1、Designation:D484188(Reapproved 2018)Standard Practice forEstimation of Holding Time for Water Samples ContainingOrganic and Inorganic Constituents1This standard is issued under the fixed designation D4841;the number immediately following the designation indicates the year oforiginal adoption or,in t
2、he case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This practice covers the means of estimating the periodof time during which a water sample
3、can be stored aftercollection and preservation without significantly affecting theaccuracy of analysis.1.2 The maximum holding time is dependent upon thematrix used and the specific analyte of interest.Therefore,water samples from a specific source must be tested todetermine the period of time that
4、sample integrity is maintainedby standard preservation practices.1.3 In the event that it is not possible to analyze the sampleimmediately at the time of collection,this practice does notprovide information regarding degradation of the constituent ofinterest or changes in the matrix that may occur f
5、rom the timeof sample collection to the time of the initial analysis.1.4 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.5 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is
6、 theresponsibility of the user of this standard to establish appro-priate safety,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.6 This international standard was developed in accor-dance with internationally recognized principles on stand
7、ard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:2D1129 Terminology Relating to WaterD1193 Specifica
8、tion for Reagent WaterD2777 Practice for Determination of Precision and Bias ofApplicable Test Methods of Committee D19 on WaterD3694 Practices for Preparation of Sample Containers andfor Preservation of Organic ConstituentsD4210 Practice for Intralaboratory Quality Control Proce-dures and a Discuss
9、ion on Reporting Low-Level Data(Withdrawn 2002)3D4375 Practice for Basic Statistics in Committee D19 onWaterE178 Practice for Dealing With Outlying Observations3.Terminology3.1 DefinitionsFor definitions of terms used in thisstandard,refer to Terminology D1129.3.1.1 criterion of detection,nthe minim
10、um quantity thatmust be observed before it can be stated that a substance hasbeen discerned with an acceptable probability that the state-ment is true(see Practice D4210).3.2 Definitions of Terms Specific to This Standard:3.2.1 acceptable holding time,nany period of time lessthan or equal to the max
11、imum holding time.3.2.2 maximum holding time,nthe maximum period oftime during which a properly preserved sample can be storedbefore such degradation of the constituent of interest or changein sample matrix occurs that the systematic error exceeds the99%confidence interval(not to exceed 15%)of the t
12、estcalculated around the mean concentration found at zero time.4.Summary of Practice4.1 Holding time is estimated by means of replicate analy-ses at discrete time intervals using a large volume of a water1This practice is under the jurisdiction of ASTM Committee D19 on Water andis the direct respons
13、ibility of Subcommittee D19.02 on Quality Systems,Specification,and Statistics.Current edition approved Oct.15,2018.Published October 2018.Originallyapproved in 1988.Last previous edition approved in 2013 as D4841 88(2013)1.DOI:10.1520/D4841-88R18.2For referenced ASTM standards,visit the ASTM websit
14、e,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.Copyright ASTM International,100 B
15、arr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommend
16、ations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.1 sample that has been properly collected and preserved.Asufficient number of replicate analyses are performed to main-tain the 99%confidence interval within 15%of the concen-tration found at zero time.Concentration of the constituent ofinterest is plotted versus time.The maximum holding time isthe period of time from sample collection to such time thatdegradation of the constituent of interest or change in s