before use. To condition the probe, soak the probe in a 1000 mg/L NH3—N
standard solution for 30 to 60 minutes. Do not add the ISA to the standard solution.
3. Make sure that the meter has the correct date and time settings. The service-life time stamp in
the probe comes from the date and time settings in the meter.
Note: Some meters automatically open the date and time settings when the meter starts for the first time, or
after battery replacement.
4. Connect the probe to the meter.
English 5

Figure 2 Install the membrane module
Section 5 Calibration
The procedure that follows is applicable to meters that can connect to Intellical ISE probes. Refer to
the applicable meter documentation for meter operation and probe-specific settings.
5.1 Calibration notes
Read the notes that follow before calibration.
• Make sure to install the ammonia membrane module with ammonia electrode filling solution on the
probe.
• Measure the standard solutions from lowest to highest concentration for best results.
• For best results, reset the filling solution after calibration. To reset the filling solution, put the probe
(with installed membrane) in a 1000 mg/L NH3—N standard solution without ISA for 30 seconds to
1 minute.
• Keep all of the solutions (standard solutions and samples) at the same temperature (± 2 °C
(± 3.6 °F)) for best results.
• Stir the standards and samples at a slow and constant rate to prevent the formation of a vortex.
• Use the default calibration options or change the options in the probe settings menu.
• Use the single display mode for calibration when more than one probe is connected to the meter (if
applicable).
• Calibrate the probes and verify the calibration regularly for best results. Use the meter to set
calibration reminders.
• The calibration data is stored in the probe. When a calibrated probe is connected to a different
meter with the same calibration options, a new calibration is not necessary.
• Air bubbles below the sensor when in solution can cause a slow response or error in the
calibration. Make sure to remove air bubbles during calibration.
6 English

5.2 Calibration procedure
1. Go to the
calibrate menu.
Select the probe, if
applicable. The
display shows the
standard solutions to
use for calibration.
2. Add 25 mL of
each standard
solution to different
beakers.
3. Add one
Ammonia Ionic
Strength Adjustor
(ISA) Powder Pillow
to each 25 mL of
standard solution.
Note: As an alternative,
add 0.5 mL of Ammonia
ISA Solution.
4. Add a stir bar to
the first standard
solution. Put the
standard solution on
an electromagnetic
stirrer. Stir at a
moderate rate.
5. Rinse the probe
with deionized water.
Dry the probe with a
lint-free cloth.
6. Put the probe in
the standard solution
with the sensor fully
submerged. Do not
put the probe on the
bottom or sides of
the beaker.
7. Shake the probe
from side to side to
remove air bubbles.
8. Stir for 30 to
60 seconds, then
read the ammonia
concentration of the
standard solution.
9. Do steps 3
through 8 to read the
value of the
remaining standard
solutions.
10. Save the
calibration.
English 7

Section 6 Sample measurement
The procedure that follows is applicable to meters that can connect to Intellical ISE probes. Refer to
the applicable meter documentation for meter operation and probe-specific settings.
6.1 Sample measurement notes
Read the notes that follow before sample measurements.
• Make sure to install the ammonia membrane module with ammonia electrode filling solution on the
probe.
• Rinse the probe with deionized water and dry with a lint-free cloth between measurements to
prevent contamination.
• To measure samples of low concentration after measurements of high concentration, reset the
filling solution for best results. To reset the filling solution, put the probe (with installed membrane)
in a 1000 mg/L NH3—N standard solution without ISA for 30 seconds to 1 minute.
• If the stabilization time is long, try a different stir rate and make sure to condition the probe.
• Keep all of the solutions (standard solutions and samples) at the same temperature (± 2 °C
(± 3.6 °F)) for best results.
• If complete traceability is necessary, enter a sample ID and operator ID before measurement.
Refer to the meter manual for instructions.
• Stir the standards and samples at a slow and constant rate to prevent the formation of a vortex.
• The meter automatically saves the measurement data when the user manually reads each data
point and when the meter is set to read at regular intervals. The user must manually save each
data point when the meter is set to read continuously.
• Air bubbles below the sensor can cause a slow response or error in the measurement. Make sure
to remove air bubbles before and during measurements.
6.2 Sample measurement procedure
1. Pour 25 mL of
fresh sample into a
50‑mL beaker.
2. Add one
Ammonia Ionic
Strength Adjustor
(ISA) Powder Pillow.
Note: As an alternative,
add 0.5 mL of Ammonia
ISA Solution.
3. Add a stir bar.
Put the beaker on an
electromagnetic
stirrer. Stir at a
moderate rate.
4. Rinse the probe
with deionized water.
Dry the probe with a
lint-free cloth.
8 English

