QC Solution Descriptions

The QC tab will only be displayed if Enable QC is selected in the Configuration page. The tests are selected from the QC page. The equations provided are examples and should be updated to meet your standard operating procedures.

QC Solution Categories and Types

Select one of the QC solutions from the QC Type drop-down menu on the QC tab in the worksheet. The QC solution types can split into five types of QC solutions categories. Each of the QC solution categories has a corresponding table that allows the user to insert the QC pass criteria.

• Check Standards
  • Continuing Calibration Verification (CCV) - A type of QC Standard, a CCV is a solution of known concentration used to verify the accuracy of a calibration. The CCV should be performed at regular intervals during the analysis.
  • Initial Calibration Verification (ICV) - A type of QC Standard, an ICV is a solution of known concentration used to verify the accuracy of a calibration. The ICV should be performed immediately after every full calibration.
  • Interference Check Solution A (ICSA) - Standard A contains interfering element(s) in known concentrations.
  • Interference Check Solution AB (ICSAB) - Standard AB contains interfering element(s) in Interference Check Solution A in the same concentration plus a known concentration of analyte element(s).
  • Laboratory Control Sample (LCS) - An independent check sample similar to the QC Standard concept. The true composition is known and the % Recovery can be calculated and tested against the specified upper and lower recovery limits.
  • Contract Required Quantitation Limit Standard (CRS) - The CRS is a check standard of known concentration (at the CRQL) used to verify the linearity of a calibration near the CRQL. The CRS is prepared in the same matrix as the calibration standards and should be analyzed at the following intervals:
    • the beginning (immediately after the ICV/ICB but before the ICSA/ICSAB)
    • the end of each sample analysis run
    • at regular intervals during the run

    It is provided for backwards compatibility with ILMO5.x and earlier.

• Check Blanks 
  • Continuing Calibration Blank (CCB) - A QC Blank analyzed with a Continuing Calibration Verification.
  • Initial Calibration Blank (ICB) - A QC Blank analyzed with an Initial Calibration Verification.
  • Preparation Blank (PBLK) - The Preparation Blank is a volume of reagent water (or a clean wipe for wipe analyses) that is processed through the sample preparation procedures. The Preparation Blank result therefore gives an indication of any contamination picked up during the sample preparation process.
• Paired Samples
  • Duplicate (DUP) - A Duplicate test involves taking two aliquots from a single sample and processing each through the same sample preparation procedure, in order to determine the homogeneity of a sample and precision of the method. The duplicate will always follow the original sample. The Duplicate check consists of a comparison of the results of the two samples.
  • Serial Dilution (SER) - The Serial Dilution check consists of a comparison of the results for a sample and a diluted aliquot of the original sample. The pair of samples must be placed consecutively in the sequence.
• Spikes
  • Matrix Spike (MSPK) - A Matrix Spike is a pre-digest spike. A duplicate aliquot of a sample is spiked with known quantities of specific compounds and subjected to the entire analytical procedure, in order to indicate the appropriateness of the method for the sample matrix by measuring the spiked analyte recovery. If the analyte recovery does not meet the acceptance criteria then a QC Spike may need to be performed.
  • Matrix Spike Duplicate (MSD) - A duplicate preparation of the Matrix Spike. This QC test combines two separate criteria: the spiked analyte recovery (as for Matrix Spike); and a duplicate comparison with the first Matrix Spike solution (as for Duplicate). Both sets of criteria must satisfied for this test to pass.
  • QC Spike (QCSPK) - A QC Spike is a Post-digest spike which is used to determine whether any significant matrix interferences are present. It is a sample that is equivalent to the sample preceding it in the sequence, except that it has been ‘spiked’ with a known amount of analyte standard solution. A QC Spike usually follows a Matrix Spike.
• Sample Aggregate (SSUM) - A standalone test that calculates aggregate statistics across groups of samples, so that summarized data (average, SD, %RSD, min, max) can be reported instead of individual measurement results.
• Rinse - A standalone test that will report the calculated concentration of the rinse solution.
• Expanded QC
  • All Sample QC - a test that can be run on all samples or sample types to ensure those samples meet the criteria defined in the equation. This is only present when Expanded QC is enabled in ICP Expert Pro.
  • LSpike - included as a test to help meet specific USP232/233 method validation requirements. This is only present when Expanded QC is enabled in ICP Expert Pro.

Only SSUM and Rinse are available when Standard Bracketing is selected. All other QC tests are not available.

