Hm. Cai et al., PULSED DISCHARGE ELECTRON-CAPTURE DETECTOR OPERATING IN THE CONSTANT-CURRENT MODE BY MEANS OF FEEDBACK DC BIAS VOLTAGE, Analytical chemistry (Washington), 70(18), 1998, pp. 3770-3776
A feedback de bias voltage has been utilized to established a constant
-current operation mode (cc-mode) for the pulsed discharge electron ca
pture detector (PDECD). The feedback voltage is directly proportional
to the concentration of analyte in the detector cell and can function
as output. Working in this mode, the PDECD has a linear dynamic range
of 1 x 10(5) for CCl4 and 1 x 10(4) for pesticide-almost 1 order of ma
gnitude better than in the previously documented constant-potential mo
de (cp-mode). The minimum detectable quantity for CCl4 is 1.5 fg (10(-
15) g) and for lindane, 16 fg, This paper compares the operation of th
e PDECD in the cc-mode and in the cp-mode, Our findings indicate that
a PDECD operating in the cc-mode has relative response, temperature de
pendence, and dopant gas effects similar to a PDECD in the cp-mode und
er the same experimental conditions, but has advantages of higher sens
itivity, faster response, and simpler operation.