Standard Reference Materials
Ampoule Specifications and Opening Procedure
|Table 1. Ampoule specifications for NIST SRM
|Body outside diameter
||(16.5 ± 0.5) mm
||(0.60 ± 0.04) mm
||Less than 2.5 %
||Less than 0.02 %
|Other heavy elements
Recommended Procedure for Opening the SRM Ampoule
- If the SRM solution is to be diluted, it is recommended that the diluting solution have a composition comparable to that of the SRM solution.
- Wear eye protection, gloves, and protective clothing and work over a tray with absorbent paper in it. Work in a fume hood. In addition to the radioactive material, the solution may contain a strong acid or base and could be corrosive.
- Shake the ampoule to wet all of the inside surface of the ampoule. Return the ampoule to the upright position.
- Check that all of the liquid has drained out of the neck of the ampoule. If necessary, gently tap the neck to speed the process.
- Holding the ampoule upright, score the narrowest part of the neck around its entire circumference with a scribe or diamond pencil.
- Lightly wet the scored line. This reduces the crack propagation velocity and makes for a cleaner break.
- Hold the ampoule upright with a paper towel, a wiper, or support jig. Using a paper towel or wiper to avoid contamination, snap off the top of the ampoule by pressing the narrowest part of the neck away from you while pulling the tip of the ampoule towards you.
- Transfer the solution from the ampoule using a pycnometer or a pipet with dispenser handle.
NEVER PIPETTE BY MOUTH.
- Seal any unused SRM solution in a flame-sealed glass ampoule, if possible, to minimize the evaporation loss.
Radioactive Standard Reference Material (SRM) Storage and Handling
- The SRM should be stored and used at a temperature between 5 °C and 65 °C.
- The ampoule (or any subsequent container) should always be clearly marked as containing radioactive material.
- If the ampoule is transported, it should be packed, marked, labeled, and shipped in accordance with the applicable national, international, and carrier regulations.
- The solution in the ampoule is a dangerous good (hazardous material) because of both the radioactivity and the strong base or acid.
- The ampoule should be opened only by persons qualified to handle both radioactive material and alkaline and/or acidic solutions.
- Appropriate shielding and/or distance should be used to minimize personnel exposure. Refer to MSDS for further information.