Ask The Expert Webinar Series
Explosives by HPLC, LC/MS and
LC/MS/MS
Karla Buechler – Corporate Technical Director
August 2, 2016
Presentation Outline A Historical Overview of
Explosive Chemicals
An Introduction to the
Chemistry and types of
Explosives
Explosive Chemicals in the
Environment
How are Explosives
Regulated?
Analytical Methodologies –
Method 8330B vs 8321
A Perchlorate Discussion
An ISM Discussion
TestAmerica’s Capabilities
History of Explosive
Chemical Discoveries Chinese alchemist discovered first
explosives in 9th century.
Roger Bacon (1220-1292) made
black powder from saltpeter, sulfur
and charcoal.
In 1353, Berthold Schwarz invented
the gun.
In 1845, Schonbein made
nitrocellulose (NC).
In 1860, Major Schultz made a
stable NC powder.
Nitroglycerin (NG) was discovered in
1846 by Ascanio Sobrero.
Cont. History of Explosive
Chemistry Discoveries
du Pont de Nemours in
1858 began production of
sodium nitrate.
Commercial production of
gun powder.
Alfred Nobel mixed NG
with silica and patented
dynamite in 1867.
1884, a smokeless gun
powder was developed as
a mixture of (NC) and ether
and alcohol, by Vieille.
What are Explosives?
2 Functional Classes of Explosives
1) High – Release large of amounts of
energy when detonated.
Primary – Used to start explosions
(Lead azide and Lead styphnate).
Secondary – Main charge TNT and RDX.
2) Low – Burn at steady speed and
detonate only under extreme
conditions.
A reactive substance that contains a great amount of potential
energy that can produce an explosion if released suddenly
Chemical Classes of
Explosive Compounds
TNT
C-NO2
Nitroaromatics
PETN
Nitrate esters
C-O-NO2
RDX
Cyclic nitramines C-N-NO2
Explosive Aromatics
(TNT, DNT, TNB)
Desirable features
include stability and
low sensitivity to
high temperature
Used in military
munitions and in
civilian mining
Relatively safe to
manufacture
TNT is toxic
Degradates are
routinely analyzed
GC and GCMS
are inadequate
IC, LC and LCMS
are preferred
Explosive Esters – (NC, NG,
PETN, EGDN)
All except NC are
highly sensitive
All are toxic
NC – primarily used in
smokeless powder
NG – main component of
dynamite
PETN – used as a
detonator
EGDN – additional
ingredient in dynamite
No degradation products of
concern
GC and GCMS
are inadequate
IC, LC and LCMS
are preferred
Explosive Nitramines
(RDX and HMX)
Very important military
explosive
Resistant to heat
High chemical stability
Explosive power much
greater than TNT
Often used in mixtures
Very shock sensitive
Very toxic
Concern about
metabolites
GC and GCMS
are inadequate
IC, LC and LCMS
are preferred
RDX/HMX Metabolites and
Degradation Products
Persistence in the environment
Human body can transform
RDX/HMX into metabolites
We know little about their
toxicity
We need reliable analytical
techniques in order to
remediate these chemicals
Why do we care?
Insensitive Munitions
(DNAN, NTO and NQ)
Do not react violently –
save lives and materials
In 2013, US Army
approved the use of IM
Used to replace or
supplement RDX, HMX
and TNT
Potential release to the
environment
USS Enterprise January 15,
1969 Flight deck accident We need analytical
methods
Other Explosive Chemicals
White Phosphorus – incendiary
purposes, burns spontaneously
in air
Tetracene – used in ammunition
primers to provide stability
Nitroguanidine - high explosive
like TNT
Perchlorate – rocket propellants,
consumer products
NDMA – liquid rocket fuels
Nitrocellulose – First smokeless
powder
Other Explosive Methods
White Phosphorus – Modified
8141 GC with NP detector
Tetracene – Method 8331
LC/UV or PDA detector
Nitroguanidine – Modified
Method 8330 unique polarity
Perchlorate – Method 8321 or
6850/60 IC or LC with MS/MS
NDMA – Method 521, 1625 or
625. All GC/MS techniques.
Nitrocellulose – Modified
Method 353.2
Explosive chemicals in the
Environment Production, storage, and disposal of explosives and
propellants at military installations and manufacturing facilities
Discharge of contaminated manufacturing waste streams into
rivers or ground water,
Burial of obsolete munitions,
Training exercises increase the availability of explosives to the
environment.
