A novel gas phase titrimetry is introduced for acetylene (C2H2) determination at parts
per million (ppm) levels based on the non-thermal glow discharge plasma-based
ionization of hydrogen (H2) standard solution. For this purpose, a constant flow of H2
solution is introduced to an ionization chamber containing a fixed volume of C2H2
solution. The end point (EP) of the titration is indicated by the image processing of the
plasma generated between a two-electrode system including Al rod as anode and multiwalled
carbon nanotubes (MWCNTs) as cathode using a charged coupled device
(CCD) camera during applying a fixed breakdown voltage (832±1 V). According to the
results, the ratio of CH2/[C2H2] is evaluated to 2.34±0.01. No interference is observed
during introduction of at most 1000 folds excess of various foreign gas species to a
fixed solution of acetylene (~5.0 ppm). Only a constant negative error to ~-8% is
evaluated due to the multi-step reaction of hydride (H-) as the ionization form of H2
with C2H2. This method is also considered as an analytical technique that is adopted for
standardization of H2 standard solution at parts per billion levels. Finally the reliability
of the method is validated via analyses of two real samples.
کلید واژگان :
Gas phase titrimetry; Breakdown voltage; Glow-discharge plasma;
