SULF-50
H2S black tip
MR sensor
Needle sensor
fx-6 UniAmp
Designed for research applications within:
Environmental Sciences
Biomedical Sciences
Biotechnology
Microbiology
Biogeochemistry

H2S Microsensor

Detect H2S in your sample

You can choose the H2S microsensor with a tip size down to 10 µm for high spatial resolution of H2S microprofiles, and with a fast response time of down to <10 seconds, you get a reliable tool for studying H2S production and oxidation. Read more...

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Technical Data
Chemical Interferences
Ordering Information & Sizes
Adaptations
Manuals & Videos
H2S Microsensor

Two types of H2S microsensors

Unisense offers two types of H2S microsensors with different characteristics, SULF and H2S.

Both types are miniaturized amperometric sensors with a sensing anode polarized against an internal reference. Driven by the external partial pressure, H2S from the environment penetrates through the sensor tip membrane into the electrolyte where the H2S is ultimately oxidised by the anode. This generates a current in the pA range which is measured by a high quality picoammeter, such as the UniAmp Multi Channel.

Read more about the our two different types of H2S microsensors below.

H2S in biofilm_700x480

Which H2S sensor should you choose?

The type 1 sensor should be chosen in most environments because of higher signal-to-noise ratio and longer expected lifetime. If hydrogen is present in significant concentrations type 2 should be used.

To calculate total sulfide concentrations, it is also required to measure the pH in the sample.

Type 1: SULF sensor

In the type 1 sensor (SULF), the signal is generated by oxidation of H2S directly on the anode in the tip of the sensor. The type 1 sensor is sensitive to hydrogen and should not be used in environments with high hydrogen concentrations. However, the type 1 sensor is not sensitive to light, and it has a higher signal-to-noise ratio. Additionally, you get a longer warranty and expected lifetime.

Type 2: H2S sensor

The type 2 (H2S) sensor is a customized sensor for environments containing H2. In the type 2 sensor (H2S-xxx), the H2S enters through the membrane in the tip and is converted to HS- ions in the alkaline electrolyte. This is immediately oxidized by ferricyanide, producing sulfur and ferrocyanide. The sensor signal is generated by re-oxidation of ferrocyanide at the anode in the tip of the sensor (see Jeroschewski et al. 1996). The internal guard electrode facilitates a constant ratio of ferri- to ferrocyanide in the electrolyte, thus minimizing the zero current. The ferri-/ferrocyanide complex is light sensitive and the sensors are coated black to minimize light interference.

Type 2 H2S is made against a 10% customization fee compared to the equivalent SULF.

Reference

Jeroschewski, P., C. Steuckart, and M. Kühl. 1996. An amperometric microsensor for the determination of H2S in aquatic environments. Analytical Chemistry 68: 4351–4357.

SULF type I_700x480 H2S type II_700x480
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Type 1: SULF
Type 2: H2S
General
Cables & Connectors
Characteristics
Stirring Sensitivity & Response Time
General
Feature Standard Options Extra price for option selection
Feature
Total length
Standard
150-200 mm
Options
70-350 mm
Extra price for option selection
20-50%
Feature
Diameter 20 mm from tip
Standard
< 2 mm
Options
< 1 mm
Extra price for option selection
10%
Feature
Diameter 50 mm from tip
Standard
8 mm
Options
< 2 mm
Extra price for option selection
20%
Feature
Glass shaft diameter
Standard
8 mm
Feature
Plastic shaft protection diameter*
Standard
11 mm
Options
Can be omitted
Extra price for option selection

*When mounted with in situ mini connectors, the shaft has no protection mounted, but fits directly into the in situ sensor mounts with pressure compensation. In situ sensors have a standard length of 130-160 mm.

Cables & Connectors
Item Standard Options Extra price for option selection
Item
Cable
Standard
Habia
Item
Cable length
Standard
1.5-2 m
Options
0-10 m
Extra price for option selection
Yes, depends on length
Item
Connector
Standard
LEMO
Options
BNC adaptor
Extra price for option selection
Yes, order separately
Item
In situ gold pin connector*
Standard
No
Options
Yes

*When mounted with in situ mini connectors, the shaft has no protection mounted, but fits directly into the in situ sensor mounts with pressure compensation. In situ sensors have a standard length of 130-160 mm.

