1、Designation: D6850 03 (Reapproved 2008)D6850 13Standard Guide forQC of Screening Methods in Water1This standard is issued under the fixed designation D6850; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision.
2、 A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope Scope*1.1 This guide covers general considerations for the Quality Control practices for use with screening methods for organic andinor
3、ganic constituents in water. Methods are provided by various standard setting bodies, governmental agencies, as well as manydomestic and international manufacturers.1.2 This guide provides general QC procedures that are applicable to a broad range of screening methodologies. Theseprocedures help to
4、ensure the quality of data that is generated. Additional, method-specific or project specific requirements maybe necessary. This guide also includes general considerations regarding proper utilization of screening methods.1.3 The values stated in SI units are to be regarded as standard. No other uni
5、ts of measurement are included in this standard.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regu
6、latorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D1129 Terminology Relating to WaterD4840 Guide for Sample Chain-of-Custody ProceduresD5172 Guide for Documenting the Standard Operating Procedures Used for the Analysis of WaterD5847 Practice for Writing Quality Control Specif
7、ications for Standard Test Methods for Water AnalysisD5905 Practice for the Preparation of Substitute Wastewater3. Terminology3.1 DefinitionsFor definitions of terms used in this guide, refer to Terminology D1129 and Practice D5847.3.2 Definitions of Terms Specific to This Standard:3.2.1 action leve
8、l, na concentration of the analyte of concern at which some further action is required or suggested.3.2.2 batch, na set (group) of samples analyzed such that results of analysis of the QC samples analyzed with the batch areindicative of the along with QC samples; the quality of the results of analys
9、is of samples in the batch. The number of samples inthe batch is defined by the task group responsible for the method.sample-sets results is indicated by the results from the QCsamples.3.2.2.1 DiscussionThe number of samples in the batch is defined by the task group responsible for the method. See P
10、ractice D5847 for definition anddiscussion of batch and batch size.3.2.3 false negative, na negative response for a sample that contains the target analyte(s) at or above the stated action level.3.2.4 false positive, na positive response for a sample that contains the target analyte(s) below the sta
11、ted action level.3.2.5 qualitative method, na validated method that detects presence or absence of an analyte at a specified screening limit.1 This guide is under the jurisdiction of ASTM Committee D19 on Water and is the direct responsibility of Subcommittee D19.05 on Inorganic Constituents in Wate
12、r.Current edition approved May 1, 2008Aug. 1, 2013. Published May 2008August 2013. Originally approved in 2003. Last previous edition approved in 20032008 asD6850 03.D6850 03 (2008). DOI: 10.1520/D6850-03R08.10.1520/D6850-13.2 For referencedASTM standards, visit theASTM website, www.astm.org, or con
13、tactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have be
14、en made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official documen
15、t.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.2.6 screening limit, nthe concentration of analyte that can be determined with a given certainty. The task group resp
16、onsiblefor the method establishes the determination of the screening limit.3.2.6.1 DiscussionThe task group responsible for the method establishes the value of the screening limit.3.2.7 screening method, na method that is used to separate or categorize samples.3.2.7.1 DiscussionAn example would be a
17、 method that provides results that would be used to separate samples into into: (1) those that contain ananalyte and (2) those that do not contain and analyte above or below a specified action level.3.2.8 semi-quantitative method Type 1, na method whose results are given in specified, discreet conce
18、ntration ranges.3.2.8.1 DiscussionTwo types of examples of this method would include semi-quantitative immunoassays or test strips. The cutoff concentration ofthe ranges has been predefined.3.2.9 semi-quantitative method Type 2, na method whose results are reported as a single number along with the
19、stateduncertainty.3.2.9.1 DiscussionThe uncertainty will be reported as (standard deviation of x at a concentration of y). The values of x and y can be established fromthe Initial Demonstration of Performance study.4. Significance and Use4.1 Screening methods are often used to determine the presence
20、 or absence of a specific analyte, groups of analytes, classes ofcompounds or other indicators of chemical compounds in order to determine if further analysis or action is necessary. Thedetermination whether to proceed with further action is useful in reducing the number of negative results for whic
21、h the screeningmethod serves as a surrogate.4.2 The use of screening methods, whether to generate qualitative or semi-quantitative results, is increasingly becoming a usefultool for regulatory monitoring, process control, and site characterization. The appropriate use of a screening method, or any o
22、thermethod for that matter, is dependent upon the Data Quality Objectives (DQOs) that are defined by the user of the data.4.3 Persons responsible for assessing the quality of the data generated by the use of screening methods should have detailedQuality Control guidelines by which to assess data qua
23、lity.5. Consideration for Selection of an Appropriate Screening Method5.1 The screening method chosen must be appropriate for the Action Level of the project.5.2 The chosen screening method must allow for the necessary number of samples to be run in a timely manner, not to exceedthe storage limits o
24、f the sample as defined by the method.5.3 Many screening methods will give a positive result for several compounds or class of compounds. It must be determinedif a more specific method is necessary to eliminate these positive results.5.4 It is essential that an appropriate documentation system be es
25、tablished. A Standard Operating Procedure (SOP) for thescreening method containing the appropriate QC elements from this guide must be available. See Guides D4840 and D5172 forinformation on establishing a SOP for a method.5.5 Issues relating to timeliness of sample collection and analysis should be
