1、Designation: D 6689 01 (Reapproved 2006)Standard Guide forOptimizing, Controlling and Reporting Test MethodUncertainties from Multiple Workstations in the SameLaboratory Organization1This standard is issued under the fixed designation D 6689; the number immediately following the designation indicate
2、s the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This guide describes a protocol for optimizin
3、g, control-ling, and reporting test method uncertainties from multipleworkstations in the same laboratory organization. It does notapply when different test methods, dissimilar instruments, ordifferent parts of the same laboratory organization functionindependently to validate or verify the accuracy
4、 of a specificanalytical measurement.1.2 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory req
5、uirements prior to use.2. Referenced Documents2.1 ASTM Standards:2D 1129 Terminology Relating to WaterD 6091 Practice for 99 %/95 % Interlaboratory DetectionEstimate (IDE) for Analytical Methods with NegligibleCalibration ErrorD 6512 Practice for Interlaboratory Quantitation EstimateE 135 Terminolog
6、y Relating to Analytical Chemistry forMetals, Ores, and Related MaterialsE 415 Test Method for Optical Emission Vacuum Spectro-metric Analysis of Carbon and Low-Alloy SteelE 1763 Guide for Interpretation and Use of Results fromInterlaboratory Testing of Chemical Analysis MethodsSTP 15D ASTM Manual o
7、n Presentation of Data and Con-trol Chart Analysis, Prepared by Committee E11 on Statis-tical Methods2.2 Other Documents:ISO 17025 (previously ISO Guide 25) General Require-ments for the Competence of Calibration and TestingLaboratories33. Terminology3.1 DefinitionsFor definitions of terms used in t
8、his Guide,refer to Terminology E 135 and D 1129.3.2 Defintions of Terms Specific to This Standard:3.2.1 laboratory organizationa business entity that pro-vides similar types of measurements from more than oneworkstation located in one or more laboratories, all of whichoperate under the same quality
9、system.NOTE 1Key aspects of a quality system are covered in ISO 17025 andinclude documenting procedures, application of statistical control tomeasurement processes and participation in proficiency testing.3.2.2 maximum deviationthe maximum error associatedwith a report value, at a specified confiden
10、ce level, for a givenconcentration of a given element, determined by a specificmethod, throughout a laboratory organization.3.2.3 measurement quality objectivesa model used by thelaboratory organization to specify the maximum error associ-ated with a report value, at a specified confidence level.3.2
11、.4 workstationa combination of people and equipmentthat executes a specific test method using a single specifiedmeasuring device to quantify one or more parameters, witheach report value having an established estimated uncertaintythat complies with the measurement quality objectives of thelaboratory
12、 organization.4. Significance and Use4.1 Many analytical laboratories comply with acceptedquality system requirements such as NELAC chapter 5 (seeNote 2) and ISO 17025. When using standard test methods,their test results on the same sample should agree with thosefrom other similar laboratories withi
13、n the reproducibilityestimates (R2) published in the standard. Reproducibilityestimates are generated during the standardization process as1This guide is under the jurisdiction of ASTM Committee D19 on Water and isthe direct responsibility of Subcommittee D19.02 on General Specifications,Technical R
14、esources, and Statistical Methods.Current edition approved Aug. 15, 2006. Published August 2006. Originallyapproved in 2001. Last previous edition approved in 2001 as D 6689 01.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. F
15、or Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from American National Standards Institute, 25 West 43rd St., 4thFloor, New York, New York, 10036.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Con
16、shohocken, PA 19428-2959, United States.part of the interlaboratory studies (ILS). Many laboratoriesparticipate in proficiency tests to confirm that they performconsistently over time. In both ILS and proficiency testingprotocols, it is generally assumed that only one workstation isused to generate
17、the data (see 6.5.1).NOTE 2NELAC chapter 5 allows the use of a Work Cell wheremultiple instruments/operators are treated as one unit: the performance ofthe Work Cell is tracked rather than each workstation independently. Thisguide is intended to go beyond the Work Cell to achieve the benefits ofmoni
18、toring workstations independently.4.2 Many laboratories have workloads and/or logisticalrequirements that dictate the use of multiple workstations.Some have multiple stations in the same area (central labora-tory format). Others stations are scattered throughout a facility(at-line laboratory format)
19、. Often, analysis reports do notidentify the workstation used for the testing, even if worksta-tions differ in their testing uncertainties. Problems can arise ifclients mistakenly attribute variation in report values to processrather then workstation variability. These problems can beminimized if th
20、e laboratory organization sets, complies with,and reports a unified set of measurement quality objectivesthroughout.4.3 This guide can be used to harmonize calibration andcontrol protocols for all workstations, thereby providing thesame level of measurement traceability and control. It stream-lines
