Are compunds used for SIP studies radioactive?

No.  For stable isotope probing (SIP), Bio-Traps are baited with specially synthesized compounds containing a stable carbon isotope (carbon-13) not the radioactive isotope (carbon-14) commonly used for radiocarbon dating in the fields of archeology and geology.

Can Microbial Insights receive international samples?

Yes.  Microbial Insights has an international soil permit and has received samples without problem from many different countries. Please see international shipment for additional information.

Can Microbial Insights receive samples on Saturday?

Microbial Insights is now open on Saturdays.  However, coolers should be shipped to a FedEx drop location and held where an MI representative will collect them.  It is important to ship to the Saturday delivery address and follow all procedures as indicated under the sample shipment section.  Please note that due to the short hold time associated with RNA and culture, it is recommended that these samples NOT be shipped for Saturday delivery.

Do I need to add a preservative to my samples?

For most analyses, the only preservative that is required is that the samples are shipped on ice at 4c for next day delivery.

Samples collected for CENSUS-expression (RNA) must be collected using the bio-flo sampling approach or bio-trap samplers. Following collection, each bio-flo sample MUST BE preserved using a special RNA preservative which is shipped along with your other sampling supplies. Please see the bio-flo sampling protocol for more information about this approach.

How long can I store Bio-Trap samplers prior to deployment?

Bio-Trap Samplers need to remain sealed and refrigerated (not frozen) until the can be installed in the field.  As long as they are maintained in this condition, they will be fine for use.

Should a monitoring well be purged prior to Bio-Trap deployment?

If the monitoring well has not been purged recently, it may be necessary prior to deployment.  MI recommends that three well volumes be removed to ensure contact with formation water and reduce well bore effects.

What are the hold times?

The hold times for each analysis are listed below:


PLFA24-48 hours
CENSUS24-48 hours
CENSUS-Expression (RNA)24 hours
Heterotrophic Plate Counts24-48 hours
ORm7-10 days
Acidity Testing7-10 days
DGGE24-48 hours
Most Probable Numbers (MPNs)24-48 hours

What states have SIP Bio-Trap studies been performed in?

Currently SIP Bio-Trap studies have been performed in the following states:  Arkansas, California, Colorado, Florida, Georgia, New York, New Jersey, North Carolina, Maryland,  Massachusetts, Missouri, Minnesota, Nebraska, Oklahoma, Pennsylvania, South Carolina, Tennessee, Texas, and Virginia.

Outside the US these studies have been performed in Canada, Israel, Thailand, and United Kingdom.

Will the use of a SIP Bio-Trap Samplers in a well effect CSIA results?

YES, there is potential for the use of these enriched 13C tracer compunds to effect the results obtained from CSIA analyis for the same compound.  MI advices that if you are interested in performing CSIA please collect these samples prior to the deployment of SIP Bio-Trap samplers.

In order to minimize the effect these samplers had on the monitoring well, MI recommends purging three well volumes from the test well during the retrevial of the SIP Bio-Trap samplers.