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Analysis for 1,2,3-Trichloropropane

Last Update: November 1, 2007

(This page is archived for historic value, and is no longer being updated. For more information, CDPH's 1,2,3-TCP webpage.)


1,2,3-Trichloropropane (1,2,3-TCP) was an Unregulated Chemical Requiring Monitoring, as set forth in a regulation that required monitoring from January 2001 through December 2003, and was repealed in October 2007. 

Information about analysis of 1,2,3-TCP that was provided for that monitoring requirement is provided below.

The notification level for 1,2,3-TCP is 0.000005 mg/L (5 ng/L), the same level used as the detection limit for purposes of reporting (DLR).

Methods for 1,2,3-TCP Analysis

Due to the extremely low DLR, USEPA methods 502.2, and 524.2 are not applicable for determining this compound in drinking water.   Consequently, the Sanitation and Radiation Laboratories (SRL) have developed two GC/MS methods (Purge and Trap GC/MS and Liquid-Liquid Extraction GC/MS) that are capable of 1,2,3-TCP quantification at the DLR.  

Laboratories performing an analysis for 1,2,3-TCP may use one of the GC/MS methods above. Alternatively, EPA methods 504.1 or 551.1 may also be used if the laboratory can demonstrate that the method is capable of achieving the DLR of 0.000005 mg/L without method modification.

A laboratory using EPA method 504.1 or 551.1 will be required to do the following:

  • Demonstrate that it can achieve the DLR,
  • Demonstrate that the blank is not contaminated, and
  • Confirm a positive detection that is at or above the DLR either by a second column analysis, or by one of the GC/MS methods above. This confirmation will be required only for the initial characterization of a water source. Confirmation will not be required on subsequent analyses of the same water source.

NOTE: A 1,2,3-TCP finding in a sample that has high TDS or volatile content, or otherwise precludes unambiguous confirmation, should be confirmed with one of the GC/MS methods above.

Certification Requirements

To perform the analysis for 1,2,3-TCP in drinking water, a laboratory must seek interim certification from the Environmental Laboratory Accreditation Program (ELAP) by doing the following.  A laboratory must:

  • Send in an ELAP application for certification,
  • Conduct an initial demonstration of performance/capabilities,
  • Provide a validation data package,
  • Have a written SOP to demonstrate laboratory capability,
  • Successfully analyze a DHS-provided performance evaluation (PE) sample. Only one PE testing round (see Note) will be scheduled by DHS for 2003. The PE samples will be distributed by SRL, including instructions for the study.

    Note:  Two PE testing rounds were originally scheduled for 2003. However, to expedite the certification process, the first PE samples were distributed by SRL at the end of October 2002 to the laboratories that responded to ELAP’s September 2002 email and fax notices regarding the PE study. Therefore, only one testing round will be scheduled for 2003. This final PE testing round will be conducted in early March 2003. Unless further notice is given, certification for the analysis of low-level 1,2,3-trichloropropane in drinking water will be required only for the duration of 2003. Laboratories that passed the first PE testing round and were given interim certification by ELAP do not need to participate in the final testing round, unless seeking certification for an additional method.

Upon passing a laboratory inspection by ELAP (to be conducted at the time of the regular site inspection), the laboratory will be granted full certification. Interim certification may be granted based on the above and the laboratory inspection will be conducted at the time of the regular site visit. For further details refer to the ELAP web page.

If you have general certification questions, please contact ELAP.

Last modified on: 10/22/2013 8:05 AM