Check Standards Categories

Laboratory Control Sample, Continuing Calibration Verification, Interference Check Solution A, Interference Check Solution AB, Contract Required Quantitation Limit Standard and Initial Calibration Verification are all check standards type solutions and share the same categories in the table that appears when one of these solution types is selected.

The following Check Standard tests are available:

• Continuing Calibration Verification
• Initial Calibration Verification
• Interference Check Solutions
• Laboratory Control Sample
• Contract Required Quantitation Limit Standard

The Check Standard tests form part of the suite of QC Tests available on ICP Expert.

Continuing Calibration Verification (CCV)

If you enable the CCV test, the QC grid will display the following by default:

Check Box	Select which elements from the analysis are going to be governed by the QC pass criteria. All elements are automatically selected when the test is enabled. You can select any you want, but if you have not selected an element, it will not be QC tested.
Defined Concentration	Enter the known concentration of the CCV. The units used are the same as those defined in the Concentrations table on the Standards page.
Lower Limit	This is the lower acceptable limit for the QC read back listed as a percentage of the actual concentration entered in the defined concentration cell. For example, if the Lower Limit is set to 90% and your defined concentration is 1.0, then a read back greater than or equal to 0.9 (while still satisfying the Upper Limit requirements) would result in a QC test Pass.
Upper Limit	This is the upper acceptable limit for the QC read back listed as a percentage of the actual concentration entered in the defined concentration cell. For example, if the Upper Limit is set to 110% and your defined concentration is 1.0, then a read back less than or equal to 1.1, (while still satisfying the Lower Limit requirements) would result in a QC test Pass.

The percentage recovery is calculated for the CCV as follows:

(MeasuredConc / DefinedConc) * 100

where:

MeasuredConc is the measured concentration DefinedConc is the CCV defined concentration

The selected error action is applied when the found % recovery is greater than the high limit or less than the low limit. The default failure flag is Q.

Continuing Calibration Verification QC tests can be included in an analysis by selecting them from the Sequence page. The action taken will depend upon the Error Action selection made on the QC page.

Initial Calibration Verification (ICV)

A type of QC Standard, an ICV is a solution of known concentration used to verify the accuracy of a calibration. The ICV should be performed immediately after every full calibration.

If you enable the ICV test, the QC grid will display the following by default:

Check Box	Select which elements from the analysis are going to be governed by the QC pass criteria. All elements are automatically selected when the test is enabled. You can select any you want, but if you have not selected an element, it will not be QC tested.
Defined Concentration	Enter the known concentration of the ICV. The units used are the same as those defined in the Concentrations table on the Standards page.
Lower Limit	This is the lower acceptable limit for the QC read back listed as a percentage of the actual concentration entered in the defined concentration cell. For example, if the Lower Limit is set to 90% and your defined concentration is 1.0, then a read back greater than or equal to 0.9 (while still satisfying the Upper Limit requirements) would result in a QC test Pass.
Upper Limit	This is the upper acceptable limit for the QC read back listed as a percentage of the actual concentration entered in the defined concentration cell. For example, if the Upper Limit is set to 110% and your defined concentration is 1.0, then a read back less than or equal to 1.1, (while still satisfying the Lower Limit requirements) would result in a QC test Pass.

The percentage recovery is calculated for the ICV as follows:

(MeasuredConc / DefinedConc) * 100

where:

MeasuredConc is the measured concentration DefinedConc is the ICV defined concentration

The selected error action is applied when the found % recovery is greater than the high limit or less than the low limit.  The default failure flag is Q.

Initial Calibration Verifications can be included in an analysis by selecting them from the Sequence page. The action taken will depend upon the Error Action selection made on the QC page.

Interference Check Solutions

An Interference check (ICS) is used to verify that any interferent corrections performed are valid. The check requires that ICSA and ICSAB solutions are placed consecutively in the sequence.

Interference Check Solutions are only required if you are performing Inter-Element Corrections. Click here for information on the Inter-element Correction page.

Interference Check Solution A (ICSA)

Standard A contains the interferent element(s) in known concentration(s).

Interference Check Solution A does not use the same Limits table as the other standards. Instead, it uses the CRQL value in the 'Pass test' equation. Click here for more information about CRQL values.