21、documentation and training requirements, thereby facili-tating flexibility in personnel assignments. Finally, it offers anopportunity to claim traceability of proficiency test measure-ments to all included workstations, regardless on which work-station the proficiency test sample was tested. The pot
22、entialbenefits of utilizing this protocol increase with the number ofworkstations included in the laboratory organization.4.4 This guide can be used to identify and quantify benefitsderived from corrective actions relating to under-performingworkstations. It also provides means to track improved per
23、for-mance after improvements have been made.4.5 It is a prerequisite that all users of this guide complywith ISO 17025, especially including the use of documentedprocedures, the application of statistical control of measure-ment processes, and participation in proficiency testing.4.6 The general pri
24、nciples of this protocol can be adapted toother types of measurements, such as mechanical testing andon-line process control measurements such as temperature andthickness gauging. In these areas, users will likely need toestablish their own models for defining measurement qualityobjectives. Proficie
25、ncy testing may not be available or appli-cable.4.7 It is especially important that users of this guide takeresponsibility for ensuring the accuracy of the measurementsmade by the workstations to be operated under this protocol. Inaddition to the checks mentioned in 6.2.3, laboratories areencouraged
26、 to use other techniques, including, but not limitedto, analyzing some materials by independent methods, eitherwithin the same laboratory or in collaboration with otherequally competent laboratories. The risks associated withgenerating large volumes of data from carefully harmonized,but incorrectly
27、calibrated multiple workstations are obviousand must be avoided.5. Summary5.1 Identify the Test Method and establish the requiredmeasurement quality objectives to be met throughout thelaboratory organization.5.2 Identify the workstations to be included in the protocoland harmonize their experimental
28、 procedures, calibrations andcontrol strategies to be identical, so they will be statisticallycomparable.5.3 Tabulate performance data for each workstation andensure that each workstation complies with the laboratoryorganizations measurement quality objectives.5.4 Document items covered in 5.1-5.3.5
29、.5 Establish and document a laboratory organization-wideProficiency Test Policy that provides traceability to all work-stations.5.6 Operate each workstation independently as described inits associated documentation. If any changes are made to anyworkstation or its performance levels, document the ch
30、angesand ensure compliance with the laboratory organizationsmeasurement quality objectives.6. Procedure6.1 Identify the Test Method and establish the measurementquality objectives to be met throughout the laboratory organi-zation.6.1.1 Multi-element test methods can be handled concur-rently, if all
31、elements are measured using common technology,and the parameters that influence data quality are tabulated andevaluated for each element individually. An example is TestMethod E 415 that covers the analysis of plain carbon and lowalloy steel by optical emission vacuum spectrometry. Worksta-tions can
32、 be under manual or robotic control, as long as theestimated uncertainties are within the specified measurementquality objectives. Avoid handling multi-element test methodsthat concurrently use different measurement technologies.Their procedures and error evaluations are too diverse to beincorporate
33、d into one easy-to-manage package.6.1.2 Set the measurement quality objectives for the use ofthe Test Method throughout the laboratory organization, usingcustomer requirements and available performance data. At theconclusion of this effort, the laboratory organization will knowthe maximum deviation
34、allowable for any report value, at anyconcentration level, using the method of choice.An example ofa possible method for establishing measurement quality objec-tives is given in Appendix X1.6.2 Identify the workstations to be included in the protocoland harmonize their experimental procedures, calib
35、rations andcontrol strategies so that all performance data from all work-stations are directly statistically comparable.6.2.1 For each workstation, list the parameters (personnel,equipment, etc.) that significantly influence data quality. Eachcomponent of each workstation does not have to be identic
36、al(such as from the same manufacturer or model number).However, each workstation must perform the functions de-scribed in the test method.6.2.2 Harmonize the experimental procedures associatedwith each workstation to ensure that all stations are capable ofgenerating statistically comparable data tha
37、t can be expected toD 6689 01 (2006)2fall within the maximum allowable limits for the laboratoryorganization. Ideally, all workstations within the laboratoryorganization will have essentially the same experimental pro-cedures.TABLE 1 Sample SPC Control Parameter TabulationERMAssumedTrueConc.WS Av. U
38、CL LCL Std. Dev.C 638 0.06014 1 0.05996 0.06764 0.05228 0.002562 0.06040 0.06364 0.05716 0.001083 0.06005 0.06308 0.05702 0.00101648 0.25665 1 0.25212 0.27069 0.23355 0.006192 0.25923 0.27402 0.24444 0.004933 0.25861 0.27283 0.24439 0.00474Mn 638 0.29832 1 0.29620 0.30304 0.28936 0.002282 0.29967 0.
