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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Explosives by HPLC, LC/MS, and LC/MS/MS

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