Instruction manual

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 H
2
S SO
2
NO NO
2
Cl
2
H
2
HCN HCl NH
3
Ethyl-
ene
PH
3
Carbon
monoxide
(CO)
100 < 3 0 < 10
≤ - 20
< 10 < 40 < 15 0 0 < 100
Hydrogen
sulfide (H
2
S)
< 10 100 < 20 0
~ − 20 ~ − 20
< 0.1 0 0 0 0
“CO Plus”
(Cal to CO)
100
∼ 350 ∼ 50 ∼ 25 − 60 ∼ − 40 < 40 ∼ 40 ∼ 5
“CO Plus”
(Cal to H
2
S)
25 100
∼ 15 ∼ 6 − 15 ∼ − 10 < 15 ∼ 10 ∼ 1
Sulfur
dioxide
(SO
2
)
0 0 100 0
~ −100
- 5 0 < 50 0 0 0
Nitric oxide
(NO)
0 ~ 35 ~ 5 100 < 40 0 0 0
≤ 15
0 0
Nitrogen
dioxide
(NO
2
)
0
~ −
20
< −
0.5
0 100
≈100
0 0 0 0 0
Chlorine
(Cl
2
)
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
≤ 2
100
Ammonia(N
H3)
(-04 Version)
0 ~ 100 ~ 60 ~ 20 0 ~ 50 0 ~ 5 0 100
1
Data derived in part from City Technology Limited, Product Data Handbook
Oct. 1, 1992