Section 149.44. Laboratory equipment.

 

(1)   General provisions .

(a) The laboratory shall be furnished with the equipment necessary and required for the correct performance of all the environmental tests and associated preparations and activities it performs.

(b) The equipment and software used for testing and calibration shall achieve the accuracy required to comply with the requirements of approved methods or specifications relevant to the environmental testing performed by the laboratory .

(2)   Laboratory support equipment.

(a) All support equipment shall be kept in working order by submitting it to routine and preventive maintenance.

(b) When support equipment leaves the direct control of the laboratory for maintenance or for any other reason, the laboratory shall ensure that the function and calibration status of that equipment is checked or demonstrated to be satisfactory before the equipment is returned to service.

(3)   Calibration and verification of support equipment.

(a) All support equipment shall be calibrated or verified over its range of use using available reference materials traceable to NIST. When reference materials traceable to NIST are not produced, manufactured or commercially available, the laboratory shall use materials of a quality that will ensure the accuracy of the calibrated or verified support equipment for its intended use.

(b) The acceptability criteria for these calibration verification checks shall be established by approved test methods, department guidance, or in their absence, tolerances established by manufacturers.

(c) When the results of the calibration or calibration verification of support equipment do not meet the specifications of the application or method for which the equipment is used, the equipment shall be removed from service until repaired; however, if the deviation from the calibration specifications results in a consistent bias, the equipment may remain in service if correction factors are applied to all measurements made with the deviating equipment.

(d) Devices used to measure the temperature of laboratory ovens, incubators, water baths, refrigerators, freezers and samples received at the laboratory shall be calibrated or verified at least yearly against thermometers traceable to NIST.

(e) The operating temperature of autoclaves, incubators, ovens and water baths used as part of a method shall be checked to meet the temperature requirements of that method each day they are used.

(f) Refrigerators, freezers, ovens and incubators holding samples continuously as part of standard operating conditions shall be checked on each day that laboratory personnel conduct analyses. The laboratory shall endeavor to set equipment settings and conditions that maintain required temperatures on days that personnel do not conduct analyses.

(g) Analytical balances that have been used at least once in a month shall be checked monthly with at least 2 certified weights, one weight in the gram range and one weight in the milligram range. The weights used to perform these checks shall be:

1. Traceable to NIST, and shall be of class or type suitable for verifying the accuracy of analytical balances.

2. Certified for accuracy every 5 years by a metrology service outside the laboratory or new individual weights of suitable class or type traceable to NIST shall be purchased for use. This re-certification shall be performed sooner than every 5 years if balance checks performed using these weights suggest that a change in the certified weight has occurred.

3. Handled and stored in a manner that protects their integrity.

(h) Non-analytical balances that have been used at least once in a month shall be checked monthly with at least one weight in the expected range of their use. The weights used to perform these checks may be traceable to or verified against those traceable to the NIST.

(i) Mechanical and automatic volumetric dispensing devices, including pipettes, micro-pipettes, burettes and automatic dilutors and dispensers shall be checked for accuracy at least quarterly when they are in use.

1. Glass microliter syringes do not need to be checked for accuracy if they are documented to be as accurate as class A glassware.

2. Disposable pipettes and any of the aforementioned devices which are dedicated to use in method steps or applications that do not require use of class A glassware are exempted from the quarterly verification of accuracy.

(4)   Laboratory analytical instruments.

(a) Laboratory analytical instruments shall be operated by personnel trained in their use. Instructions on the use and maintenance of equipment shall be available to instrument operators.

(b) All instruments shall be properly maintained, inspected and cleaned. The laboratory shall establish procedures for the maintenance of analytical instruments to prevent contamination or deterioration that may affect reported results.

(c) Analytical instruments that give suspect results or that have been shown to be defective or outside of performance specifications shall be taken out of service.

(d) When analytical instruments leave the direct control of the laboratory for maintenance or for any other reason, the laboratory shall ensure that the functional and calibration status of those analytical instruments are checked or demonstrated to be satisfactory before the instruments are returned to service.

(5)   Instrument calibration general provisions and requirements.

(a) All analytical instruments shall be calibrated at least once in any year in which they have been used, and shall be calibrated or their calibration verified before they are used to provide any quantitative results.

(b) When more stringent instrument initial calibration or continuing calibration verification requirements are required in mandated test methods or regulations, laboratories shall follow the more stringent requirements, unless:

1. A test method requires analyzing more than 3 standards to establish a linear calibration, and the laboratory chooses to narrow the calibration range of the determination to no more than 2 orders of magnitude and uses at least 3 standards to generate an initial calibration.

2. A test method requires analyzing more than one continuing calibration verification standard to verify a linear calibration and the laboratory has narrowed the calibration range of the determination to no more than 2 orders of magnitude and uses at least one standard to verify continued calibration.

