58
Appendix E PhD Ultra Toxic Sensor Cross Sensitivity Data
1
The table below lists the cross sensitivity of electrochemical toxic sensors used in Biosystems portable gas detectors to
gases other than their target gas. Depending on the nature of the reaction each gas has with the sensor, the effect can
either decrease the signal (negative cross sensitivity) or increase the signal; (positive cross sensitivity). Each figure
represents the reaction of the sensor to 100 ppm of gas, thus providing a percentage sensitivity to that gas relative to its
target gas.
The table below lists the cross sensitivity of electrochemical toxic sensors used in Biosystems portable gas detectors to
gases other than their target gas. Depending on the nature of the reaction each gas has with the sensor, the effect can
either decrease the signal (negative cross sensitivity) or increase the signal; (positive cross sensitivity). Each figure
represents the reaction of the sensor to 100 ppm of gas, thus providing a percentage sensitivity to that gas relative to its
target gas.
CO
H2S SO2 NO NO2 Cl2
H2 HCN HCl NH3 Ethyl-
ene
PH3
Carbon
monoxide
(CO)
100
< 3
0
< 10
d
- 20
< 10
< 40
< 15
0
0
< 100
Hydrogen
sulfide (H2S)
< 10
100
< 20
0
~
20
~
20
< 0.1
0
0
0
0
“CO Plus”
(Cal to CO)
100
a
350
a
50
a
25
60
a
40
40
a
40
a
5
“CO Plus”
(Cal to H2S)
25 100
a
15
a
6
15
a
10
15
a
10
a
1
Sulfur
dioxide
(SO2)
0 0 100 0
~
100
- 5
0
< 50
0
0
0
Nitric oxide
(NO)
0
~ 35
~ 5
100
< 40
0
0
0
d
15
0 0
Nitrogen
dioxide
(NO2)
0
~
20
<
0.5
0 100
|
100
0 0 0 0 0
Chlorine
(Cl2)
0
~
20
0 0 120
100 0 0 0 0 0
Hydrogen
cyanide
(HCN)
< 3
~ 600
~ 395 0 ~
120
~
140
0 100 ~
35 -
5 ~
25
Phosphine
(PH3)
-
~ 25
< 0.1
d
2
100
Ammonia(N
H3)
(-04 Version)
0
~ 100
~ 60
~ 20
0
~ 50
0
~ 5
0
100
1Data derived in part from City Technology Limited, Product Data Handbook Oct. 1, 1992
