1、Designation:D 4210 89(Reapproved 1996)e1Standard Practice forIntralaboratory Quality Control Procedures and aDiscussion on Reporting Low-Level Data1This standard is issued under the fixed designation D 4210;the number immediately following the designation indicates the year oforiginal adoption or,in
2、 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.e1NOTEKeywords were added editorially in May 1996.1.Scope1.1 This practice is applicable to all lab
3、oratories that pro-vide chemical and physical measurements in water,and pro-vides guidelines for intralaboratory control and suggestedprocedures for reporting low-level data.1.2 The use of this practice is based on the assumptions thatthe analytical method used is appropriate for the task,is eithere
4、ssentially bias-free or the bias is known,is capable of beingbrought into a state of statistical control,and possessesadequate sensitivity to determine the analytes at the levels ofinterest.1.3 Further,it is assumed that quality assurance proceduresfor field operations such as sample collection,cont
5、ainer selec-tion,preservation,transportation,and storage are proper.1.4 This practice is also predicated upon the laboratoryalready having established a quality control system withdevelopment of an adequate reporting system such that thelaboratorys performance can be substantiated.2.Referenced Docum
6、ents2.1 ASTM Standards:D 1129 Terminology Relating to Water23.Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1control chartsa charting of the variability of aprocedure such that when some limit in variability is exceededthe method is deemed to be out of control.3.1.2 control limit
7、sthose upper and lower limits used tosignal that a procedure is out of control.3.1.3 criterion of detectionthe minimum quantity(ana-lytical result)which must be observed before it can be statedthat a substance has been discerned with an acceptable prob-ability that the statement is true(see 11.11).T
8、he criterion ofdetection must always be accompanied by the stated probabil-ity.3.1.4 in controlonce a reliable estimate of the populationstandard deviation is obtained,a deviation not exceeding 3s isconsidered to be in control.Allowing deviations up to 3s implyan a(alpha)5 0.0027 or about 3 chances
9、in 1000 of judging anin control procedure to be out of control.3.1.5 limit of detectiona concentration of twice the crite-rion of detection when it has been decided that the risk ofmaking a Type II error is to be equal to a Type I error(see11.11).3.1.6 Type I error,a(alpha)errora statement that asub
10、stance is present when it is not.3.1.7 Type II error,b(beta)errora statement that a sub-stance is not present(was not found)when the substance waspresent.3.2 DefinitionsFor definitions of other terms used in thispractice,refer to Terminology D 1129.4.Significance and Use4.1 Any analytical procedure
11、that is in statistical control willhave an inherent variability as one of its characteristics.For agiven procedure this variability is irreducible,that is,there isno identifiable factor or assignable cause that contributes toprocedure variation.4.2 The measure of procedure variability for this pract
12、ice isthe estimate of the population standard deviation.The specificpopulation of interest can be either within an analytical set orbetween set analyses or both.4.3 In considering low level reporting the question is:is thesubstance present?This practice will aid in determining therisk taken in assig
13、ning that a substance is present,when it isnot,and provide an assessment of criterion of detection.4.4 Procedure variability control limits are set by use ofShewhart control charts.35.Estimating Analytical Procedure Variability byDuplicate Analyses5.1 For a crude estimate of population standard devi
14、ation,initially conduct 5 or 6 duplicate analyses from samples ofnearly the same concentration.Accumulate additional data toobtain a reliable initial estimate of the population standard1This practice is under the jurisdiction of ASTM Committee D-19 on Water andis the responsibility of Subcommittee D
15、19.02 on General Specifications,TechnicalResources,and Statistical Methods.Current edition approved Jan.27,1989.Published March 1989.Originallypublished as D 4210 83.Last previous edition D 4210 83.2Annual Book of ASTM Standards,Vol 11.01.3“Presentation of Data and Control Chart Analysis,”ASTM STP 1
16、5-D,ASTM,1976,pp.93103.1AMERICAN SOCIETY FOR TESTING AND MATERIALS100 Barr Harbor Dr.,West Conshohocken,PA 19428Reprinted from the Annual Book of ASTM Standards.Copyright ASTMdeviation in which 40 to 50 data points(degrees of freedom)are needed.They may be analyses of duplicate samples orstandards determined either within analytical-set or betweensets depending on the information sought.However,withhighly labile constituents only within set analyses would beappropriate.5.2 After performing the d