If you enable the ICSA test, the table will display the following by default:

Check Box	Select this check box to include an element in the QC test. All elements are automatically selected when the test is enabled.
Defined Concentration	Enter the concentration of the ICSA. The units used are the same as those defined in the IEC or Standards page.
Lower Limit	This is the lower acceptable limit for the QC read back listed as a percentage of the actual concentration entered in the defined concentration cell. For example, if the Lower Limit is set to 90% and your defined concentration is 1.0, then a read back greater than or equal to 0.9 (while still satisfying the Upper Limit requirements) would result in a QC test Pass.
Upper Limit	This is the upper acceptable limit for the QC read back listed as a percentage of the actual concentration entered in the defined concentration cell. For example, if the Upper Limit is set to 110% and your defined concentration is 1.0, then a read back less than or equal to 1.1, (while still satisfying the Lower Limit requirements) would result in a QC test Pass.

The report value is calculated for the ICSA test is as follows:

(MeasuredConc/DefinedConc * 100) 

where:

MeasuredConc is the measured concentration DefinedConc is the ICSA defined concentration

The selected error action is applied when the measured concentration is:

• Less than the defined concentration multiplied by the lower limit (as a percentage) or the defined concentration minus the CRQL (whichever is lower).

OR

• Greater than the defined concentration multiplied by the upper limit (as a percentage) or the defined concentration plus the CRQL (whichever is higher).

Define the limit for the ICSA in the Detection Limits table. MDL (or a multiple of) can be used instead of CRQL. If you use MDL for your limit, you must change the equation to reflect this.

Define the limit for the ICSA in the Detection Limits table (CRQL or MDL). 

The default failure flag for ICSA is K.

Interference Check Solutions can be included in an analysis by selecting them on the QC page. The action taken will depend upon the Error Action selection made on this page.

Interference Check Solution AB (ICSAB)

Standard AB contains the interference element(s) in Interference Check Solution A in the same concentration plus a known concentration of analyte element(s).

If you enable the ICSAB test, the QC grid will display the following by default:

Check Box	Select which elements from the analysis are going to be governed by the QC pass criteria. All elements are automatically selected when the test is enabled. You can select any you want, but if you have not selected an element, it will not be QC tested.
Defined Concentration	Enter the concentration of the ICSAB. The units used are the same as those defined in the IEC or Standards page.
Lower Limit	This is the lower acceptable limit for the QC read back listed as a percentage of the actual concentration entered in the defined concentration cell. For example, if the Lower Limit is set to 90% and your defined concentration is 1.0, then a read back greater than or equal to 0.9 (while still satisfying the Upper Limit requirements) would result in a QC test Pass.
Upper Limit	This is the upper acceptable limit for the QC read back listed as a percentage of the actual concentration entered in the defined concentration cell. For example, if the Upper Limit is set to 110% and your defined concentration is 1.0, then a read back less than or equal to 1.1, (while still satisfying the Lower Limit requirements) would result in a QC test Pass.

The report value is calculated for the ICSAB test is as follows:

(MeasuredConc/DefinedConc * 100)

where:

MeasuredConc is the measured concentration DefinedConc is the ICSAB defined concentration

Interference Check Solutions can be included in an analysis by selecting them on the QC page. The action taken will depend upon the Error Action selection made on this page.

The selected error action is applied when the measured concentration is:

• Less than the defined concentration multiplied by the lower limit (as a percentage) or the defined concentration minus the CRQL (whichever is lower).

OR

• Greater than the defined concentration multiplied by the upper limit (as a percentage) or the defined concentration plus the CRQL (whichever is higher).

Define the limit for the ICSAB in the Detection Limits table. MDL (or a multiple of) can be used instead of CRQL. If you use MDL for your limit, you must change the equation to reflect this.

The default failure flag for ICSAB is G. 

Interference Check Solutions can be included in an analysis by selecting them on the QC page. The action taken will depend upon the Error Action selection made on this page.

Laboratory Control Sample (LCS)

The Laboratory Control Sample (LCS) is an independent check sample very similar to the QC Standard concept. The composition is known and the % recovery can be calculated and tested against the specified upper and lower recovery limits.

If you enable the LCS test, the QC grid will display the following by default:

Check Box	Select which elements from the analysis are going to be governed by the QC pass criteria. All elements are automatically selected when the test is enabled. You can select any you want, but if you have not selected an element, it will not be QC tested.
Defined Concentration	Enter the known concentration of the LCS. The units used are the same as those defined in the Concentrations table on the Standards page.
Lower Limit	This is the lower acceptable limit for the QC read back listed as a percentage of the actual concentration entered in the defined concentration cell. For example, if the Lower Limit is set to 90% and your defined concentration is 1.0, then a read back greater than or equal to 0.9 (while still satisfying the Upper Limit requirements) would result in a QC test Pass.
Upper Limit	This is the upper acceptable limit for the QC read back listed as a percentage of the actual concentration entered in the defined concentration cell. For example, if the Upper Limit is set to 110% and your defined concentration is 1.0, then a read back less than or equal to 1.1, (while still satisfying the Lower Limit requirements) would result in a QC test Pass.

