Teledyne T200H User Manual page 268

Principles of Operation
PMT
Response
266
*
NO
2
All things being constant, the relationship between the amount of NO present in the
reaction cell and the amount of light emitted from the reaction is very linear. More NO
produces more light, which can be measured with a light-sensitive sensor in the near-
infrared spectrum (Figure 8-1). In order to maximize the yield of reaction (1), the
T200H/M supplies the reaction cell with a large, constant excess of ozone (about 3000-
5000 ppm) from the internal ozone generator.
Model 200E Instrument Response
Intensity
140 a.u.
120 a.u.
100 a.u.
80 a.u.
60 a.u.
40 a.u.
20 a.u.
0 a.u.
0.5µm 0.7µm
M200EH/EM
Sensitivity Window
Figure 8-1:
However, only about 20% of the NO
excited state. In addition, the excited NO
the reaction cell (mostly other molecules but also cell walls) and transfer its excess
energy to its collision partner without emitting any light at all (Equation 9-3). In fact, by
far the largest portion of the NO
percent yield of usable chemiluminescence.
*
NO +
2
In order to enhance the light yield of the reaction, the reaction cell is maintained at
reduced pressure. The probability of a collision between the NO
collision partner M increases proportionally with the reaction cell pressure. This non-
radiating collision with the NO
unwanted process further described in Section 8.2.4.2.
Teledyne API - Model T200H/T200M Operation Manual
→
ν
NO + h
2
( Equation 8-2)
Optical Hi-Pass Filter Performance
0.9µm 1.1µm 1.3µm
Wavelength
T200H/M Sensitivity Spectrum
that is formed through reaction 10-1 is in the
2
can collide with another collision partner M in
2
* returns to the ground state this way, leaving only a few
2
→
M NO +
2
* molecules is usually referred to as quenching, an
2
NO + O Emission Spectrum
3
1.5µm 1.7µm 1.9µm
M
* molecule and a
2
07270D DCN7141
(Equation 9-3)