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The
PID detector consists of a special UV lamp mounted on a thermostatted low
volume flow-through cell. The temperature is adjustable from ambient
to 250ºC. The 10.6 electron volt UV lamp emits energy at a wavelength
of 120 nanometers, which is sufficient to ionize most aromatics ( benzene,
toluene, xylene, etc. ) and many other molecules ( H2S, hexane, ethanol
) whose ionization potential is below 10.6 ev. Methanol and water,
for instance, have ionization potentials greater than 10.6 ev and do not
respond on the PID. Unlike other PID designs, the lamp on the SRI
PID can be removed easily without tools for periodic cleaning of the lamp
window. Lamps last far longer on the SRI PID because only the lamp window
is heated, not the entire body of the lamp. Detection limits for
aromatics are
in the low picogram range ( ppb ) and because the PID is non-destructive,
it is often run in series with another detector ( FID/DELCD ) for multiple
chromatograms from a single
injection.
Use of the PID is mandated in several EPA methods ( 8021, TO-14 etc. )
because of its sensitivity and selectivity. The PID is also able
to run on air carrier, which can be useful in situations where no gas (
helium, hydrogen, nitrogen ) is available, or stream monitoring applications
where no column is used to separate compounds but rather the entire stream
of sample is directed through the detector.
8690-0040 PID detector with 10.6 ev
lamp $3,495.00 |
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