The US EPA requires a Laboratory Control Sample (LCS) to be analyzed for each group of samples in a Sample delivery group or for each group of samples digested, whichever is more frequent. 

The percentage recovery is calculated for the LCS as follows:

(MeasuredConc / DefinedConc) * 100

where:

MeasuredConc is the measured concentration DefinedConc is the LCS defined concentration

The selected error action is applied when the found concentration of the LCS % is greater than the high limit or less than the low limit. The default failure flag is L .

Laboratory Control Samples can be included in an analysis by selecting them from the Sequence page. The action taken will depend upon the Error Action selection made on the QC page.

Contract Required Quantitation Limit Standard (CRS)

This solution only applies to CLP ILM protocols and is obsolete for ISM protocols (although some labs may still be complying with older protocols where this was used). This solution is for compatibility with earlier ILM specifications and the term CRQL is equivalent to CRDL for ILMO4.x and earlier. It is provided for backwards compatibility with ILMO5.x and earlier.

If you enable the CRS test, the QC grid will display the following by default:

Check Box	Select this check box to include an element in the QC test. All elements are automatically selected when the test is enabled.
Defined Concentration	Enter the known concentration of the CRS. The units used are the same as those defined in the Concentrations table on the Standards page.
Lower Limit	This is the lower acceptable limit for the QC read back listed as a percentage of the actual concentration entered in the defined concentration cell. For example, if the Lower Limit is set to 90% and your defined concentration is 1.0, then a read back greater than or equal to 0.9 (while still satisfying the Upper Limit requirements) would result in a QC test Pass.
Upper Limit	This is the upper acceptable limit for the QC read back listed as a percentage of the actual concentration entered in the defined concentration cell. For example, if the Upper Limit is set to 110% and your defined concentration is 1.0, then a read back less than or equal to 1.1, (while still satisfying the Lower Limit requirements) would result in a QC test Pass.

The percentage recovery is calculated for the CRS as follows:

(MeasuredConc / DefinedConc) * 100

where:

MeasuredConc is the measured concentration DefinedConc is the CRS defined concentration

The selected error action is applied when the found concentration of the CRS % is greater than the high limit or less than the low limit. The default failure flag is R.

CRS's can be included in an analysis by selecting them from the Sequence page. The action taken will depend upon the Error Action selection made on the QC page.

Check Blanks Category

Continuing Calibration Blank, Preparation Blank, and Initial Calibration Blank are all Check Blanks type solutions and share the same categories in the table that appears when one of these solution types is selected. Check Blanks are used to periodically monitor the Calibration Zero solution which in turn monitors the contamination levels. The Check Blank must be analyzed after every Check Standard analysis.

A QC blank is used to:

• Check the validity of the analytical calibration.
• Check for possible contamination of the sample introduction system.
• Check the sample preparation procedures.

The following Check Blanks tests are available:

• Preparation Blank
• Initial and Continuing Calibration Blank

Preparation Blank (PBLK)

The Preparation Blank is a volume of distilled, de-ionized water that is processed through the sample preparation procedures. The Preparation Blank result therefore gives an indication of any contamination picked up during the sample preparation process.

If you enable the PBLK test, the QC grid will display the following:

Check Box

Select to include an element in the QC test. All elements are automatically selected when the test is enabled.

The test passes if the measured concentration is less than the CRQL.

Define the limit for the PBLK in the Detection Limits table (CRQL or MDL). If you use MDL for your limit, you must change the equation to reflect this.

The US EPA requires one PBLK to be analyzed with every sample delivery group or with each batch of samples digested, whichever is more frequent. If the absolute PBLK concentration is less than the CRQL or MDL limit, no action is required.

If any analyte concentration is above the DL, the lowest concentration of the analyte in the associated samples must be 10 times the PBLK concentration or else those samples which are less than 10 times the PBLK concentration must be re-digested and re-analyzed for that analyte.

The selected error action is applied when the found concentration of the PBLK is found to be greater than the specified limit. The default failure flag is Z.

Preparation Blanks can be included in an analysis by selecting them from the Sequence page. The action taken will depend upon the Error Action selection made on the QC page.

Initial Calibration Blanks (ICB) and Continuing Calibration Blanks (CCB)

An ICB is a check blank that is analyzed with an Initial Check Standard. A CCB is a check blank that is analyzed with a Continuing Check Standard.

