A new glow discharge plasma-based sensor is fabricated for specific detection of hydrogen (H2) at parts per billion (ppb) levels based on gas ionization process under vacuum condition (~0.01 torr). The system setup consists of a twoelectrode system including graphite electrode (diameter: 6.5 mm), modified with arc-synthesized carbon nanostructures as anode and an aluminum disk with 2.4 mm diameter as cathode with inter-electrodes distance of 700±10 μm inside a glass chamber. For H2 detection, ionization current is considered as detection system, during applying an 853-V direct current potential as a fingerprint breakdown voltage for H2 ionization to the electrodes. According to the results, the sensor is linear ranging from 40 to 86 ppb. The relative standard deviation of nine replicate analyses during introduction of ~60 ppb of H2 is 2.57 %. Also, the detection limit is evaluated to ~3.3 ppb. No interfering effect is observed when introduction of at least 1000- fold excess (mass/mass) of foreign species such as Ar, He, CO2, CO, C2H2, O2, acetone, and CH3OH to ~60 ppb of H2 standard solution. Reliability of the sensor is also evaluated via determination of H2 in two industrial gas samples.
کلید واژگان :Carbon nanotubes, Glow discharge plasma,
ارزش ریالی : 600000 ریال
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