5. Put the probe in
the sample with the
sensor fully in the
sample. Do not put
the probe on the
bottom or sides of
the beaker.
6. Shake the probe
from side to side to
refresh the reference
junction and remove
air bubbles.
7. Stir for 30 to
60 seconds, then
read the ammonia
concentration of the
sample. The display
shows the value
when the reading is
stable.
6.3 Interferences
The sensing element will measure some other ions that are known to interfere with the method. The
probe response to other ions usually increases the mV potential and causes a positive error. The
response to other ions can be semi-quantitatively calculated through the Nikolsky equation, an
extended Nernst equation:
E = Eº + (RT/(zF))ln[aNa + KNax × ax]
Where
• ax = the activity of the interfering ion
• KNax = the selectivity coefficient for the interfering ion relative to the primary ion
The primary interferences for ammonia ion-selective electrodes are volatile amines. Most other
gases will change to ionic species at the high pH of the test and will not interfere directly. The
concentration of ions will change the solubility of ammonia. Thus, standard solutions should have
about the same concentration of ions and dissolved species as the samples.
Ammonia forms complexes with a number of metal ions: mercury, silver, copper, gold, nickel, cobalt,
cadmium and zinc. The ammonia ISA contains a high concentration of hydroxide ion and adjusts the
pH to >11, where most metals form complexes with hydroxide or precipitate. Mercury will form a
complex with ammonia when the hydroxide concentration is 0.1 M and the ammonia concentration is
below 10–3 M. Mercury will not interfere if the mercury in the sample is preferentially bound to a
different species such as iodide, which forms a soluble mercury complex at all pH levels.
Section 7 Verify the calibration
Measure the value of a fresh standard solution at regular intervals to make sure the result is
accurate. The meter compares the expected standard solution value to the measured value and
accepts or rejects the measurement. For the best results, reset the filling solution before verification.
To reset the filling solution, put the probe with the installed membrane module in a 1000 mg/L NH3—
N standard solution without ISA for 30 seconds to 1 minute. The user can change the standard
solution and acceptance criteria for verification in the probe-specific settings.
Note: Password protection may prevent access to the acceptance criteria.
English 9

7.1 Verification procedure
1. Go to the
verification menu.
The display shows
the standard solution
to use for
verification.
Note: Menu name for
HQd meters: Run check
standard.
2. Pour 25 mL of the
standard solution
into a 50‑mL beaker.
3. Add one
Ammonia Ionic
Strength Adjustor
(ISA) Powder Pillow.
Note: As an alternative,
add 0.5 mL of Ammonia
ISA Solution.
4. Add a stir bar.
Put the beaker on an
electromagnetic
stirrer. Stir at a
moderate rate.
5. Rinse the probe
with deionized water.
Dry the probe with a
lint-free cloth.
6. Put the probe in
the standard solution
with the sensor fully
in the solution. Do
not put the probe on
the bottom or sides
of the beaker.
7. Shake the probe
from side to side to
remove air bubbles.
8. Stir for 30 to
60 seconds, then
read the value of the
standard solution.
The meter accepts
or rejects the result.
Section 8 Maintenance
Regular maintenance is necessary for the best accuracy, stabilization time and life of the probe.
Make sure to rinse the probe with deionized water between measurements. Keep the probe in the
recommended storage solution when not in use.
For dirty applications such as wastewater, where the samples contain substances (e.g., surfactants,
oils, and fats) that clog or damage the membrane, use the air gap assembly. Refer to Consumables
on page 14. The air gap assembly keeps the membrane module above the sample and significantly
extends the life of the membrane module. Make sure to use the air gap assembly for calibrations,
measurements and verifications.
8.1 Storage
N O T I C E
Probes can become permanently damaged if kept in a storage solution that is not specified by the
manufacturer. Use only the specified storage solution.
10 English

