Tải bản đầy đủ - 0 (trang)
5 Examination of Evidence to Prove Icing (Step IV)

5 Examination of Evidence to Prove Icing (Step IV)

Tải bản đầy đủ - 0trang

Fig. 20.8 A jar containing a biphasic solution recovered

from a clandestine crime scene. Organic layers are tested for

methamphetamine when the pH of the aqueous layer is above

7 (basic).



Fig. 20.9 A biphasic solution containing a neutral aqueous layer.

In this case, both layers are tested for methamphetamine.



Fig. 20.10 Iced

methamphetamine crystals.

Acetone is usually a critical

source of evidence because it is

required in the icing stage of

methamphetamine production.



20.6



20.6



Examination of Stains



277



Examination of Stains (Fig. 20.11)



Characteristic stains related to the clandestine production of methamphetamine are usually red, brown, or yellow in color.

They are often found on fabric, clothing, plastic tubing, filter paper, carpet, floors, and walls (Fig. 20.12).

1. Collect a small sample of the stain and dissolve in 1 ml of water. Test pH of the solution.

2. If basic, perform extraction with hexane for GCMS.

3. If acidic, test for acid type using the silver nitrate test.

4. Test the acidic solution for the presence of iodine using starch test or chloroform test.

5. Perform base extraction in hexane for GCMS.



Fig. 20.11 Summary of

forensic examination of stain

evidence.



Fig. 20.12 Stains characteristic

of methamphetamine production.

The patterns are highly variable

but the colors are usually red,

brown, or yellow. Stains can be

found on anything used in the

production process or on

contaminated material or fabric

in the local vicinity.



278



20.7



20



Examination of Clandestine Evidence



Examination of Washes



Washing is typically performed using methanol or water; however, water is usually preferred as discussed in Chap. 19. The

procedure for examining washes is illustrated in the flowchart in Fig. 20.13, regardless of solvent (Fig. 20.13).

Fig. 20.13 (a) Glassware

collected from clandestine sites

is tested for the presence of

methamphetamine using washes.

(b) The residue is dissolved in

water and the resulting solution

is tested using the flowchart.



20.8



20.8



Determining Methods of Methamphetamine Production



279



Determining Methods of Methamphetamine Production



Criminal prosecution requires proof that individuals engaged in the production of illicit drugs. Although the actual method

used is often of little concern, identifying the process is necessary to prove unlawful activity.

The simple observation of chemicals and equipment discovered at the scene is one way to identify the method used to

produce methamphetamine. For example, the Nazi method would be suspected if sodium (Na) or lithium (Li) is discovered

with a conspicuous absence of heat sources (cold method), whereas the Red-P/HI method would be implicated by the presence of red phosphorus, hydroiodic acid, and heat sources (hot method).

A significantly more reliable way to determine the method of production is through the use of analytical results. Individual

methods yield a set of distinctive by-products that are used to identify the process. For example, Red-P/HI reduction produces a set of by-products that are different from those found in Nazi reduction. In addition, reduction methods using ephedrine or pseudoephedrine as precursors generate different by-products than those using the ephedra plant

(Figs. 20.14–20.16).



Abundance

4000000

3500000

3000000

2500000

2000000

1500000

1000000

500000

0



3.00



4.00



5.00



6.00



7.00



8.00



9.00 10.00 11.00 12.00 13.00 14.00



Time



58



Abundance

9000

8000

7000

6000

5000

4000

3000

2000

1000



41



0



53



65 7074 79



9195



103

115

108 119



134



148

152



20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100105110115120125130135140145150155160

m/z



58



Abundance

9000

8000

7000

6000

5000

4000

3000

2000

1000

0



Fig. 20.14 Signature GCMS

results of the Nazi method.



42



51



91

101 109 119

65 70 77 81 86

95

105 115



134

130



150

146



30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 145 150 155 160

m/z



280

Fig. 20.15 Signature GCMS

results of the HI-red phosphorus

method.



20



Examination of Clandestine Evidence



Abundance

4000000

3500000

3000000

2500000

2000000

1500000

1000000

500000

0



4.00



6.00



8.00



10.00



12.00



14.00



Time



Abundance



43



9000

8000

7000

6000

5000

4000

3000

2000

1000

0



91



134



65

51



5761



73 77



103



86



115119



35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140

m/z

Abundance

8000



146

Aziridine, 1,2-dimethyl-3-phenyl-, trans- (*)



6000



105



42



4000



15

2000



132



91



28

51



65

63



77



117

115



12



0



20



40



60



80

m/z



100



120



Abundance

9000

8000

7000

6000

5000

4000

3000

2000

1000

0



148

140



232

217



1, - Dimethyl-2-phenyl-naphthalene



202

101

41



51



65 77 91



115

128139



155

165176



189



281



40 50 60 70 80 90 100 110 120 130 150 160170 180 190 210 220 230 240 250 260 270280

m/z



Tài liệu bạn tìm kiếm đã sẵn sàng tải về

5 Examination of Evidence to Prove Icing (Step IV)

Tải bản đầy đủ ngay(0 tr)

×