The following information applies to both Initial and Continuing Calibration blanks.

If you enable an ICB or CCB test, the QC grid will display the following:

Check Box

Select this check box to include an element in the QC test. All elements are automatically selected when the test is enabled.

The test passes if the measured concentration is less than the CRQL. Define the limit for the ICB or CCB in the Detection Limits table (MDL or CRQL). If you use MDL for your limit, you must change the equation to reflect this.

If the concentration of the ICB or CCB is found to be greater than the CRQL or MDL limit, the following procedure should occur:

The requirements below can be met by setting the Error Action option in the QC page to Recalibrate and repeat.

1. Terminate the analysis and correct the problem.
2. Recalibrate and then verify the calibration (i.e., ICV/ICB).
3. Reanalyze the preceding 10 analytical samples or all samples analyzed since the last compliant calibration blank.

The selected error action is applied when the found concentration of the ICB or CCB is found to be greater than the specified limit. The default failure flag is Z.

Initial Calibration Blanks and Continuing Calibration Blanks can be included in an analysis by selecting them from the Sequence page. The action taken will depend upon the Error Action selection made on the QC page.

Paired Samples Category

Paired sample tests compare the results of a pair of samples. The Duplicate and Serial Dilution solutions are Paired Samples type solutions. These solutions are the only solutions that need to be placed immediately following the solution that it is a duplicate of. This has it's own unique table that appears when this solution type is selected.

• Duplicate
• Serial Dilution

Duplicate (DUP)

A Duplicate test involves splitting a sample into two and processing each half of the sample through the same sample preparation procedure, in order to determine the precision of the method. The duplicate will always follow the original sample.

If you enable the DUP test, the table will display the following by default:

Check Box	Select this check box to include an element in the QC test. All elements are automatically selected when the test is enabled.
Difference	Enables you to set the allowable % difference limit between the sample and its corresponding duplicate. The US EPA defines the difference for Dup tests as being 20%, and this value is the default setting for this test.

The percent difference is calculated and is then compared to the specified limit:

abs(MeasuredConc(PreviousSample) - MeasuredConc) / abs((MeasuredConc(PreviousSample) + MeasuredConc) / 2) * 100

where:

MeasuredConc(PreviousSample) is the first sample value MeasuredConc is the second sample value (duplicate)

The check is deemed to fail when the percentage difference exceeds the limit specified or the measured concentration is greater than 5 * CRQL. The default failure flag is *.

Duplicates can be included in an analysis by selecting them on the Sequence page. The action taken will depend upon the Error Action selection made on the QC page.

By default, Duplicates are counted as samples.

Serial Dilution (SER)

A serial dilution consists of a comparison of the results of a sample and another aliquot diluted by a known factor. The pair of solutions must be placed consecutively in the sequence, with the undiluted sample being followed by the diluted sample.

If you enable the SER test, the QC grid will display the following by default:

Selected	Select this check box to include an element in the QC test. All elements are automatically selected when the test is enabled.
% Difference	Enables you to set the allowable % difference limit between the two serially diluted samples. The US EPA defines the difference for SER tests as being 10%.

When performing a Serial Dilution check, ICP Expert will do the following:

1. Determine the concentration of the diluted sample.
2. Multiply it by the dilution factor, which is specified in the Sequence page.
3. Compare it to the concentration value obtained for the undiluted sample preceding it.

The percentage difference of the diluted sample to the preceding sample is calculated as follows:

abs(MeasuredConc - MeasuredConc(PreviousSample)) / MeasuredConc(PreviousSample) * 100

and is then compared to the limit specified.

The check is deemed to fail when the percentage difference exceeds the limit specified. The test is deemed to pass if the %D is < the limit or the previous sample concentration is < 50xMDL. If the sample concentration is greater than 50xMDL then the %D must be less than the limit to pass, if it is less than 50xMDL then the %D does not need to be less than the limit to pass. The default failure flag is E.

Serial dilutions can be included in an analysis by selecting them from the Sequence page. The action taken will depend upon the Error Action selection made on the QC page.

Spikes

Matrix Spike, Matrix Spike Duplicate and QC Spike are Spike solutions that share the same categories in the table that appears when one of these solution types is selected.

