The Reston Chlorofluorocarbon Laboratory

Dissolved Gases N2 / Ar Frequently Asked Questions

  1. What gas analyses are available?
    Two services are available: dissolved helium-4 by itself, and a package including dissolved N2, Ar, CH4, O2, CO2
  2. What are the reporting levels for the analysis
  3. Why collect samples for N2, Ar, CH4, O2, and CO2?
  4. Why do I need to collect dissolved gases in duplicate?
    All dissolved gas samples are normally analyzed in duplicate.  This provides the user with some QA/QC information.
  5. Do I have to pay for duplicate samples?
    No.
  6. Can I pre-pay for analyses?
    Yes.
  7. How do I collect samples for dissolved gases?
  8. What Standards are used to analyze samples for dissolved gases?
  9. How long can I keep the bottles before shipping?
    Samples should be shipped within one week of collection.
  10. How should the samples be stored before shipping?
    Store under refrigeration (approximately 4 ºC; Caution: Do not freeze the sample) or preferably, on ice, until shipping.  This will minimize expansion of the water on warming which could cause the stopper to come out of the bottle.  This will also minimize microbial activity that can affect dissolved oxygen, carbon dioxide, and even nitrogen and methane in the sample.
  11. Can I put labels on the sample bottle?
    No.  The bottles have been weighed in the lab before shipping to you.  The label would change the weight of the bottle.  You can put the label on the sleeve that holds the bottle.
  12. Can I change stoppers used on the bottle?
    No.  The stopper has been weighed in the lab and belongs with the bottle it came with.
  13. What do I do if there is a bubble in the bottle?
    If the bubble was introduced during collection, empty the sample and repeat the collection. 
  14. What if a bubble forms in the bottle during shipping or storage?
    This is normally not a problem.
  15. I’m having trouble getting the stopper to go into the bottle.  How far do I have to get it in the bottle?
    At least half way.  Do not add any lubricant to the stopper.
  16. How do I dispose of the used needles?
    You May return needles to the Dissolved Gas Lab, or dispose of them in accordance with OSHA regulations.  You may place the used needles in a bottle and return that bottle with your samples.

Dissolved Helium Frequently Asked Questions

  1. Why do I need to sample dissolved Helium in ground water?
  2. Why do I need to collect dissolved Helium in duplicate?
    The duplicate sample is a backup in case of analytical problems in the lab, and also some samples are analyzed in duplicate to provide the user with some QA/QC information.
  3. Do I have to pay for duplicate samples?
    No.
  4. Can I pre-pay for analyses?
    Yes.
  5. How do I collect dissolved helium samples?
  6. What Standards are used to analyze dissolved Helium?
    Two standards are used.  One is air and the other is nitrogen containing 35 ppmv of helium.
  7. How long can I keep the bottles before shipping?
    Samples should be shipped within one week of collection.
  8. How should the samples be stored before shipping?
    Store under refrigeration (approximately 4 ºC; Caution: Do not freeze the sample) or preferably, on ice, until shipping.  This will minimize expansion of the water on warming which could cause the stopper to come out of the bottle.
  9. Can I put labels on the sample bottle?
    No.  The bottles have been weighed in the lab before shipping to you.  The label would change the weight of the bottle.  You can put the label on the sleeve that holds the bottle.
  10. Can I change stoppers used on the bottle?
    No.  The stopper has been weighed in the lab and belongs with the bottle it came with.
  11. What do I do if there is a bubble in the bottle?
    If the bubble was introduced during collection, empty the sample and repeat the collection.
  12. What if a bubble forms in the bottle during shipping or storage?
    This is normally not a problem.
  13. I’m having trouble getting the stopper to go into the bottle.  How far do I have to get it in the bottle?
    At least half way.  Do not add any lubricant to the stopper.
  14. How do I dispose of the used needles?
    You May return needles to the lab, or dispose of them in accordance with OSHA regulations.  You may place the used needles in a bottle and return that bottle with your samples.