26、 considered when selecting an appropriate screeningmethod. For example, for analyses that must be run immediately following sample collection, a method capable of being run inthe field may be necessary.5.6 When selecting a field screening method, considerations must be given to the expected field co
27、nditions. Factors such ashumidity, power requirements, temperature, effects of ambient lighting, etc must be addressed.6. Structure of a Quality Control System for Screening Methods6.1 General Considerations:D6850 1326.1.1 Due to possible difficulties in performing several of these requirements in t
28、he field it is acceptable to perform those QCrequirements in the laboratory.6.1.2 The following are suggested at a minimum for ongoing QC.6.1.2.1 Run a method blank containing no analyte, using reagent water as described in Specification D1193, with every batchto verify the test will produce a negat
29、ive result.6.1.2.2 Run a standard or set of standards with every batch. This may also serve as the calibration verification.6.1.2.3 Run a sample duplicate with every batch. Ensure that the replicate results meet the methods performance criteria.6.1.3 It is required that the analyst using the screeni
30、ng method proves their proficiency with the test. The task group responsiblefor the method will establish proficiency requirements.6.1.4 When performing matrix evaluations it is recommended to use the actual matrix if possible. If not, a similar matrix shouldbe used. Example: Use substitute wastewat
31、er, as described in Practice D5905, for a wastewater matrix. This will determine thesuitability of the method in the matrix of interest. It is also suggested a laboratory control sample (LCS) be run in a representativematrix.6.1.5 It is recommended that all screening methods be compared to a referen
32、ce method to provide further detail of the screeningmethods capabilities and limitations. This is useful when establishing or verifying false positives/ negatives positives/negatives andrecoveries in actual samples.6.1.6 Specific requirements of a QC system for screening methods will be dependent up
33、on the type of analysis being performed.6.1.7 Semi-quantitative Type 2 methods require either preparing a user-generated calibration curve prior to running analyses,or verifying the manufacturers pre-programmed calibration curve with standards before or during sample analysis.6.2 Qualitative Methods
34、:6.2.1 The following tests are recommended.6.2.1.1 Run a method blank containing no analyte to verify the test will produce a negative result.6.2.1.2 Run a standard of the analyte of interest to verify the test will produce a positive result.6.2.1.3 Establish the screening limit of the method. Ensur
35、e the screening limit is below the action level of interest.6.2.1.4 If possible run a representative matrix without the target analyte and verify a negative response. Spike the sample withthe target analyte and verify a positive response.6.3 Semi-Quantitative Type 1 Methods : Methods:6.3.1 It is sug
36、gested all of the tests for qualitative methods are performed plus these additional analyses.6.3.1.1 Run standards that have concentrations at the predefined concentration cutoffs. For some methods this will serve as thecalibration and for others it will be a calibration verification.6.3.1.2 Perform
37、 a matrix spike; ensure the results are in the appropriate concentration range.6.3.1.3 Perform a false positive/ false positive/false negative study at all of the concentrations of interest.6.3.1.4 Perform a precision study. When performing precision for semi-quantitative Type 1 methods the precisio
38、n will bereported as the number of times the result was in the same range. Example: 8 of 9 replicates fell in the concentration range of 5to 10 ppm.6.3.1.5 Perform a bias study. When performing bias for Semi-Quantitative Type 1 methods the bias will be based on whetherthe result was in the correct c
39、oncentration range. Example: When running a 7 ppm standard the result was in the range of 5 to 10ppm.6.4 Semi-Quantitative Type 2 Methods : Methods:6.4.1 It is suggested all of the tests for qualitative methods are performed plus these additional analyses.6.4.1.1 Perform a calibration or calibration
40、 verification of the method.6.4.1.2 Run a matrix spike; determine the recovery of the spike.6.4.1.3 Run a set of standards to determine the bias of the method.6.4.1.4 Perform a precision study. This will establish the uncertainty that is reported in the final result.7. Inter-laboratory Comparison7.1
41、 When performing an Inter-laboratory study the following should be considered.7.1.1 When determining precision for qualitative and Semi-Quantitative Type 1 methods define the precision as in 6.3.1.4.7.1.2 When performing bias for qualitative and Semi-Quantitative Type 1 methods define the bias as in
42、 6.3.1.5.7.1.3 Semi-Quantitative Type 2 methods can typically be evaluated as quantitative methods.8. Screening Method Validation8.1 A validated screening method will have had the following analyses performed.8.1.1 All of the appropriate quality control requirements from Section 6 will have been run
43、 within a single laboratory.8.1.2 The method will be run using an independent reference material (IRM).8.1.3 The method will be compared to a reference method.8.1.4 An inter-laboratory study will be performed.D6850 1339. Reporting Results9.1 All data that is generated following this guide must refer
44、ence this guide number and report the type of method performedas described in 3.2 (that is, qualitative, semi-quantitative Type 1, semi-quantitative Type 2).10. Keywords10.1 qualitative; quality control; screening; semi-quantitativeAPPENDIX(Nonmandatory Information)X1. ADDITIONAL LITERATURE RESOURCE
45、X1.1 The following literature was not reference in this document but is valuable for additional information on this subject.X1.1.1 Guide to Method Flexibility and Approval of EPA Water Methods, Draft Guide, December, 1996.SUMMARY OF CHANGESCommittee D19 has identified the location of selected change
46、s to this standard since the last issue (D6850 03(2008) that may impact the use of this standard. (Approved Aug. 1, 2013.)(1) Added 1.3 and 1.4.(2) Revised Section 3.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin thi
47、s standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be
48、 reviewed every five years andif not revised, either reapproved or withdrawn.Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of therespo
49、nsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM w
