ASTM D6850-03

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Designation:D6850–03
Standard Guide for
QC of Screening Methods in Water
This standard is issued under the fixed designation D 6850; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope in the batch. The number of samples in the batch is defined by
the task group responsible for the method.
1.1 This guide covers general considerations for the Quality
3.2.2.1 Discussion—See Practice D 5847 for definition and
Control practices for use with screening methods for organic
discussion of batch and batch size.
and inorganic constituents in water. Methods are provided by
3.2.3 false negative, n—a negative response for a sample
variousstandardsettingbodies,governmentalagencies,aswell
that contains the target analyte(s) at or above the stated action
as many domestic and international manufacturers.
level.
1.2 This guide provides general QC procedures that are
3.2.4 false positive, n—a positive response for a sample that
applicable to a broad range of screening methodologies. These
contains the target analyte(s) below the stated action level.
procedures help to ensure the quality of data that is generated.
3.2.5 qualitative method, n—a validated method that detects
Additional, method-specific or project specific requirements
presence or absence of an analyte at a specified screening limit.
may be necessary. This guide also includes general consider-
3.2.6 screening limit, n—the concentration of analyte that
ations regarding proper utilization of screening methods.
can be determined with a given certainty. The task group
2. Referenced Documents responsible for the method establishes the determination of the
screening limit.
2.1 ASTM Standards:
3.2.7 screening method, n—a method that is used to sepa-
D 1129 Terminology Relating to Water
rate or categorize samples.
D 4840 Guide for Sampling Chain-of-Custody Procedures
3.2.7.1 Discussion—An example would be a method that
D 5172 Guide for Documenting the Standard Operating
provides results that would be used to separate samples into
Procedures Used for the Analysis of Water
those that contain an analyte above or below a specified action
D 5847 Practice for Writing Quality Control Specifications
level.
for Standard Test Methods for Water Analysis
3.2.8 semi-quantitative method Type 1, n—a method whose
D 5905 Practice for the Preparation of Substitute Wastewa-
results are given in specified, discreet concentration ranges.
ter
3.2.8.1 Discussion—Two types of examples of this would
3. Terminology
include semi-quantitative immunoassays or test strips. The
cutoff concentration of the ranges has been predefined.
3.1 Definitions—For definitions of terms used in this guide,
3.2.9 semi-quantitative method Type 2, n—a method whose
refer to Terminology D 1129 and Practice D 5847.
results are reported as a single number along with the stated
3.2 Definitions of Terms Specific to This Standard:
uncertainty.
3.2.1 action level, n—a concentration of the analyte of
3.2.9.1 Discussion—The uncertainty will be reported as
concern at which some further action is required or suggested.
(standard deviation of x at a concentration of y). The values of
3.2.2 batch, n—a set (group) of samples analyzed such that
x and y can be established from the Initial Demonstration of
results of analysis of the QC samples analyzed with the batch
Performance study.
areindicativeofthequalityoftheresultsofanalysisofsamples
4. Significance and Use
4.1 Screening methods are often used to determine the
This guide is under the jurisdiction of ASTM Committee D19 on Water and is
presence or absence of a specific analyte, groups of analytes,
the direct responsibility of Subcommittee D19.05 on Inorganic Constituents in
classes of compounds or other indicators of chemical com-
Water.
Current edition approved Jan. 10, 2003. Published January 2003.
pounds in order to determine if further analysis or action is
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
necessary. The determination whether to proceed with further
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
action is useful in reducing the number of negative results for
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. which the screening method serves as a surrogate.
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D6850–03
4.2 The use of screening methods, whether to generate 6.1.4 When performing matrix evaluations it is recom-
qualitative or semi-quantitative results, is increasingly becom- mended to use the actual matrix if possible. If not, a similar
ingausefultoolforregulatorymonitoring,processcontrol,and matrix should be used. Example: Use substitute wastewater, as
site characterization. The appropriate use of a screening described in Practice D 5905, for a wastewater matrix. This
method, or any other method for that matter, is dependent upon will determine the suitability of the method in the matrix of
the Data Quality Objectives (DQOs) that are defined by the interest. It is also suggested a laboratory control sample (LCS)
user of the data. be run in a representative matrix.
4.3 Persons responsible for assessing the quality of the data 6.1.5 It is recommended that all screening methods be
generatedbytheuseofscreeningmethodsshouldhavedetailed
compared to a reference method to provide further detail of the
Quality Control guidelines by which to assess data quality. screening methods capabilities and limitations. This is useful
when establishing or verifying false positives/ negatives and
5. Consideration for Selection of an Appropriate recoveries in actual samples.
Screening Method 6.1.6 Specific requirements of a QC system for screening
methods will be dependent upon the type of analysis being
5.1 The screening method chosen must be appropriate for
performed.
the Action Level of the project.
6.1.7 Semi-quantitative Type 2 methods require either pre-
5.2 The chosen screening method must allow for the nec-
paring a user-generated calibration curve prior to running
essary number of samples to be run in a timely manner, not to
analyses, or verifying the manufacturers pre-programmed cali-
exceed the storage limits of the sample as defined by the
bration curve with standards before or during sample analysis.
method.
6.2 Qualitative Methods:
5.3 Many s
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