At temperatures between 170 and 240 ◦C, Eq. (1a) dominates
and exothermic decomposition takes place. At higher temperatures,
reaction according to Eq. (3) occurs, which can lead to
detonation and explosion as shown by Eqs. (4) and (5) [27]. Following
these equations, samples of ammonium nitrate (labeled and
non-labeled) were heated in two groups. Group 1 was heated at
200 ◦C for 10 min and group 2 was heated using a small blow torch
(blue flame ∼ 1200 ◦C) during a few seconds without temperature
control. Upon analysis by GC/MS and extracting ions 44 and 45 it
was found that the yield did not exceed 5% for N2O, 15N2O in group
1 and 15N2O in group 2. Further heating of the samples from group
1 at 200 ◦C and 1200 ◦C did not improve this yield. Non-labeled
nitrous oxide from group 2 achieved a recovery yield as high as
27%. It was noted that small samples did not follow the exothermic
reaction as expressed in Eq. (1a) [28], but in fact, ammonium
nitrate decomposed endothermically via Eq.(2). Due to the inability
to improve the recovery yield by reacting in bulk, or purify the gas
generated,the use of generated 15N2O was dismissed for this study.
Wanting to present a simple yet effective procedure for N2O analysis,
hydrogen sulfide was selected.With each compound presenting
close molecular mass (34 and 44 g/mol), under gaseous state at
standard temperature and pressure and as tri-atomic species, H2S
appeared to be a satisfactory choice. Although our laboratory is not
well equipped to generate N2O and 15N2O in bulk safely, the use of
labeled nitrous oxide remains the most specific internal standard
for N2O analysis. The generation of N2O from thermal decomposition
of ammonium nitrate is possible but very difficult to control
under laboratory conditions.
At temperatures between 170 and 240 ◦C, Eq. (1a) dominatesand exothermic decomposition takes place. At higher temperatures,reaction according to Eq. (3) occurs, which can lead todetonation and explosion as shown by Eqs. (4) and (5) [27]. Followingthese equations, samples of ammonium nitrate (labeled andnon-labeled) were heated in two groups. Group 1 was heated at200 ◦C for 10 min and group 2 was heated using a small blow torch(blue flame ∼ 1200 ◦C) during a few seconds without temperaturecontrol. Upon analysis by GC/MS and extracting ions 44 and 45 itwas found that the yield did not exceed 5% for N2O, 15N2O in group1 and 15N2O in group 2. Further heating of the samples from group1 at 200 ◦C and 1200 ◦C did not improve this yield. Non-labelednitrous oxide from group 2 achieved a recovery yield as high as27%. It was noted that small samples did not follow the exothermicreaction as expressed in Eq. (1a) [28], but in fact, ammoniumnitrate decomposed endothermically via Eq.(2). Due to the inabilityto improve the recovery yield by reacting in bulk, or purify the gasgenerated,the use of generated 15N2O was dismissed for this study.Wanting to present a simple yet effective procedure for N2O analysis,hydrogen sulfide was selected.With each compound presentingclose molecular mass (34 and 44 g/mol), under gaseous state atstandard temperature and pressure and as tri-atomic species, H2Sappeared to be a satisfactory choice. Although our laboratory is not
well equipped to generate N2O and 15N2O in bulk safely, the use of
labeled nitrous oxide remains the most specific internal standard
for N2O analysis. The generation of N2O from thermal decomposition
of ammonium nitrate is possible but very difficult to control
under laboratory conditions.
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