Frequent Questions

For SW-846 Method 1311, what are the holding times for the samples before leaching, the leachates before extraction, and the extracts before analysis?

What are the holding times for the samples before leaching, the leachates before extraction, and the extracts before analysis?

 

A table in Sec. 8.5 of Method 1311 indicates:

Sample must undergo TCLP within the following time periods:

 

SAMPLE MAXIMUM HOLDING TIMES [DAYS]

   

From:

Field

Collection:

 

To:

TCLP

Extraction

 

From:

TCLP

Extraction

 

To:

Preparative

Extraction

 

From:

Preparative

Extraction

 

To:

Determ.

Analysis

 

Total

Elapsed

Time

Volatiles  14 NA 14 28
Semi-volatiles  14 7 40  61
Mercury  28 NA 28 56
Metals, except mercury

180

NA

180

360

NA: Not Applicable

For the leachate that will be analyzed for organics (including volatiles, semivolatiles, and the herbicides), you have 14 days from the collection of the original sample until you have to start the leaching (extraction).  For the metals, you have 180 days from collection until leaching, except for mercury, where leaching must start within 28 days.

The herbicides are grouped with the "semivolatiles" in Sec. 8.5 of the method, since both types of analytes are extracted with an organic solvent.  The extractions of the semivolatiles and herbicides from the leachate must start within 7 days of the completion of the leaching procedure.

The determinative analyses for the semivolatiles and herbicides must be completed within 40 days of the completion of the solvent extractions.  The determinative analyses for the volatiles must be completed within 14 days of the completion of the leaching procedure.

The determinative analyses for the metals must be completed within 180 days of the completion of the leaching procedure, except for mercury, where analyses must be completed within 28 days of the completion of the leaching procedure.

Other Category: Holding Time & Preservation

 

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