Contents

Organic Quality Control

Effective Date: 07/2008
Point of Contact: Quality Engineer for Regulatory Programs

Organic preparative techniques and organic analytical techniques are described below.

Organic Preparative Techniques

Preparative techniques are those operations used to prepare a sample for analysis. Preparative techniques may include digestion, dissolution, extraction, and/or leaching of a sample material. Separation and/or isolation techniques may also be considered preparative if performed to facilitate the analysis. Simple dilution is not considered a preparative technique. The Analytical Requirements for Volatile, Semivolatile, and Gas Chromatrography Quality Control exhibit provides the frequency and acceptance criteria requirements for organic preparative quality control (QC). Selection of preparative technique should be based upon client data quality requirements; however, CLP criteria will routinely be applied when matrix and compound list warrant. Clients requiring SW-846 or other specifications must clearly identify their expectations in related work-authorizing documents.

Batch

A batch is a group of samples, of similar matrix type, processed through the preparative techniques at the same time. For each batch, a set of preparative QC shall be processed. A batch shall not exceed 20 samples, excluding the preparative QC samples (e.g., PB, LCS, BS, MS, duplicate). If the client does not specify project-specific QC, the laboratory may combine up to 20 samples of similar matrix type for preparation with only one set of preparative QC. In the case of process testing or unique client requirements, QC elements such as a sample duplicate (or MSD) and MS may be performed for every 20 client-specific samples received. However, the PB and LCS or BS requirement would apply to each batch of samples prepared at one time. Unique client requirements shall be documented and agreed upon by the project and the client before work begins.

Preparation Blank

The sample PB is used to monitor contamination resulting from the sample preparation process. The PB is generally distilled or deionized water, which is subjected to the same processing as the samples, including all reagent additions. The PB volume or weight shall be approximately equal to the sample volume or weight being processed. In certain cases (e.g., semivolatile analysis of soils), addition of even a small quantity of distilled or deionized water is not recommended. In such cases, only the solvents or reagents used to treat the solid material should be added to the blank.

A matrix more closely related to the actual samples processed may be used provided the matrix is free of contamination from analytes of interest. Interferences produced by the blank matrix should be similar to that of the sample. PB acceptability shall be demonstrated by the concentration of the target analytes in the blank meeting one of the following requirements

Additionally, for organic analysis, the concentration of the following analytes shall be less than five times the EQL:

For TC/TOC/TIC analysis on intact material, the instrument blank also serves as the preparation blank. In this case, however, the blank may be subtracted from all sample results prior to reporting.

Laboratory Control Sample or Blank Spike

The LCS or BS is used to monitor the effectiveness of the sample preparation process. A LCS is a material similar in nature to the sample being processed, containing the analyte(s) of interest (e.g., standard reference material). The BS is distilled or deionized water spiked with the analyte(s) of interest. A BS is used when an appropriate LCS is unavailable. In the case of organic compounds, a typical BS may be considered the PB that is spiked with surrogate compounds.

BS control is demonstrated by target analyte recoveries within administrative limits of 70%, 130% or, within laboratory statistical control limits (when sufficient data are available to establish such limits).

LCS acceptability is demonstrated by target analytes being within established control or tolerance limits. Control limits are either provided by the vendor or statistically determined by multiple analyses over time. For the LCS, the vendor-supplied precision may affect the tolerance limits applied to the analyte.

For GC and GC/MS, the blank, spiked with surrogates, meets the BS/LCS requirement. For TC/TOC/TIC analysis on intact samples, the standard (CCV) also serves as the BS/LCS. There is no current capability to reliably perform a BS/LCS on water leach preparations for TC/TOC/TIC. When such capability becomes available, it shall be incorporated into relevant procedures.

Matrix Spike

The MS is used to monitor method performance in a specific matrix. A MS is a sample that has been spiked with the analyte(s) of interest and processed similarly to the original sample. If the sample concentration is unknown, spiking is typically performed at a level that equals one of the following:

If the sample concentration is known, the spiking should be performed at a level equivalent to that of the sample. If the concentration of the analyte in the original intact sample is greater than 0.1%, no MS is required unless specifically requested. Sample concentrations exceeding four times the spike concentration render recovery data meaningless for assessing data useability.

MS control is demonstrated when target analytes are within established control limits. Control limits are established by one of the following: 1) regulatory requirement, 2) the client via data quality requirements, or 3) laboratory performance.

Acceptance criteria for organic MSs are identified in the current CLP SOW. For compounds of interest not covered by SW-846 or the CLP, the laboratory shall establish spike compound and acceptable recovery criteria.

There is no current capability to reliably perform a MS on water leach preparations for TC/TOC/TIC. When such capability becomes available, it shall be incorporated into relevant procedures.

Sample Duplicate or Matrix Spike Duplicate

Duplicates are used to assess the precision of the preparation process. Duplicates are two aliquots of the same sample that are taken through the entire sample preparation and analytical process. MSD are two spiked aliquots of the same sample that are taken through the entire sample preparation and analytical process. Precision is estimated by calculating the RPD. To the degree possible, the project and client should agree upon the use of sample duplicates versus MSD before starting work.

Organic analyses use a MS and MSD to determine precision because the analyte(s) of interest may not be detected. In this case, precision is determined from the analytes spiked into the MS and the MSD.

Organic MS and matrix spike duplicate RPD criteria control is demonstrated by target analytes being within established control limits. Control limits are established as follows:

The limits shown in the current CLP SOW are to be used except when the compounds of interest are not covered by SW-846 or the CLP. For these compounds, the laboratory shall establish acceptable precision criteria.