39、30567 0.29367 0.002003 0.29908 0.30643 0.29173 0.00245648 0.90328 1 0.90408 0.92088 0.88728 0.005642 0.90408 0.92385 0.88431 0.006593 0.90168 0.92664 0.87672 0.00832P 638 0.00563 1 0.00543 0.00600 0.00486 0.000192 0.00575 0.00605 0.00545 0.000103 0.00571 0.00601 0.00541 0.00010648 0.03431 1 0.03413
40、0.03674 0.03152 0.000872 0.03447 0.03702 0.03192 0.000853 0.03434 0.03689 0.03179 0.00085S 638 0.01820 1 0.01702 0.02146 0.01258 0.001482 0.01868 0.02153 0.01583 0.000953 0.01891 0.02128 0.01654 0.00079648 0.02424 1 0.02330 0.02771 0.01889 0.001472 0.02475 0.02940 0.02010 0.001553 0.02467 0.02884 0.
41、02050 0.00139Si 638 0.01688 1 0.01565 0.01718 0.01412 0.000512 0.01755 0.01863 0.01647 0.000363 0.01743 0.01830 0.01656 0.00029648 0.23283 1 0.22900 0.23911 0.21889 0.003372 0.23240 0.24404 0.22076 0.003883 0.23710 0.24619 0.22801 0.00303Cu 638 0.26588 1 0.26685 0.27555 0.25815 0.002902 0.26569 0.27
42、295 0.25843 0.002423 0.26511 0.27276 0.25746 0.00255648 0.10700 1 0.10654 0.11089 0.10219 0.001452 0.10753 0.11086 0.10420 0.001113 0.10694 0.13784 0.07604 0.01030Ni 638 0.69005 1 0.70014 0.72516 0.67512 0.008342 0.68252 0.69440 0.67064 0.003963 0.68750 0.71309 0.66191 0.00853648 0.25063 1 0.25174 0
43、.25906 0.24442 0.002442 0.24891 0.25350 0.24432 0.001533 0.25123 0.25927 0.24319 0.00268Cr 638 0.03746 1 0.03760 0.03886 0.03634 0.000422 0.03745 0.03832 0.03658 0.000293 0.03732 0.03813 0.03651 0.00027648 0.23728 1 0.23190 0.23637 0.22743 0.001492 0.24012 0.24414 0.23610 0.001343 0.23982 0.24300 0.
44、23664 0.00106Sn 638 0.00278 1 0.00255 0.00507 0.00003 0.000842 0.00257 0.00296 0.00218 0.000133 0.00322 0.00490 0.00154 0.00056648 0.01424 1 0.01402 0.01600 0.01204 0.000662 0.01412 0.01502 0.01322 0.000303 0.01458 0.01668 0.01248 0.00070Mo 638 0.06346 1 0.06253 0.06604 0.05902 0.001172 0.06398 0.06
45、533 0.06263 0.000453 0.06387 0.06621 0.06153 0.00078648 0.08652 1 0.08539 0.08995 0.08083 0.001522 0.08722 0.08941 0.08503 0.000733 0.08696 0.09011 0.08381 0.00105V 638 0.02107 1 0.02076 0.02184 0.01968 0.000362 0.02114 0.02219 0.02009 0.000353 0.02132 0.02231 0.02033 0.00033648 0.06937 1 0.06892 0.
46、07123 0.06661 0.000772 0.06949 0.07219 0.06679 0.00090TABLE 1 ContinuedERMAssumedTrueConc.WS Av. UCL LCL Std. Dev.3 0.06969 0.07233 0.06705 0.00088Ti 638 0.00224 1 0.00272 0.00296 0.00248 0.000082 0.00200 0.00200 0.00200 0.000003 0.00200 0.00200 0.00200 0.00000648 0.04279 1 0.04285 0.04726 0.03844 0
47、.001472 0.04285 0.04684 0.03886 0.001333 0.04268 0.04688 0.03848 0.00140Al 638 0.02346 1 0.02373 0.02964 0.01782 0.001972 0.02343 0.02646 0.02040 0.001013 0.02323 0.02584 0.02062 0.00087648 0.06268 1 0.06268 0.06721 0.05815 0.001512 0.06198 0.06633 0.05763 0.001453 0.06222 0.06576 0.05868 0.00118E =
48、 Element determinedRM = Reference material used for SPC controlAssumed True Conc. = Concentration of E in the RMWS = Work StationAv. = Grand Mean from the SPC chartUCL = Upper control limit from the SPC chartLCL = Lower control limit from the SPC chartStd. Dev. = Standard Deviation from the SPC char
49、t (UCL-LCL)/66.2.3 Harmonize calibration protocols so that equivalentcalibrants (i.e. same material source, same stock solutions) areused to cover the same calibration ranges for the same elementson all instruments (see Note 3). Avoid the use of differentcalibrants on different instruments that may lead to calibrationbiases and uncertainties that are larger than necessary. Makesure that all interferences and matrix effects are accounted for.Verify the calibrations with certified reference materials notused in the calibration, when possible. Record the findings foreach wor
