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April 1999 Volume 1
Number 1
Chapter 4 of Forensic
Fiber Examination Guidelines
Appendix A:
Suggested Standard Dye Mixtures
Standard dyes should be used
to check eluent performance. The following list suggests some
suitable mixtures but is not totally inclusive or exclusive.
Any (simple) mixture of dyes separating in these eluents can
be used.
Recommendations for Preparation
of Standard Dye Mixtures:
Approximately 5 mg of each dye component is made up to a final
volume of 25 mL with pyridine/water (4:3 v/v). Use until the
supply is exhausted.
Solution A for eluents 1, 2, 3, 4, 9, 10, 12
Solway green G (CI Acid Green 25), Solway blue RNS (CI Acid Blue
47) and Naphthalene fast orange 2GS (CI Acid Orange 10).
Solution B for eluents 5, 7, 8
Supracet fast orange G (CI Disperse Orange 3), Supracet fast
violet B (CI Disperse Violet 8) and Supracet scarlet 2G (CI Disperse
Orange 1)
Solution C for eluent 6
Supracet fast orange G (CI Disperse Orange 3) and Supracet fast
violet B (CI Disperse Violet 8).
Solution D for eluent 11
Solway green G (CI Acid Green 25), Supracet fast orange G (CI
Disperse Orange 3) and Supracet fast violet B (CI Disperse violet
8).
Testing of Eluents and
Extraction Solutions
Checks are carried out prior to use on eluent performance, and the extractants
are tested to ensure that they have not been contaminated. Suggested TLC
plates are Merck DC Alufolien Kieselgel 60F254 (7.5 × 5.0 cm). The
standard dye and extraction solution are spotted side by side onto a TLC
plate that rests on a hot plate set at approximately 70°C or is dried
with a heat source such as a blow-dryer. They are spotted 1 cm from the
base and eluted as described in section
7.0 (Analysis; click to view) of Chapter 4. The chromatogram is compared
with previous stored tests to ensure that the separation is acceptable
and that there are no visible bands obtained from the extraction solution.
If unacceptable, fresh eluent/extractant is made and tested.
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FORENSIC SCIENCE COMMUNICATIONS APRIL 1999 VOLUME 1 NUMBER 1 |