(6)   Initial instrument calibration.

(a) The details of initial instrument calibration procedures, including, calculations, integrations, acceptance criteria and associated statistics shall be included or referenced in the test method standard operating procedure. When initial instrument calibration procedures are cited by reference in the test method standard operating procedure, the laboratory shall retain the referenced material.

(b) The laboratory shall select a calibration model that is appropriate for the expected behavior of the analytical instrument to be calibrated.

(c) To establish calibration, the laboratory shall select a number of non-zero standard concentrations that is appropriate for the calibration model selected and the expected range of concentrations. The number of calibration standards used shall also be sufficient to establish a relationship or corroborate a universally established theoretical relationship between instrument response and concentration that is appropriate for the specific instrument and its intended use.

(d) The minimum number of standard concentrations selected to establish calibration shall be 3 except for:

1. Dissolved oxygen meters, which shall be calibrated against water-saturated air, air-saturated water at a known temperature and pressure, or by reference to an aliquot of air-saturated water analyzed by the Winkler or iodometric method.

2. Ion selective electrodes and pH meters, the minimum number shall be 2.

3. Inductively coupled plasma emission spectrophotometers and inductively coupled plasma mass spectrometers, the minimum number shall be one.

4. Calibration models that are quadratic, the minimum shall be 5.

5. Calibration models that are cubic, the minimum shall be 7.

(e) The concentration of the standards chosen to establish a calibration function shall be within the same orders of magnitude as the expected concentration of samples to be quantitated with an initial calibration. Laboratories reporting results at levels at or near the limit of detection of an analysis shall include in initial calibrations a standard at a concentration near the limit of quantitation of the analysis.

(f) To generate a calibration function, the laboratory shall select a reduction technique or algorithm that is appropriate for the calibration model and number of standard concentrations selected.

1. The selected algorithm or reduction technique shall be describable mathematically, and shall provide equations, coefficients or parameters necessary to characterize the calibration function uniquely, unless an analytical instrument is tuned to conform to a universally accepted scientific law or scale.

2. The laboratory shall use the simplest linear calibration function unless it has documentation that a non-linear function provides a statistically improved definition of the calibration range. Non-linear functions may not be used to compensate for instrument saturation, insensitivity, or malfunction.

3. The laboratory may use weighted algorithms or reduction techniques, unless they are chosen to compensate for deviations from the expected behavior of a detector of an analytical instrument resulting from instrument saturation, insensitivity or malfunction.

4. The laboratory may not use reiterative reduction techniques or algorithms that force calibration functions through zero.

(g) The laboratory shall establish acceptability criteria for initial calibrations. The type of criteria chosen and the acceptance range shall be appropriate for the type of analytes to be quantitated, the calibration model selected and reduction technique or algorithm chosen.

1. When average response factors are used to reduce calibration data, the relative standard deviation of the response factors may not exceed 20%, unless an approved method of analysis allows a larger percentage.

2. When linear regression or least squares analysis is used to reduce calibration data for inorganic analytes and metals, the correlation coefficient of the resultant calibration curves shall be at least 0.995.

3. When linear regression or least squares analysis is used to reduce calibration data for organic analytes, the correlation coefficient of the resultant calibration curves shall be at least 0.99.

4. When quadratic regression analysis is used to reduce calibration data for inorganic analytes and metals, the coefficient of determination of the resultant calibration curves shall be at least 0.995.

5. When quadratic regression analysis is used to reduce calibration data for organic analytes, the coefficient of determination of the resultant calibration curves shall be at least 0.99.

(h) The laboratory shall establish procedures for zeroing an instrument and the treatment of calibration blanks, when the referenced analytical method used by the laboratory requires the response of a calibration blank to be part of a calibration function.

(i) Laboratories shall verify all initial instrument calibrations after they are generated but before they are used to quantitate any samples, with a second source standard, unless either of the following conditions exists:

1. An instrument is calibrated by tuning it to conform to a universally accepted scientific law or scale, as is the case with pH meters, ion selective electrodes and dissolved oxygen meters.

2. The laboratory analyzes quality control standards for the analyte or analyte group involved and evaluates them as specified in s. NR 149.48 (5) .

(j) Unless otherwise required by regulation, method or program, the acceptance criteria for this second source verification shall be that required under sub. (7) for continuing instrument calibration verification.

(k) Laboratories shall quantitate sample results only from initial instrument calibrations, unless otherwise allowed by regulation, method or covered program.

(L) Laboratories shall quantitate sample results from an instrument response that is within the range of the initial calibration. If sample dilution is required, the dilution shall be the lowest required to obtain an instrument response within the range of the initial calibration.