Follow the applicable storage procedure:
•Short-term and mid-term (maximum one week) storage—Put the ammonia probe with the
installed membrane module in a 1000 mg/L NH3—N standard solution without Ionic Strength
Adjustor (ISA). Do not let the membrane dry out. A soaker bottle is not necessary. Put a cover on
the storage beaker and probe body to prevent solution evaporation.
•Long-term (more than one week) storage—Remove the membrane module and soak the probe
in pH Electrode Storage Solution. Refer to Figure 3.
Note: After long-term storage, soak the probe (with the installed membrane module) in a 1000 mg/L NH3—N
standard solution without Ionic Strength Adjustor (ISA) for 30 to 60 minutes for the best stabilization speed.
Figure 3 Long-term storage
English 11

Section 9 Troubleshooting
Refer to Table 1 for general troubleshooting information. To check the accuracy of sample
measurements, refer to Standard additions check on page 13. To check the probe performance,
refer to Slope check on page 13.
Table 1 Troubleshooting information
Problem Possible cause Solution
Decreased probe
performance causes slow
stabilization and prevents
accurate calibrations or
measurements.
The membrane module is
dirty or clogged.
Replace the membrane module and
filling solution, then condition the
probe. Refer to Preparation for use
on page 5. To extend the life of the
membrane module, use the air gap
assembly for calibrations,
measurements and verifications.
The filling solution is low or
is contaminated.
Replace or reset the filling solution.
To reset the filling solution, put the
probe (with the installed membrane)
in a 1000 mg/L NH3—N standard
solution without ISA for 30 seconds to
1 minute.
The probe is not
conditioned sufficiently after
membrane replacement.
Soak the probe (with the installed
membrane module) in a 1000 mg/L
NH3—N standard solution without ISA
for 30 to 60 minutes.
Sample properties cause
slow stabilization or
inaccurate measurements.
Increase the sample
temperature or adjust the
temperature of different
samples to be the same
(within 2 °C (3.6 °F)).
Increase the sample temperature or
adjust the temperature of different
samples to be the same (within 2 °C
(3.6 °F)).
The sample contains
substances (e.g.,
surfactants, oils, and fats)
that clog or damage the
membrane.
Use the air gap assembly for
calibrations, measurements and
verifications.
The sample pH with ISA is
less than pH 11.
Make sure that the sample pH after
the ISA is added is higher than pH 11.
Make sure to add one ISA pillow per
25 mL of sample.
12 English

Table 1 Troubleshooting information (continued)
Problem Possible cause Solution
Procedure problem causes
slow stabilization and
prevents accurate
calibrations or
measurements.
Air bubbles are around or
below the probe tip.
Carefully tap or shake the probe to
remove air bubbles.
The ISA was not added. Add one ISA powder pillow to each
25 mL of sample and standard
solution.
The stir speed is too slow or
too fast.
Try a different stir speed.
Magnetic stirrers can
become warm and increase
the solution temperature.
Put a piece of insulating material
between the stirrer and beaker.
An incorrect standard
solution was used or the
standard solution has
contamination.
Use the specified standard solution of
good quality.
Too much ammonia gas
goes into the air after the
ISA is added.
Measure the sample or standard
solutions immediately after the ISA is
added to prevent the loss of ammonia
gas. Put a cover on the beaker with a
hole for the probe to decrease the
loss of ammonia.
9.1 Slope check
Use the mV value of two standard solutions to make sure the probe gives the correct slope.
1. Prepare two standard solutions that are ten times apart in concentration (e.g., 10 mg/L and
100 mg/L NH3—N). Select standard solutions with a concentration above and below the typical
sample concentration. Use a minimum concentration of 0.5 mg/L.
2. Use the measurement procedure to add the ISA and measure the mV value of each standard
solution.
3. Calculate the difference in the mV value of the two standard solutions to find the slope. If the
probe is in good condition, the slope will be 57 mV (within the ± slope limits of the method) at
25 °C (77 °F).
9.2 Standard additions check
To make sure that the sample measurement is accurate, add a small volume of a standard solution
to the sample and calculate the percent recovery. The sample with the known volume of standard
solution is known as a spiked sample.
1. Use the measurement procedure to measure the concentration of a 25-mL sample.
2. Use a pipet to add the applicable volume of standard solution to the sample. Refer to Table 2.
Table 2 Standard solution volumes and concentrations
Measured sample
concentration
Volume of standard to
add
Concentration of standard solution
1 to 2 mg/L 0.5 mL 100 mg/L NH3—N
3 to 6 mg/L 1.0 mL 100 mg/L NH3—N
7 to 15 mg/L 0.3 mL 1000 mg/L NH3—N
English 13