The following Spike tests are available:

• QC Spike
• Matrix Spike
• Matrix Spike Duplicate

QC Spike (QCSPK)

A QC Spike is a Post-digest spike which is used to determine whether any significant interferences are present, thereby requiring the use of Standard Additions.
A known amount of analyte is added to the sample after the sample has been digested. The % Recovery is calculated and tested against the specified upper and lower recovery limits.
The QC Spike sample is placed immediately after the matching sample or the matrix spike of the same sample.

If you enable the Spike test, the QC grid will display the following by default:

Check Box	Select which elements from the analysis are going to be governed by the QC pass criteria. You can select any you want, but if you have not selected an element, it will not be QC tested.
Defined Concentration	Enter the concentration of the relevant spike. The units used are the same as those defined in the Concentrations table on the Standards page.
Lower Limit	This is the lower acceptable limit for the QC read back listed as a percentage of the actual concentration entered in the defined concentration cell. For example, if the Lower Limit is set to 90% and your defined concentration is 1.0, then a read back greater than or equal to 0.9 (while still satisfying the Upper Limit requirements) would result in a QC test Pass.
Upper Limit	This is the upper acceptable limit for the QC read back listed as a percentage of the actual concentration entered in the defined concentration cell. For example, if the Upper Limit is set to 110% and your defined concentration is 1.0, then a read back less than or equal to 1.1, (while still satisfying the Lower Limit requirements) would result in a QC test Pass.

In a QC spike check, the concentration values for both the QC spike sample and its preceding sample are determined.

(MeasuredConc - MeasuredConc(PreviousSample)) / DefinedConc * 100

where:

MeasuredConc is the spiked sample result MeasuredConc(PreviousSample) is the sample result DefinedConc is the spike concentration

Ideally, where the sample matrix is equivalent in the two samples and in the calibration standards, the percentage recovery should equal 100.

The test is deemed to fail if the percentage is found to be greater than the upper limit or less than the lower limit. The default failure flag is W.

QC Spikes can be included in an analysis by selecting them from the Sequence page. The action taken will depend upon the Error Action selection made in the QC page.

Matrix Spike (MSPK)

A Matrix Spike is a Pre-digest spike. An aliquot of the sample spiked with known quantities of specific compounds is subjected to the entire analytical procedure, in order to indicate the appropriateness of the method for the matrix by measuring recovery. The % Recovery of the analyte indicates the effects of the preparation procedures on the recovery of the analyte.

If you enable the MSPK test, the QC grid will display the following by default:

Check Box	Select which elements from the analysis are going to be governed by the QC pass criteria. You can select any you want, but if you have not selected an element, it will not be QC tested.
Defined Concentration	Enter the concentration of the relevant spike. The units used are the same as those defined in the Concentrations table on the Standards page.
Lower Limit	This is the lower acceptable limit for the QC read back listed as a percentage of the actual concentration entered in the defined concentration cell. For example, if the Lower Limit is set to 90% and your defined concentration is 1.0, then a read back greater than or equal to 0.9 (while still satisfying the Upper Limit requirements) would result in a QC test Pass.
Upper Limit	This is the upper acceptable limit for the QC read back listed as a percentage of the actual concentration entered in the defined concentration cell. For example, if the Upper Limit is set to 110% and your defined concentration is 1.0, then a read back less than or equal to 1.1, (while still satisfying the Lower Limit requirements) would result in a QC test Pass.

In a Matrix spike check, the concentration values for both the QC spike sample and its preceding sample are determined.

(MeasuredConc - MeasuredConc(PreviousSample)) / DefinedConc * 100

where:

MeasuredConc is the spiked sample result MeasuredConc(PreviousSample) is the sample result DefinedConc is the spike concentration

Ideally, where the sample matrix is equivalent in the two samples and in the calibration standards, the percentage recovery should equal 100.

The test is deemed to fail if the percentage is found to be greater than the upper limit or less than the lower limit. The default failure flag is N.

Matrix Spikes can be included in an analysis by selecting them from the Sequence page. The action taken will depend upon the Error Action selection made in the QC page.

Matrix Spike Duplicate (MSD)

If you enable the MSD test, the QC grid will display the following by default:

Element	Select which elements from the analysis are going to be governed by the QC pass criteria. You can select any you want, but if you have not selected an element, it will not be QC tested.
Defined Concentration	Enter the concentration of the relevant spike. The units used are the same as those defined in the Concentrations table on the Standards page.
Lower Limit	This is the lower acceptable limit for the QC read back listed as a percentage of the actual concentration entered in the defined concentration cell. For example, if the Lower Limit is set to 90% and your defined concentration is 1.0, then a read back greater than or equal to 0.9 (while still satisfying the Upper Limit requirements) would result in a QC test Pass.
Upper Limit	This is the upper acceptable limit for the QC read back listed as a percentage of the actual concentration entered in the defined concentration cell. For example, if the Upper Limit is set to 110% and your defined concentration is 1.0, then a read back less than or equal to 1.1, (while still satisfying the Lower Limit requirements) would result in a QC test Pass.
% Difference	Enables you to set the allowable % difference limit between the sample and its corresponding duplicate. Default value is 20% difference.