Characteristics
Attribute Standard Options Extra price for option selection
Attribute
Guaranteed lifetime
Standard
6 months
Attribute
Expected lifetime
Standard
> 1 Year
Attribute
Temperature range
Standard
-2-60°C, tip only
Attribute
Temperature coefficient
Standard
2-3% per °C
Attribute
Range
Standard
About 0-300 µM H2S in water
Options
0-10 mM
Extra price for option selection
20%
Attribute
Linear range
Standard
About 0-300 µM H2S in water | About 0-10 µM for LR (Low Range) sensors | About 0-1 µM for Ultra LR sensors
Options
0-10 mM
Extra price for option selection
20%
Attribute
Detection limit
Standard
0.3 µM | Low Range sensors 10 nM
Options
2-3 nM (only for 200 µm and 500 µm tip sizes)
Extra price for option selection
20%
Attribute
Internal reference
Standard
Yes
Attribute
Waterproof
Standard
Yes
Attribute
Pressure tolerant sensing tip
Standard
Yes
Attribute
Spatial resolution
Standard
Equals outside tip diameter
Attribute
Signal drift
Standard
25% per month
Stirring Sensitivity & Response Time
Item Stirring sensitivity Response time (90%) Extra price
Item
SULF
Stirring sensitivity
<2%
Response time (90%)
<10 s | <20 s on Low Range sensors | <60 s on optional 2-3 nM sensors
General
Cables & Connectors
Characteristics
Stirring Sensitivity & Response Time
General
Feature Standard Options Extra price for option selection
Feature
Total length
Standard
150-200 mm
Options
70-350 mm
Extra price for option selection
20-50%
Feature
Diameter 20 mm from tip
Standard
< 2 mm
Options
< 1 mm
Extra price for option selection
10%
Feature
Diameter 50 mm from tip
Standard
8 mm
Options
< 2 mm
Extra price for option selection
20%
Feature
Glass shaft diameter
Standard
8 mm
Feature
Plastic shaft protection diameter*
Standard
11 mm
Options
Can be omitted
Extra price for option selection

*When mounted with in situ mini connectors, the shaft has no protection mounted, but fits directly into the in situ sensor mounts with pressure compensation. In situ sensors have a standard length of 130-160 mm.

Cables & Connectors
Item Standard Options Extra price for option selection
Item
Cable
Standard
Habia
Item
Cable length
Standard
1.5-2 m
Options
0-10 m
Extra price for option selection
Yes, depends on length
Item
Connector
Standard
LEMO
Options
BNC adaptor
Extra price for option selection
Yes, order separately
Item
In situ gold pin connector*
Standard
No
Options
Yes

*When mounted with in situ mini connectors, the shaft has no protection mounted, but fits directly into the in situ sensor mounts with pressure compensation. In situ sensors have a standard length of 130-160 mm.

Characteristics
Attribute Standard Options Extra price for option selection
Attribute
Guaranteed lifetime
Standard
3 months
Attribute
Expected lifetime
Standard
> 6 months
Attribute
Temperature range
Standard
-2-60°C
Attribute
Range
Standard
About 0-1 mM H2S in water
Options
0-50 mM
Extra price for option selection
20%
Attribute
Linear range
Standard
About 0-300 µM H2S in water | About 0-100 µM for LR (Low Range) sensors
Options
0-20 mM
Extra price for option selection
20%
Attribute
Detection limit
Standard
0.3 µM | 30 nM for H2S-50LR | 20 nM for H2S-100/500/NP LR
Attribute
Internal reference
Standard
Yes
Attribute
Internal guard
Standard
Yes
Attribute
Waterproof
Standard
Yes
Attribute
Spatial resolution
Standard
Equals outside tip diameter
Attribute
Signal drift
Standard
50% per month
Stirring Sensitivity & Response Time
Item Stirring sensitivity Response time (90%) Extra price
Item
H2S
Stirring sensitivity
<2%
Response time (90%)
<10 s | H2S-500 <20 s
Extra price
15%
Type 1: SULF
Type 2: H2S
Chemical Interferences
Chemical Interferences
Name Formula Interference for gases in gas phase (%) Interference for gases dissolved in water (%)
Name
Methane
Formula
CH4
Interference for gases in gas phase (%)
0*
Interference for gases dissolved in water (%)
0**
Name
Carbon dioxide
Formula
CO2
Interference for gases in gas phase (%)
0
Interference for gases dissolved in water (%)
0
Name
Nitrogen
Formula
N2
Interference for gases in gas phase (%)
0
Interference for gases dissolved in water (%)
0
Name
Oxygen
Formula
O2
Interference for gases in gas phase (%)
0
Interference for gases dissolved in water (%)
0
Name
Air
Formula
O2, N2, Ar
Interference for gases in gas phase (%)
0
Interference for gases dissolved in water (%)
0
Name
Nitrous oxide
Formula
N2O
Interference for gases in gas phase (%)
0
Interference for gases dissolved in water (%)
0
Name
Ammonia
Formula
NH3
Interference for gases in gas phase (%)
0
Interference for gases dissolved in water (%)
0
Name
Hydrogen
Formula
H2
Interference for gases in gas phase (%)
0.8
Interference for gases dissolved in water (%)
96
Name
Carbon monoxide
Formula
CO
Interference for gases in gas phase (%)
0.6
Interference for gases dissolved in water (%)
77
Name
Dimethyl sulfide
Formula
(CH3)2S
Interference for gases in gas phase (%)
18
Interference for gases dissolved in water (%)
18
Name
Methyl mercaptan
Formula
CH3SH
Interference for gases in gas phase (%)
174
Interference for gases dissolved in water (%)
44
Name
Ethyl mercaptan
Formula
C2H6S
Interference for gases in gas phase (%)
13
Interference for gases dissolved in water (%)
14
Name
Sulfur dioxide
Formula
SO2
Interference for gases in gas phase (%)
40
Interference for gases dissolved in water (%)
1

