U.S. flag An official website of the United States government

On Oct. 1, 2024, the FDA began implementing a reorganization impacting many parts of the agency. We are in the process of updating FDA.gov content to reflect these changes.

U.S. Food and Drug Administration
  1. Home
  2. Food
  3. Science & Research (Food)
  4. Laboratory Methods (Food)
  5. BAM R51: O/129 Disks (2,4-Diamino-6,7-diisopropyl pteridine)
  1. Laboratory Methods (Food)

BAM R51: O/129 Disks (2,4-Diamino-6,7-diisopropyl pteridine)

Reagents Index for BAM

January 2001

2,4-Diamino-6,7-diisopropyl pteridine (O/129) or phosphate salt
Distilled water, sterilized
Filter paper disk blanks, 5-6 mm or 1/4 inch, sterilized
Micropipettor, calibrated to deliver 10 1

Mark disks to differentiate 10 g from 150 g disks. Sterilize filter paper disks in glass petri plates. Dissolve O/129 or O/129-PO4 (the phosphate salt dissolves more easily) in sterile water. For 150 g disks, place 10 1 of 15 mg/ml O/129 or 20.8 mg/ml O/129-PO4 on each disk. For 10 g disks, make l:l5 dilutions of the O/129 solutions and place 10 1 l of 1.O mg/ml O/129 or 1.4 mg/ml O/129-PO4 on each disk. Dry disks and store desiccated and protected from light in refrigerator. O/129 disks are commercially available.

Original Source: Bacteriological Analytical Manual, 8th Edition, Revision A, 1998.

Back to Top