The default failure flag is M .

The equation for MSD is:

Matrix Spike

(MeasuredConc - MeasuredConc(PreviousSample)) / DefinedConc * 100

Duplicate

abs(MeasuredConc(MSPK) - MeasuredConc) / ((MeasuredConc(MSPK) + MeasuredConc) / 2) * 100

where:

MeasuredConc is the spiked sample MSD result MeasuredConc(PreviousSample) is the sample result DefinedConc is the spike concentration MeasuredConc(MSPK) is the previous matrix spike result

The test is deemed to fail if the matrix spike percentage is found to be greater than the upper limit or less than the lower limit or if the duplicate % Difference is greater than the specified limit or if the measured concentration is greater than 5 times the CRQL.

Matrix Spike Duplicates can be included in an analysis by selecting them from the Sequence page. The action taken will depend upon the Error Action selection made in the QC page.

Rinse

If you enable the Rinse test, the QC grid will display the following by default:

Element

Select which elements from the analysis are going to be governed by the QC pass criteria. You can select any you want, but if you have not selected an element, it will not be QC tested.

This test is used to add an additional rinse after a solution. The concentration of the solution is reported. Unless the pass/fail criteria is modified, the test will only report and not perform an error action.

Sample Aggregate (SSUM)

If you enable the SSUM test, the QC grid will display the following by default:

Check Box	Select which elements from the analysis are going to be governed by the QC pass criteria. You can select any you want, but if you have not selected an element, it will not be QC tested.
Defined Concentration	Enter the concentration of the relevant element. The units used are the same as those defined in the Concentrations table on the Standards page.
Units	This information is specified on the Standards page.
Lower Limit	This is the lower acceptable limit for the QC read back listed as a percentage of the actual concentration entered in the defined concentration cell. For example, if the Lower Limit is set to 90% and your defined concentration is 1.0, then a read back greater than or equal to 0.9 (while still satisfying the Upper Limit requirements) would result in a QC test Pass.
Upper Limit	This is the upper acceptable limit for the QC read back listed as a percentage of the actual concentration entered in the defined concentration cell. For example, if the Upper Limit is set to 110% and your defined concentration is 1.0, then a read back less than or equal to 1.1, (while still satisfying the Lower Limit requirements) would result in a QC test Pass.

In the standalone SSUM test, the aggregate statistics across groups of samples is calculated, so that summarized data for Average, Standard Deviation, %RSD, Minimum, and Maximum can be reported instead of individual measurement results. Multiple SSUM QCs can be defined and added to the same worksheet. If SSUM is deselected, but still present in the sequence, the result is still reported, however, the assigned error action (Stop, or Flag and Continue only) will not be performed.

The following calculations are available for each of the results types listed below.

Calculations available:

• Average (Average)
• Standard deviation (Sd)
• %RSD (RSD)
• Minimum (Min)
• Maximum (Max)

Result types available:

• Measured concentration (MeasuredConc, ConcRSD, DefinedConc)
• Intensity (Intensity, IntRSD)
• Intensity quotient*
• Corrected intensity quotient*
• Fineness*
• Karat*

*Only available when Standard Bracketing is selected in the worksheet Configuration page. See the Standard Bracketing page for more information on these options.

See the QC Test Definition Editing Keyword page for more information.

Example calculations:

Average(MeasuredConc)	Calculates the average of each MeasuredConc of all sample concentrations of the elements (selected on the QC page) preceding this SSUM QC test entry in the sequence until it reaches the next instance of the same SSUM entry or the beginning of the sequence.
Rsd(MeasuredConc)	Calculates the %RSD of each MeasuredConc of all sample concentrations of the elements (selected on the QC page) preceding this SSUM QC test entry in the sequence until it reaches the next instance of the same SSUM entry or the beginning of the sequence.
Average(ConcRSD)	Calculates the average of individual ConcRSD of all elements (selected on the QC page) preceding this SSUM QC test entry in the sequence until it reaches the next instance of the same SSUM entry or the beginning of the sequence.

The test is deemed to fail if the percentage is found to be greater than the upper limit or less than the lower limit.