*Given as signal for the interfering species in % of H₂S signal at equal partial pressures

**Given as signal for the interfering species in % of H₂S signal at equal molar concentrations

Chemical Interferences
Chemical Interferences
Name Formula Interference for gases in gas phase (%) Interference for gases dissolved in water (%)
Name
Methane
Formula
CH4
Interference for gases in gas phase (%)
0*
Interference for gases dissolved in water (%)
0**
Name
Carbon dioxide
Formula
CO2
Interference for gases in gas phase (%)
0
Interference for gases dissolved in water (%)
0
Name
Nitrogen
Formula
N2
Interference for gases in gas phase (%)
0
Interference for gases dissolved in water (%)
0
Name
Oxygen
Formula
O2
Interference for gases in gas phase (%)
0
Interference for gases dissolved in water (%)
0
Name
Air
Formula
O2, N2, Ar
Interference for gases in gas phase (%)
0
Interference for gases dissolved in water (%)
0
Name
Nitrous oxide
Formula
N2O
Interference for gases in gas phase (%)
0
Interference for gases dissolved in water (%)
0
Name
Ammonia
Formula
NH3
Interference for gases in gas phase (%)
0
Interference for gases dissolved in water (%)
0
Name
Hydrogen
Formula
H2
Interference for gases in gas phase (%)
0.03
Interference for gases dissolved in water (%)
4
Name
Carbon monoxide
Formula
CO
Interference for gases in gas phase (%)
4
Interference for gases dissolved in water (%)
487
Name
Dimethyl sulfide
Formula
(CH3)2S
Interference for gases in gas phase (%)
3
Interference for gases dissolved in water (%)
3
Name
Methyl mercaptan
Formula
CH3SH
Interference for gases in gas phase (%)
117
Interference for gases dissolved in water (%)
30
Name
Ethyl mercaptan
Formula
C2H6S
Interference for gases in gas phase (%)
8
Interference for gases dissolved in water (%)
9
Name
Sulfur dioxide
Formula
SO2
Interference for gases in gas phase (%)
34
Interference for gases dissolved in water (%)
1

*Given as signal for the interfering species in % of H₂S signal at equal partial pressures

