App note-Analysis of drugs of abuse and explosives by GCMS
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Updated date
11 January 19
Title
App note-Analysis of drugs of abuse and explosives by GCMS
Keywords
Analysis, of ,drugs, of, abuse, and, explosives, by, GCMS, Article, Ed, Connor
Product Range
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Language
UK English
Company Brand
Peak Scientific
Extracted text
Your local gas generation partner
Analysis of drugs of abuse
and explosives by GC-MS
www.peakscientific.com
Analysis of drugs of
abuse and explosives
by GC-MS
Ed Connor Dr. Sc.
GC-MS Application Specialist
Background
Researchers from Prof. Guido Verbeck’s group
at the University of North Texas (UNT) carried
out analysis of drugs of abuse (DOA) and
explosives using an ion trap GC-MS to compare
results when using helium and hydrogen carrier
and buffer gas. As well as comparing the two
gases, the group also assessed a number of
ion volumes with different orifice diameters
to look at their effect on sensitivity with either
gas.
With hydrogen increasingly being used as
an alternative to helium for a number of
GC analyses, this study will be of particular
interest to forensic scientists analysing DOA
and energetic materials by GC-MS. The paper,
published in the journal Science & Justice can
be downloaded from:
http://dx.doi.org/10.1016/j.scijus.2015.01.003
1
Materials & Methods
A 1mg/mL in methanol standard mixture of drugs
(cocaine, phenolbarbitol, codeine, oxycodone
and diazepam) was purchased and explosive
compounds (Pentaerythritoltetranitrate-(PETN),
Triacetonetriperoxide-(TATP), ethylene glycol
dinitrite-(EGDN), cyclotrimethylenetrinitramine
(RDX), trinitrotoluene-(TNT), dinitrotoluene(DNT), Methyl ethyl ketone peroxide-(MEKP)
and hexamethylenetriperoxidediamine-(HMTD))
synthesised in the lab.
Analysis was conducted using a Thermo
Focus GC with a Polaris-Q MS fitted with a 1
cm quadrupole ion trap, allowing replacement
of the ion volumes without breaking vacuum.
Helium was supplied via a helium tank and
hydrogen supplied by a Peak Scientific
Precision Hydrogen Trace 500cc generator.
Ion volumes with exit orifice diameters of
1,2,4,6,8 & 10mm were machined for use in the
Polaris-Q MS.
GC & MSD Conditions
GC Parameters
Oven Temp
Oven Ramp
Inlet temp
Split flow
Column
Transfer line temp
Explosive Analysis
Drug Analysis
40°C - 300°C (3 min hold) 70°C - 300°C (3 min hold)
10°C/min
20°C/min
250°C
250°C
20 mL/min
Splitless
RTX1 (15m x 0.25 mm x 0.1m)
300°C
MSD Parameters
Explosive Analysis
Drug Analysis
m/z 28-650: PETN, TATP,
EGDN, RDX (Helium) &
HMDT
m/z 40-350: All
compounds
m/z 50-650: TNT, DNT,
RDX (Hydrogen)
m/z 33-350: MEKP
200°C
25ms
25µs
25µs
Mass range
Source temperature
Maximum ion time
Ionisation time
Results
Drug analysis: No difference was observed in the
ion spectral patterns of cocaine, phenolbarbitol,
codeine or oxycodone. Even though these
compounds have electron rich Nitrogen and
Oxygen species, their fragmentation patterns
remain unchanged regardless of carrier gas used.
Of the drugs tested, only diazepam showed a
different fragmentation pattern depending on
whether Hydrogen or Helium was used.
Explosives analysis: Of the 8 explosives
analysed, PETN, TATP, EGDN and RDX
exhibited no difference in fragmentation.
TNT, DNT, MEKP and HMTD did display some
difference in fragmentation pattern when run
with Hydrogen compared with Helium.
Effect of Ion volume on sensitivity: All 6 ion
volume sizes (1,2,4,6,8 & 10mm) were assessed
for each compound with both hydrogen and
helium carrier gas (figure 1A & 1B). Cocaine’s
primary fragment (m/z 182.04) was used to
compare intensities of each ion volume size
using hydrogen and helium. Results showed
the 10mm ion volume produced the highest
intensity for both hydrogen and helium carrier
gas, with the 6mm ion volume producing the
lowest intensity. The other ion volume orifice
results were inconsistent between the two
carrier gases.
Conclusions
Results from the analysis of drugs and explosives
show that the majority of compounds did not
fragment differently regardless of whether
hydrogen or helium carrier gas was used. The
advantages that hydrogen offers as a cheap
carrier gas include faster, improved analysis
compared with helium, make these results
even more attractive to labs analysing drugs
and explosives.
Figure 1. Effect of ion volume orifice on signal intensity of Cocaine’s
primary fragment ion (m/z 182.04) when used with helium (Figure 1A)
and hydrogen (Figure 1B).
Reference
Chinyere N. Nnaji, Kristina C. Williams, Jonathan
M. Bishop, Guido F. Verbeck (2015) Science and
Justice 55: 162-167
Ed Connor Dr.Sc. is a GC-MS Application Specialist,
Peak Scientific, Inchinnan Business Park, Scotland,
UK . Prior to joining Peak, Ed completed his Dr.Sc. at
ETH Zurich in Switzerland using GC-MS to look at
herbivore induced plant volatiles and their interaction
with beneficial insects. He then joined the University
of Zurich where his work focused primarily on volatile
collection methods and analyses using GC-MS and GC-FID.
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