GSR

Question 1

What are the four main components of a bullet?

Answer 1

Case, Primer, Gunpowder, Projectile

Question 2

What are the three key primer metals analyzed in GSR?

Answer 2

Lead (Pb), Barium (Ba), Antimony (Sb)

Question 3

What type of GSR is derived from primer compounds?

Answer 3

Inorganic GSR (IGSR)

Question 4

What type of GSR comes from propellant additives?

Answer 4

Organic GSR (OGSR)

Question 5

Which test detects nitrites in gunshot residue?

Answer 5

Modified Griess Test

Question 6

What color indicates a positive Griess test?

Answer 6

Orange

Question 7

Which test detects lead in gunshot residue?

Answer 7

Sodium Rhodizonate Test

Question 8

What color change confirms lead in the Rhodizonate test?

Answer 8

Pink to blue-violet with HCl

Question 9

What is the visible GSR pattern in a contact shot?

Answer 9

Vaporous lead, tearing/burning of fabric, heavy soot

Question 10

What is the typical range for close-range gunshots?

Answer 10

Within 12 inches

Question 11

What is the typical range for intermediate-range gunshots?

Answer 11

12–24 inches

Question 12

What test is used when the clothing is dark and color tests are hard to see?

Answer 12

Benchkote or filter paper lift method

Question 13

What tool is used to examine particle morphology in GSR?

Answer 13

Scanning Electron Microscope (SEM)

Question 14

What tool is used to determine the elemental composition of GSR particles?

Answer 14

Energy Dispersive X-ray Spectroscopy (EDS)

Question 15

What does it mean if Pb, Ba, and Sb are found with spherical morphology?

Answer 15

Conclusive evidence of primer residue

Question 16

What are some sources of false positives in GSR tests?

Answer 16

Fertilizer, cosmetics, tobacco, urine

Question 17

What is “drop-off distance” in GSR analysis?

Answer 17

The maximum range GSR particles can travel and be detected

Question 18

What does the absence of GSR on a subject mean?

Answer 18

May not have fired OR residue was removed/blocked/degraded

Question 19

Which test was historically used to detect nitrates on hands?

Answer 19

Diphenylamine Test

Question 20

What is the main limitation of OGSR in forensic analysis?

Answer 20

It is chemically unstable and degrades over time

Question 21

What is the purpose of conducting standard distance test fires?

Answer 21

To compare GSR patterns to determine shooting distance

Question 22

What are the three primary categories of GSR testing methods?

Answer 22

Visual/microscopic examination, chemical enhancement, instrumental analysis

Question 23

What does the Modified Griess Test detect?

Answer 23

Nitrites from partially burned gunpowder

Question 24

What is the visual indicator of a positive Griess Test?

Answer 24

Orange azo dye on chemically treated paper

Question 25

What does the Sodium Rhodizonate Test detect?

Answer 25

Lead residue

Question 26

Why are Benchkote or filter paper lifts used in GSR testing?

Answer 26

To visualize color reactions on dark clothing or difficult surfaces

Question 27

What is the best method for conclusive detection of primer residue?

Answer 27

SEM-EDS (Scanning Electron Microscopy with Energy Dispersive X-ray Spectroscopy)

Question 28

What does SEM detect in GSR particles?

Answer 28

Morphology (shape and surface features)

Question 29

Why is LC-MS preferred over GC-MS for OGSR analysis?

Answer 29

OGSR compounds degrade thermally and are unstable in gas chromatography

Question 30

What other instrumental methods are used for GSR analysis besides SEM-EDS?

Answer 30

ICP-MS, LC-MS, LC-UV, capillary electrophoresis