Mercury Research Laboratory

How to Collect a Sample

Sample integrity must be maintained throughout the sampling process, from field collection to delivery of samples to the laboratory. Contamination can occur from dust, particle matter, rain, and primary or secondary contact with contaminated surfaces (including skin, hair, clothing, or human breath). Sample contamination can be minimized through strict compliance with our lab guidelines below.

Laboratory staff will instruct and assist field sampling personnel in the use of ultra-clean trace-metal collection techniques. These techniques include, for example, the use of laboratory-supplied sampling equipment, gloves, and plastic bags to prevent sample contact with unclean surfaces. Under hostile sampling conditions, sample preservation is delayed until exposure of the sample can be minimized. Prior to shipment to the laboratory for analysis, samples are stored in a cool place away from sunlight to limit the effect of photo degradation or biological activity and to assure sample integrity. 


What analysis method do you need? See the Analysis Methods page for a cross-reference of lab analysis codes, detection limits, NWIS codes, and reference publications for the method. 


See an example of a properly completed Analytical Service Request Form to help ensure accurate paperwork for your project. 


Collection Steps: 

  1. Make sure you have read the USGS National Field Manual (NFM) guidance on water sampling. 
  2. Review and select the analysis types required for your project. A complete list of Analysis Types is listed on the back of the  Analytical Service Request form . Standard methods that cross-reference to our analysis type codes can be found on the Analysis Methods page. 
  3. Obtain sampling equipment from the Mercury Lab. This request must be received two (2) weeks prior to the expected sample collection date. You must identify the need for additional equipment to collect duplicates and blanks, including field blank water, when requesting equipment. 
  4. Receive the sampling equipment. Field personnel must verify that all sampling equipment received from the Mercury Lab is intact with no indications of shipping damage. 
  5. Collect your samples. Upon collection of a sample, the field sampling personnel places the second bar code (stored in outer container bag) on an  Analytical Service Request form in the space adjacent to the type of mercury collection. If the sample was acidified in the field, the unique identification number of the bottle used for acid preservation must be recorded on the Request for Analysis form. 
  6. Sample filtration. If filtering samples, follow the Filtration Procedure using mercury-clean equipment. 
  7. Storage. Prior to shipment to the laboratory for analysis, store samples in a cool place away from sunlight to limit the effect of photo degradation or biological activity and to ensure sample integrity. 
  8. Prepare the shipping coolers. For each cooler shipped to the lab, complete a Shipping Inventory form. Sampling personnel should verify that all items listed on the inventory form are included in the container of samples to be shipped and will note any information regarding known problems that may affect sample integrity. The completed Cooler Inventory form and Request for Analysis forms are then signed and dated by the person responsible for shipping the container of samples to the Mercury Lab. Send the original of each form and seal them in a zip-type bag to avoid water damage. 
  9. Ship the samples. Inform the Mercury Research Laboratory that a container was shipped and the method of shipment. All containers must be shipped "next day priority" unless other arrangements are made with laboratory personnel. The sampling personnel are responsible for tracking the container until receipt by laboratory personnel. 
  10. Follow-up. At any time after shipping, if you determine that the site name, station ID, or other information on the Request for Analysis form is incorrect, contact the Lab immediately at


Sarah E Janssen

Research Chemist
Upper Midwest Water Science Center
Phone: 608-821-3976