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Transpector MPH Operating Manual
The appearance potential for Ar
2+
is 43.5 eV, and the ion production rate does not
maximize until the electron energy exceeds 100 eV. The appearance potential for
Ar
3+
is approximately 85 eV, while the appearance potential for Ar
4+
is over 200 eV.
4.1.1.4 A Qualitative Interpretation Guide
To use Transpector MPH to identify unknown substances, three characteristics
must be recognized:
fragmentation patterns
multiply charged ions
isotope ratios
Simple spectra are, in general, relatively easy to interpret and will yield useful
identifications. The analysis of complicated mixtures of substances is much more
difficult.
is intended as a spectrum interpretation guide which may be of use when
first examining an unknown spectrum. The guide lists the masses of peaks,
possible ion identities for each of these masses, and common sources for each of
these ions.
NOTE:
This list is not all-inclusive.
Table 4-3 Spectrum Interpretation Guide
Spectrum Interpretation Guide
AMU #
Chemical Symbol
Sources
1
H
water F or hydrogen F
2
H
2
, D
hydrogen, deuterium (
2
H)
3
HD,
3
H
hydrogen-deuterium, tritium (
3
H)
4
He
helium
5
No known elements
6
C
doubly ionized
12
C (Rare)
7
N
DI
14
N (Rare)
8
O
DI
16
O (Rare)
9
No known elements
10
Ne,
10
B
DI
20
Ne (Rare), BF
3
, BCl
3
11
Ne,
11
B
DI
22
Ne (Rare),
11
BF
3
, BCl
3
12
C
carbon, carbon monoxide F, carbon dioxide F
13
CH,
13
C
methane F, carbon isotope
14
N, CH
2
nitrogen, methane F or Note 1