Environmental analytical methods were needed
to
Explosives Regulations
RDX, TNT, and
1,3-DNB listed in
UCMR2
NDMA included in
UCMR2
RDX & DNTs
included on DoD
MERIT list
Additional Regulatory
Guidance
RSEPA- Range Sustainability Environmental Program Assessment
RCA – Range Condition Assessment
CRE – Comprehensive Range Evaluation
SRO – Sustainable Range Oversight during a CERCLA response
Desirable Method
Characteristics
Linearity
Precision
Accuracy
Sensitivity
Selectivity
Robustness
Explosives compounds are unique – GC and
GCMS work poorly
IC LC
LC
MSMS
IC
MS
LC
MS
8330B - Primary Method for
Explosive Residue Analysis
Developed by USACE
CRREL laboratory in late
1980’s
Updated to 8330B in
November 2006
Originally for RDX, HMX,
Tetryl, NB, DNT, TNT
General use all purpose
method
EPA Method 8330
HPLC/UV, confirmation by
LCMS allowed
Pros and Cons of Method
8330B
Pros of HPLC/UV
Fairly simple technique
Moderately inexpensive
Reasonably rugged and
quick
Cons of HPLC/UV
Prone to false positives
Lack of sensitivity
No complex matrices
Limited analyte list
Advantages of Method
8321 vs 8330B
Sample preparation
very similar to 8330B
Mass spectrometer
reduces interferences
MS/MS mode is
available
Second column conf.
not necessary
Analyte list can be
significantly extended
Advantages of LC/MS/MS
Specificity/Selectivity - A target analyte’s response is
highly characteristic of its identity. LC/MS/MS analyses are
10 to 100 times better at filtering interferences than
conventional instrumentation
Sensitivity - Softer ionization than Electron Impact (EI)
GCMS – allows for thermally labile analytes to be detected
Ruggedness – improved reproducibility for a wide variety of
parameters and matrices and improved productivity
21
LC/MS/MS – Electrospray
Ionization
22
Perchlorate IC vs LC/MS/MS
EPA Methods 314.0 and SW 846-
9058
Both use Ion Chromatography
Limitations
Insufficient sensitivity,
selectivity and robustness
Solution
LC/MS, LC/MS/MS, IC/MS,
IC/MS/MS
Method 8321, Method 6850 or
Method 6860
All our MS/MS methods
Better sensitivity – less affected
by ionic strength
Definitive selectivity
Chasing Sources of
Uncertainty
Field sample
collection
Lab subsampling
Sample extraction
Instrumental
analysis
Surface Soil from Military
Training Range
What?
Explosives
Where?
< 2 mm particles
Particle interior &
exterior
Nugget effect?
Expected to be high
due to particulate
nature of the analytes
25
Pictures from USACE-Alan Hewitt
Incremental Sampling
26
Random starting
locations in first
grid Increment
collection point
Systematic Random Design
Surface Soil from
Military Training Range
27
USACE-Alan Hewitt
One Decision
Unit (DU)
Explosives Sample Pre-
extraction Steps
Goal - We need a small
representative sample
of a larger sample.
Drying
Disaggregation
Sieving
Milling
Subsampling
28
Air Drying of Soil Samples
29
High boiling
analytes
Disaggregation & Sieving
30
Mortar & Pestle
Mechanical chopping #10 Sieve
Soil Sample Milling
31
Picture from USACE-Alan Hewitt
Puck mill grinding
Smaller, better
mixed particles
Subsampling
2 D slabcake subsampling
32
Technical Summary
33
Study allowed for the comparison of a number of factors
that affected the reproducibility of results.
Factor A Factor B Comments
Field collection techniques
Discrete, box, and wheel
Avg RSD = 115%
ISM
Avg RSD = 22%
~5x better precision with
ISM
Laboratory subsampling and
milling
8330A
Avg RSD = 22%
8330B
Avg RSD = 6%
~3x better precision with
ISM
Advantages of ISM
Advantages
Better spatial coverage
Higher Sample Mass
Optimized processing
Fewer non-detects
More consistent data
Effects
Includes high & low conc. in
proper proportions
Reduces errors associated
with processing and analysis
Representative subsamples
Simplifies statistical analysis
More confident decision
34
Project Experience
Federal Program Support
US Army Corps of Engineers
US Navy
US Air Force
USGS
DOE
Example Project Locations Redstone Arsenal
Ft. McClellan
Ravenna Arsenal
Avon Park
Pueblo Chemical Depot
Iowa AAP
China Lake NAWS
Picatinney Arsenal
Benicia Arsenal
Dugway Proving Ground
Jefferson Proving Ground
Alleghany Ballistics Lab
Indian Head NSWC
JACADs
Weldon Springs
Pantex
TestAmerica Capabilities
3 laboratories accredited
by DoD ELAP for
8330B: Burlington,
Denver, Sacramento
LC/UV
LC/MS
LC/MS/MS
Dedicated ISM facilities
More than 25 years at each lab with explosives analysis
Capabilities for Complex
Matrices
37
Future Concerns
Need methods for
insensitive munitions
Need to expand
analyte lists for
existing methods
Need to develop
clean up techniques
for complex matrices
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