The default failure flag is A.

The Sample Aggregate test can be included in an analysis by adding it on the Sequence page. The action taken will depend upon the Error Action selection made in the QC page. 

All Sample QC

f you enable the AllSampleQC test, the QC grid will display the following by default:

Check Box	Select which elements from the analysis are going to be governed by the QC pass criteria. You can select any you want, but if you have not selected an element, it will not be QC tested.
Defined Concentration	Enter the concentration of the relevant element. The units used are the same as those defined in the Concentrations table on the Standards page.
Units	This information is specified on the Standards page.
Lower Limit	This is the lower acceptable limit for the QC read back listed as a percentage of the actual concentration entered in the defined concentration cell. For example, if the Lower Limit is set to 90% and your defined concentration is 1.0, then a read back greater than or equal to 0.9 (while still satisfying the Upper Limit requirements) would result in a QC test Pass.
Upper Limit	This is the upper acceptable limit for the QC read back listed as a percentage of the actual concentration entered in the defined concentration cell. For example, if the Upper Limit is set to 110% and your defined concentration is 1.0, then a read back less than or equal to 1.1, (while still satisfying the Lower Limit requirements) would result in a QC test Pass.

The default failure flag is A1, and this will increment (A2, A3 etc.,) as additional All Sample QC definitions are included in the worksheet to differentiate the flags for each definition.

The default ‘report value’ equation for the All Sample QC is:
MeasuredConc / DefinedConc* 100
The default ‘pass test’ equation for the All Sample QC is:
(ReportValue >= LowerLimit) and (ReportValue <= UpperLimit)

The All Sample QC functions differently from the other QC tests in that it’s not a specific solution which can be inserted into the Sequence – it’s a test that can be run on all samples (or all samples of a specific ‘sample type’) to ensure that those samples meet the criteria defined in the equations. You can define which samples will be assessed by each individual All Sample QC definition by selecting either ‘All-Samples’ or a specified sample type in the drop-down menu under the Pass test field on the QC page.

Once the definitions are done, select the Sample Type in the Sample Type column.

The All Sample QC only allows for ‘flag and continue’ or ‘stop’ to be assigned as error actions.

LSpike

f you enable theLSpike test, the QC grid will display the following by default:

Check Box	Select which elements from the analysis are going to be governed by the QC pass criteria. You can select any you want, but if you have not selected an element, it will not be QC tested.
Defined Concentration	Enter the concentration of the relevant element. The units used are the same as those defined in the Concentrations table on the Standards page.
Units	This information is specified on the Standards page.
Lower Limit	This is the lower acceptable limit for the QC read back listed as a percentage of the actual concentration entered in the defined concentration cell. For example, if the Lower Limit is set to 90% and your defined concentration is 1.0, then a read back greater than or equal to 0.9 (while still satisfying the Upper Limit requirements) would result in a QC test Pass.
Upper Limit	This is the upper acceptable limit for the QC read back listed as a percentage of the actual concentration entered in the defined concentration cell. For example, if the Upper Limit is set to 110% and your defined concentration is 1.0, then a read back less than or equal to 1.1, (while still satisfying the Lower Limit requirements) would result in a QC test Pass.

The default failure flag is J.

The ‘report value’ equation for the LSpike is:
(MeasuredConc – MeasuredConc(PreviousSample)) / DefinedConc* 100
The default ‘pass test’ equation for the All Sample QC is:
(ReportValue >= LowerLimit) and (ReportValue <= UpperLimit)

These equations are uneditable for the LSpike QC type.

The LSpike is included as a test to help meet specific USP232/233 method validation requirements. It’s intended for use in determining whether the levels of contaminant elements in pharmaceutical products or components are within acceptable limits.

The LSpike has a calculator associated with it (on the QC page, above the QC grid) which helps to calculate spike concentrations that are equivalent to different multipliers of a value ‘J’. In the USP232/233 requirements a value of 1.0J is the maximum acceptable level of a contaminant element in a sample, accounting for the maximum daily dose of the pharmaceutical product being tested, the administration route for that product (i.e., lower concentrations of contaminants are allowed in drugs taken inhalationally than orally) and the sample preparation dilution.

All QC error actions can be assigned to the LSpike QC type.

Detection Limits

References:

1. 40 CFR Part 136, Appendix B
2. EPA Contract Laboratory Program Statement of Work for Superfund Analytical Methods (Multi-Media, Multi-Concentration) SFAM01.0 May 2019

See also:

• QC page
• Test types and failure flags