Surrogate

A surrogate is a compound or analyte that is added to all samples during preparation. Each method that uses surrogates shall specify instructions for surrogate introduction and use. Surrogate recoveries are reported as measured (i.e., no sample recovery corrections are performed based on surrogate recovery). Most, if not all, organic techniques employ surrogates. The surrogates are also added to all standards and QC samples.

Organic Analytical Techniques

Analytical techniques are considered those operations which permit the measurement of a parameter of interest. Analysis can be considered the measurement of some property for which there is an instrument response that can be related to the concentration or amount of the substance of interest in a sample or in some material prepared from the sample. The QC requirements presented below are designed to verify and document proper instrument operation and to give the analyst information regarding the precision, accuracy, and sensitivity of the analytical process. The following exhibits provide frequency and acceptance criteria requirements for analytical QC:

Selection of analytical technique should be based upon the client data quality requirements. However, it should be noted that the CLP criteria will typically be applied when compound list warrants, unless otherwise requested. Clients requiring SW-846 or other criteria must clearly identify their expectations in associated work-authorizing documents.

Analytical Run or Sequence

For organic analyses by GC/MS, the run begins with the instrument tune and ends based on analytical clock expiration. For GC and carbon analysis, the run end is based on continuing calibration performance. The order in which samples and QC are analyzed shall be traceable to the analytical sequence.

Instrument Tune

An instrument tune is performed prior to initiating any analytical data collection activities involving samples, blanks, or standards by GC/MS. The tune is used to assure correct mass calibration, mass resolution, and mass transmission. The instrument tune is used to establish that a given GC/MS system meets instrument performance criteria. Tune performance criteria are either specified by the manufacturer, regulatory method or a combination of the two. Most regulatory methods specify the use of bromofluorobenzene (BFB) for volatile analysis by GC/MS and decafluorotriphenylphosphine for semivolatile analysis by GC/MS. The tune criteria specified in the most recent CLP SOW are followed unless otherwise requested. The instrument tune is required once every 12-hour analytical period and must meet the specified performance criteria (i.e., regulatory and/or manufacturer) before any samples can be analyzed. All standards, blanks, samples, and QC shall be run under the conditions used to tune the instrument.

ICV

The ICV is a standard used to confirm the acceptability of the calibration and the standards used to prepare the calibration. Acceptable performance of the ICV demonstrates that both the standards used and the instrument are functioning properly. The ICV is prepared from a source other than that used to prepare the calibration standards. Analytical measurement systems that are calibrated frequently and for which calibration standards are routinely prepared normally follow calibration with an ICV. Analytical measurement systems for which calibration applies over an extended period of time (i.e., months for some GC/MS methods) normally use the ICV only at the time of calibration. Subsequent, routine performance checks are made using the equivalent of a CCV.

Failure of the ICV indicates instrument and/or standard problems that shall be evaluated and corrected before any samples are processed for the analytes of interest.

Continuing Calibration Verification

The CCV is used to monitor instrument stability over time. The CCV may be prepared from any reliable source. Organic analysis by GC/MS is limited by analytical run time. Each run is defined by a 12-hour clock that cannot be exceeded. Each run starts with a CCV (after tuning). The analyst shall use internal standard and surrogate performance to ensure that the sample run ended in control. Corrective action, such as reanalysis of all samples, shall be taken for runs demonstrating unacceptable internal standard performance.

Analytical runs for organic analysis such as GC typically can extend anywhere from several hours to several days. Regular CCV checks are required throughout the runs duration (approximately every 12 hours for CLP analyses). Total organic carbon (TOC), total inorganic carbon (TIC), and total carbon (TC) measurements should also include CCV checks every 15 samples.

Initial and Continuing Calibration Blanks

ICBs and CCBs monitor contamination and instrument drift. The ICBs and CCBs are a reagent blank, prepared similarly to the standards but not subjected to preliminary sample preparation except for techniques in which the preparation is an integral part of the analysis. In these cases, the PB can be considered the equivalent of the ICB or CCB. The generally accepted criteria for ICBs and CCBs are that they are below the EQL for each analyte tested. When an analyte exceeds these criteria, the analysis shall be investigated for potential impact. Samples with concentrations or activities exceeding the blank contamination level by a factor of 20 or more can normally be reported unless client requirements dictate otherwise. In all other cases, all samples analyzed since the last acceptable ICB or CCB shall be reanalyzed for the specific analyte failure.

In the case of organic analysis by GC/MS, the ICB or CCB is the equivalent of the PB. The PB is run after the CCV standard. Periodic calibration blanks are not performed. In the case of organic analysis by GC, periodic blanks are recommended.

Internal Standards

Selecting appropriate internal standards shall be method- and compound-list specific because all results are normalized based on internal standard performance. Laboratory procedures shall specify acceptance criteria. Internal standards are used in organic GC/MS analysis, and they may be appropriate to other types of organic analysis. Generally, area counts falling <50% or >200% of original area counts in the continuing calibration standard are considered unacceptable.

Low-Level Standard

The LLS is used to monitor instrument performance in the region at or just above the EQL. When the LLS concentration is included in the instrument calibration, a separate LLS is not required. A LLS is not required for TOC, TIC, and TC.

Tentatively Identified Compounds

A project/program may specify criteria for determination of tentatively identified compounds (TICs). The following criteria are suggested for consideration when making a project/program specification or may be used in lieu of such specifications:

A TIC compound may be upgraded to a positively identified compound (PIC). This is achieved by obtaining the compound, analyzing it under same conditions as the initial identification, and matching retention time and mass spectrum. This may be done at the customer's request if they deem it necessary for the program. It is recommended that only PICs and not TICs be added to target analyte lists.