Explosive analysis

Question 1

TEA (thermal energy analyser)

Answer 1

uses specific reaction with ozone. NO2 group essential for this method
- picogram LoD
- simple
- fast and reliable
- robust evidence

Question 2

what are the 3 columns used in TEA

Answer 2

1. BP1 - non polar = detects nitro groups
2. BP5 - slightly polar = shifts retention times
3. CPSIL19 - polar = further shifts and separates more

Question 3

Relative retention time

Answer 3

RRT = RT unknown / RT reference compound

Question 4

% retention time difference

Answer 4

RRT sample - RRT std / RRT std x 100
can confirm identity if %RT diff < 0.50%

Question 5

explosive quantification
1. mass sample injected=
2. total mass of sample=

Answer 5

• mass sample injected = mass standard injected x (peak sample/ peak std)
• total mass of sample = mass injected x (total volume of sample/ volume injected)

Question 6

SEM EDX

Answer 6

• non destructive
• area mapping - for sample homogeneity
• useful for metals

! not highest sensitivity
! only gives element oxidation state

Question 7

xray photoelectron spectroscopy

Answer 7

• higher sensitivity
  ! not used for mapping
• ion chromatography - separates based on charge
• capillary electrophoresis - e- field separates based on size and charge