**Given as signal for the interfering species in % of H₂S signal at equal molar concentrations

Type 1: SULF
Type 2: H2S
Ordering information & Sizes
Ordering information & Sizes
Type 1: SULF Size and description Options Extra price for option selection
Type 1: SULF
SULF-10
Size and description
8-12 µm - glass sensor
Options
3-5 µm
Extra price for option selection
20%
Type 1: SULF
SULF-25
Size and description
20-30 µm - glass sensor
Type 1: SULF
SULF-50
Size and description
40-60 µm - glass sensor
Type 1: SULF
SULF-100
Size and description
90-110 µm - glass sensor
Type 1: SULF
SULF-200
Size and description
175-225 µm - glass sensor
Type 1: SULF
SULF-500
Size and description
400-600 µm - glass sensor
Type 1: SULF
SULF-Eddy
Size and description
40-60 µm - for Eddy Correlation System
Type 1: SULF
SULF-50LR
Size and description
40-60 µm - low range
Type 1: SULF
SULF-100LR
Size and description
90-110 µm - low range
Type 1: SULF
SULF-500LR
Size and description
400-600 µm - low range
Type 1: SULF
SULF-MR
Size and description
400-600 µm - in guide
Options
100-400, 600-800 µm
Extra price for option selection
20%
Type 1: SULF
SULF-N
Size and description
1.1 x 40 mm - needle sensor
Type 1: SULF
SULF-NP
Size and description
1.6 x 40 mm - needle sensor for piercing
Type 1: SULF
SULF-NPLR
Size and description
1.6 x 40 mm - needle sensor for piercing - low range
Type 1: SULF
SULF-ST-1/4
Size and description
1/4'' steel tube
Type 1: SULF
SULF-SL-1/4
Size and description
FT-cell 1/4'' Swagelok Tee
Type 1: SULF
SULF-SL-1/8
Size and description
FT-cell 1/8'' Swagelok Tee
Type 1: SULF
SULF-PEEK-1/8
Size and description
FT-cell 1/8'' PEEK Tee
Type 1: SULF
SULF-PEEK-1/16
Size and description
FT-cell 1/16'' PEEK Tee
Type 1: SULF
SULF-FT-GLASS-6
Size and description
Glass FT-cell 6mm outer diameter
Type 1: SULF
SULF-FT-GLASS-8
Size and description
Glass FT-cell 8mm outer diameter
Ordering information & Sizes
Ordering information & Sizes
Type 2: H2S Size and description Options Extra price for option selection
Type 2: H2S
H2S-10
Size and description
8-12 µm - glass sensor
Options
3-5 µm
Extra price for option selection
20%
Type 2: H2S
H2S-25
Size and description
20-30 µm - glass sensor
Type 2: H2S
H2S-50
Size and description
40-60 µm - glass sensor
Type 2: H2S
H2S-100
Size and description
90-110 µm - glass sensor
Type 2: H2S
H2S-200
Size and description
175-225 µm - glass sensor
Type 2: H2S
H2S-500
Size and description
400-600 µm - glass sensor
Type 2: H2S
H2S-Eddy
Size and description
40-60 µm - for Eddy Correlation System
Type 2: H2S
H2S-50LR
Size and description
40-60 µm - low range
Type 2: H2S
H2S-100LR
Size and description
90-110 µm - low range
Type 2: H2S
H2S-500LR
Size and description
400-600 µm - low range
Type 2: H2S
H2S-MR
Size and description
400-600 µm - in guide
Options
100-400, 600-800 µm
Extra price for option selection
20%
Type 2: H2S
H2S-N
Size and description
1.1 x 40 mm - needle sensor
Type 2: H2S
H2S-NP
Size and description
1.6 x 40 mm - needle sensor for piercing
Type 2: H2S
H2S-NPLR
Size and description
1.6 x 40 mm - needle sensor for piercing - low range
Type 2: H2S
H2S-ST-1/4
Size and description
1/4'' steel tube
Type 2: H2S
H2S-SL-1/4
Size and description
FT-cell 1/4'' Swagelok Tee
Type 2: H2S
H2S-SL-1/8
Size and description
FT-cell 1/8'' Swagelok Tee
Type 2: H2S
H2S-PEEK-1/8
Size and description
FT-cell 1/8'' PEEK Tee
Type 2: H2S
H2S-PEEK-1/16
Size and description
FT-cell 1/16'' PEEK Tee
Type 2: H2S
H2S-FT-GLASS-6
Size and description
Glass FT-cell 6mm outer diameter
Type 2: H2S
H2S-FT-GLASS-8
Size and description
Glass FT-cell 8mm outer diameter

Video Guides

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Quick Guide SULF Microsensors

We look into how SULF sensors are made, how they work, their specifications, and possible customizations.

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Quick Guide H2S Microsensors

Learn when to choose H2S over SULF, the applications as well as specifications and customizations.

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H2S Calibration Kit Video

Application Scientist Tage Dalsgaard shows you how to perform a 2-point calibration with H2S free water and one known H2S concentration

Related publications

Nitrite effectively inhibits sulfide and methane production in a laboratory scale sewer reactor
Mohanakrishnan, J. et al. (2008), Water Research, vol. 42, 3961-3971
Read more
An Amperometric Microsensor for the Determination of H 2 S in Aquatic Environments
Jeroschewski, Paul et al. (1996), Analytical Chemistry, vol. 68, 4351-4357
Read more
Silk Fibroin Porous Scaffolds Loaded with a Slow-Releasing Hydrogen Sulfide Agent (GYY4137) for Applicati⁠…
Raggio, Rosasilvia et al. (2018), ACS Biomaterials Science and Engineering, vol. 4, 2956-2966
Read more
Oxygen depletion and benthic mortalities: The first in situ experimental approach to documenting an elusive phenomenon
Stachowitsch, Michael et al. (2007), Limnology and Oceanography: Methods, vol. 5, 344-352
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