Environmental professionals understand that sample integrity leads to good quality data. Care is needed when handling samples, especially as outdoor temperatures rise. The following tech tips can help!

Thermal Preservation Tips

Most test methods require a thermal preservation of ≤ 6° C of samples to meet compliance requirements. It can be particularly challenging during the summer months to keep environmental samples cold.  

  • Place samples in an insulated cooler filled with wet ice as they are collected out in the field.

DO NOT USE ICE PACKS – they will not keep samples adequately cool.

  • Refrigerate samples (in a dedicated refrigerator) until they are transported to the laboratory.

Reminder – The refrigerator in EAI’s vestibule is open 24 hours a day/7 days a week.

  • Place samples in an insulated cooler filled with wet ice when transporting to the laboratory. EAI couriers travel with coolers filled with ice to keep customer samples cool.


  • Micro/bacteria samples should be placed in a zip lock bag prior to placing in sample coolers filled with ice to reduce potential contamination.
  • It is not necessary to keep a trip blank cool until samples are collected.
  • Samples kept on ice, collected earlier the same day the lab receives them and still exceed ≥ 6° C upon receipt, are considered in compliance.

Sample Collection Tips

Higher temperatures can also impact sample collection efforts. Volatile Organic Compound (VOC) samples, for example, have a higher tendency to have air bubbles in the vial when collected in the warmer weather.

  • Fill all containers to the top with sample.
  • Invert VOC vials to detect if any air bubbles are present. If present, add more water.

Find complete VOC sampling instructions here.

  • If you suspect the sample matrices could react with the preservation and cause the sample to effervesce, please let us know and we’ll supply you with unpreserved containers.
  • Check that sample IDs, dates and times on the container labels match what is noted on your COC.


  • Limited sample volume? Call us; we may be able to analyze the volume of sample you are able to collect depending on the test(s) needed.

Container Storage Tips

Where sample containers are stored and the length of time they are stored, can impact sample integrity as well.

  • Store all containers in a cool, dry place away from dust, dirt, fumes, grime and chemicals including gasoline.
  • Do not use HCl preserved VOC vials, if they are older than 6 months.
  • Do not use methanol preserved VOC vials beyond the expiration date on the label.

If you have questions or need environmental samples analyzed, let EAI assist you. To learn more or place an order please call 1-800-287-0525 or email Customer Service today.