Summary
An ECD with a nitrogen-n-pentane mixture as purging gas was used for analysis of pesticides. The role of purging gas is explained on the basis of higher ionization cross-section and the broader spectrum of excitable states leading to effective slow-down reactions and absence of highly energetic metastable states. A linearity of 0.85 over the applied linear dynamic range from 10−9 to 10−12 was measured. The lowest detectable amount of 2.5×10−13 g Aldrin at 0.5 nA standing current or 5.0×10−14 g Aldrin at 1.0 nA respectively was achieved.
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Abbreviations
- β:
-
primary electrons
- β′:
-
slow primary electrons
- e:
-
secondary electrons
- e′:
-
secondary electrons of thermal energy
- Ar+ CH +4 :
-
ionic forms of argon, methane and pentane
- C5H +2 :
-
superexcited long-lived states of argon and nitrogen respectively
- Arm :
-
metastable state of argon
- Ar′, N ′2 :
-
deexcitated states of argon and nitrogen respectively
- N x2 , CH x4 :
-
excitable electronic, vibrational and rotational
- C5H x12 :
-
states of nitrogen, methane and pentane molecules respectively
- Z:
-
third body
- I.P.:
-
ionization potential
- E.P.:
-
excitation potential
- Qc :
-
ionization cross-section of c
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Ševčík, J. Nitrogen-n-pentane mixture as a purging gas for electron capture detectors. Chromatographia 10, 601–603 (1977). https://doi.org/10.1007/BF02265038
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DOI: https://doi.org/10.1007/BF02265038