1. Except for samples analyzed by inductively coupled plasma emission spectrophotometers and inductively coupled plasma mass spectrometers, samples having responses greater than that of the most concentrated standard of an initial calibration allowed to be established with at least 3 different standard concentrations shall be diluted and reanalyzed. When samples cannot be diluted and reanalyzed, sample results shall be reported with appropriate qualifiers or narrative warnings.

2. Samples analyzed by inductively coupled plasma emission spectrophotometers and inductively coupled plasma mass spectrometers having responses at or above 90% of the established upper limit of the linear dynamic range of the instruments shall be diluted and reanalyzed. When samples cannot be diluted and reanalyzed, sample results shall be reported with appropriate qualifiers or narrative warnings.

3. Samples analyzed by inductively coupled plasma emission spectrophotometers and inductively coupled plasma mass spectrometers having responses below 90% of the established upper limit of the liner dynamic range of the instruments but above the response of the highest concentration of standard in an initial calibration may be reported without resorting to dilution.

(m) Once a calibration model is selected, a calibration function is established, and an initial calibration is finalized, a laboratory may not change the model or calibration function after samples have been analyzed without performing another initial calibration.

(n) Laboratories shall perform an initial calibration after instruments undergo non-routine maintenance, when repeated use or other conditions change their expected behavior, and when their continuing calibration cannot be verified.

(o) Except as allowed in s. NR 149.39 (3) (c) 12. , laboratories shall retain all the raw data necessary to reconstruct or reproduce, independently of analytical instruments, all calibration functions associated with initial calibrations.

(7)   Continuing instrument calibration verification.

(a) When an initial instrument calibration is not performed on the day of analysis, the validity of the initial calibration shall be verified prior to quantitating samples by continuing calibration verification with each analytical batch and at least once on each analysis day. Continuing calibration verification shall also be performed after the consecutive analysis of each group of 20 samples, if 20 or more samples constitute an analytical run. Continuing calibration verification is not required for analyses that cannot be spiked, such as BOD, cBOD and TSS, or those analyses that do not involve a calibration, such as titrations.

(b) The calibration standards analyzed to demonstrate continuing instrument calibration may be obtained from the same source used to generate an initial calibration.

(c) The number and concentration of calibration standards required to demonstrate continuing instrument calibration is outlined in Table 1 of this subchapter.

(d) The acceptance criteria for continuing calibration verification standards shall be those defined in the method utilized by the laboratory. If the reference method does not contain criteria, the acceptance criteria for continuing calibration shall be:

1. Obtaining concentrations within 10% of the respective actual concentrations of all reportable inorganic analytes and metals from an initial calibration.

2. Obtaining concentrations within 15% of the respective actual concentrations of all reportable organic analytes from an initial calibration.

(e) When the continuing calibration verification results obtained are outside acceptance criteria, the laboratory shall perform another calibration verification if the results of this second calibration verification fail to meet acceptance criteria, the laboratory shall take corrective action. After taking corrective action, the laboratory shall perform 2 consecutive calibration verifications that meet acceptance criteria or shall perform another initial calibration.

(f) Samples associated with a failing calibration verification shall be reanalyzed or reported with appropriate qualifiers.

(g) The details of the continuing instrument calibration procedure, calculations and associated statistics shall be included in the test method standard operating procedure. When continuing calibration verification procedures are cited by reference in the test method standard operating procedure, the laboratory shall retain the referenced material.

History: CR 06-005 : cr. Register April 2008 No. 628 , eff. 9-1-08.

Note

Department guidance documents are available for download from the department website at: http://www.dnr.state.wi.us/org/es/science/lc/OUTREACH/Guidance.htm . Microsoft Windows NT 6.1.7601 Service Pack 1 The response of dissolved oxygen meters is generally adjusted to conform to the concentration of oxygen allowable in a given fluid at a specified temperature and pressure. The response of an ion selective electrode is generally tuned to conform to the Nernst equation. The response of pH meters is tuned to conform to the universally accepted pH scale. When these instruments are adjusted or tuned according to these principles, characterizing the calibration reduction algorithm mathematically is not necessary. Microsoft Windows NT 6.1.7601 Service Pack 1 Reiterative reduction techniques or algorithms that force through zero obtain mathematically, by repeated application, a null response for a zero standard that has a non-zero response, or adjust calibration parameters to obtain a theoretical null response without analysis of a calibration blank. This paragraph does not prohibit the use of average response factors or automatic zeroing as part of an initial calibration, when methods, regulations or covered programs allow those techniques. Microsoft Windows NT 6.1.7601 Service Pack 1 Table 1
Requirements for Continuing Calibration Verification - See PDF for table Microsoft Windows NT 6.1.7601 Service Pack 1