Table 2 Standard solution volumes and concentrations (continued)
Measured sample
concentration
Volume of standard to
add
Concentration of standard solution
15 to 30 mg/L 0.5 mL 1000 mg/L NH3—N
30 to 60 mg/L 1.0 mL 1000 mg/L NH3—N
3. Measure the concentration of the spiked sample.
4. Calculate the expected (theoretical) concentration of the spiked sample:
CE = (CS x VS/VT) + (CSS x VSS/VT)
Where:
• CE = expected (theoretical) concentration of the spiked sample
• CS = concentration of the sample (mg/L) before the standard solution was added
• CSS = concentration of the standard solution (mg/L)
• VS = sample volume (mL) before the standard solution was added
• VSS = volume of the standard solution (mL)
• VT = total volume (standard solution volume (mL) + sample volume)
5. Calculate the percent recovery of the standard addition. A percent recovery of 100 (±5)% is an
indication that the sample measurements are accurate.
Percent recovery = CM/CE x 100
Where:
• CM = measured concentration of the sample after the addition of the standard solution
• CE = expected (theoretical) concentration of the sample after the addition of the standard
solution
Section 10 Consumables
Note: Product and Article numbers may vary for some selling regions. Contact the appropriate distributor or refer to
the company website for contact information.
Description Quantity Item no.
Ammonia Ionic Strength Adjustor (ISA) Powder Pillows 100/pkg 4447169
Ammonia Ionic Strength Adjustor (ISA) Solution 500 mL 2824349
Ammonia electrode filling solution, 0.1 M NH4Cl 50 mL 4447226
Ammonia standard solution, 1 mg/L as NH3–N 500 mL 189149
Ammonia standard solution, 10 mg/L as NH3–N 500 mL 15349
Ammonia standard solution, 100 mg/L as NH3–N 500 mL 2406549
Ammonia standard solution, 1000 mg/L as NH3–N 1 L 2354153
Hach pH electrode storage solution 500 mL 2756549
Membrane modules for ISENH3181 probes 3/pkg 5812711
Air gap assembly for ammonia ISE 1 5025300
Wash bottle, polyethylene, 500 mL 1 62011
Disposable wipes, 11 x 22 cm 280/pkg 2097000
Beaker, 30 mL, plastic, colorless 80/pkg SM5010
14 English

Section 10 Consumables (continued)
Description Quantity Item no.
Beaker, 100 mL, polypropylene 1 108042
Probe stand for standard Intellical probes 1 8508850
10.1 Accessories
Description Quantity Item no.
Beaker, polypropylene, 50 mL, low form 1 108041
Disposable wipes, 11 x 22 cm 280/pkg 2097000
Wash bottle, polyethylene, 500 mL 1 62011
Probe stand for standard Intellical probes 1 8508850
English 15

16 English

*DOC022.53.80107*
HACH COMPANY World Headquarters
P.O. Box 389, Loveland, CO 80539-0389 U.S.A.
Tel. [phone]
[phone] (U.S.A. only)
Fax [phone]
[email protected]
www.hach.com
HACH LANGE GMBH
Willstätterstraße 11
D-40549 Düsseldorf, Germany
Tel. [phone]
Fax [phone]
[email protected]
www.de.hach.com
HACH LANGE Sàrl
6, route de Compois
1222 Vésenaz
SWITZERLAND
Tel. [phone]
Fax [phone]
© Hach Company/Hach Lange GmbH, 2010-2011, 2013, 2021.
All rights reserved.