ASTM D8001-16
(Test Method)Standard Test Method for Determination of Total Nitrogen, Total Kjeldahl Nitrogen by Calculation, and Total Phosphorus in Water, Wastewater by Ion Chromatography
Standard Test Method for Determination of Total Nitrogen, Total Kjeldahl Nitrogen by Calculation, and Total Phosphorus in Water, Wastewater by Ion Chromatography
SIGNIFICANCE AND USE
5.1 This test method allows the simultaneous determination of total nitrogen and total phosphorous from one sample digestion step.
5.2 This test method measures oxidized ammonia and organic nitrogen (as nitrate) and soluble nitrate simultaneously. By subtracting the nitrate + nitrite value from a non-digested sample gives a TKN:
When using this test method:
where:
TN = total nitrogen, and TKN = total Kjeldahl nitrogen.
SCOPE
1.1 This test method is applicable for the analysis total nitrogen (organic nitrogen + ammonia-N + nitrate-N + nitrite-N) as nitrate and total phosphorus as orthophosphate in unfiltered water samples by alkaline persulfate digestion followed by ion chromatography (IC).
1.2 Total Kjeldahl nitrogen (TKN) is determined by the calculation. To determine TKN subtract the nitrate-N and nitrite-N in a digested sample from a non-digested sample (see Section 4, Summary of Test Method).
1.3 The limit of detection (LOD), limit of quantitation (LOQ), and reporting range in Table 1 are based on the two-step process for this test method: digestion and analytical step. Because the digestion step requires a sample dilution, the LOD and LOQ are higher than undigested samples. The reporting range, LOD, and LOQ can be modified and perhaps improved depending on several factors (see Section 6, Interferences). (A) Ten calibration levels, each injected in duplicate.(B) LOD calculated as 3 × S/N.(C) LOQ calculated as 10 × S/N.(D)
where:
A = the average method blank concentration, = the student’s t-value for the single-tailed 99th percentile t statistic a standard deviation estimate with n – 1 degrees of freedom, and Sb = the sample standard deviation of the replicate blank analyses. (E) Phosphate LOD/LOQ was calculated based on a dilution factor of 15× relative to the system concentrations.
1.4 The method detection limits (MDL) are shown for reference. The digestion reagent contains background nitrate and results in higher detection limits. MDL will be shown after the interlaboratory study (ILS) is completed.
1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
General Information
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Designation: D8001 − 16
StandardTest Method for
Determination of Total Nitrogen, Total Kjeldahl Nitrogen by
Calculation, and Total Phosphorus in Water, Wastewater by
1
Ion Chromatography
This standard is issued under the fixed designation D8001; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 2. Referenced Documents
2
1.1 This test method is applicable for the analysis total 2.1 ASTM Standards:
nitrogen (organic nitrogen + ammonia-N + nitrate-N + D1129Terminology Relating to Water
nitrite-N) as nitrate and total phosphorus as orthophosphate in D1193Specification for Reagent Water
unfiltered water samples by alkaline persulfate digestion fol- D2777Practice for Determination of Precision and Bias of
lowed by ion chromatography (IC). Applicable Test Methods of Committee D19 on Water
D3856Guide for Management Systems in Laboratories
1.2 Total Kjeldahl nitrogen (TKN) is determined by the
Engaged in Analysis of Water
calculation. To determine TKN subtract the nitrate-N and
D4327Test Method forAnions in Water by Suppressed Ion
nitrite-N in a digested sample from a non-digested sample (see
Chromatography
Section 4, Summary of Test Method).
D5847Practice for Writing Quality Control Specifications
1.3 The limit of detection (LOD), limit of quantitation
for Standard Test Methods for Water Analysis
(LOQ), and reporting range in Table 1 are based on the
D5810Guide for Spiking into Aqueous Samples
two-step process for this test method: digestion and analytical
D6299Practice for Applying Statistical Quality Assurance
step. Because the digestion step requires a sample dilution, the
and Control Charting Techniques to Evaluate Analytical
LOD and LOQ are higher than undigested samples. The
Measurement System Performance
reporting range, LOD, and LOQ can be modified and perhaps
D6792Practice for Quality System in Petroleum Products
improved depending on several factors (see Section 6, Inter-
and Lubricants Testing Laboratories
ferences).
3. Terminology
1.4 The method detection limits (MDL) are shown for
3.1 Definitions:
reference. The digestion reagent contains background nitrate
3.1.1 For definitions of terms used in this standard, refer to
andresultsinhigherdetectionlimits.MDLwillbeshownafter
Terminology D1129.
the interlaboratory study (ILS) is completed.
3.2 Definitions of Terms Specific to This Standard:
1.5 The values stated in SI units are to be regarded as
3.2.1 total Kjeldahl nitrogen (TKN), n—the sum of organic
standard. No other units of measurement are included in this
nitrogen plus ammonia (NH ).
standard.
3
3.2.2 total nitrogen (TN), n—the sum of all nitrate, nitrite,
1.6 This standard does not purport to address all of the
ammonia, and organic nitrogen, as N, in water or wastewater
safety concerns, if any, associated with its use. It is the
samples.
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
3.2.3 total phosphorus (TP), n—the sum of
bility of regulatory limitations prior to use.
orthophosphates, polyphosphates, and organically bound
phosphates, as P, in water or wastewater samples.
1
This test method is under the jurisdiction ofASTM Committee D19 on Water
2
andisthedirectresponsibilityofSubcommitteeD19.06onMethodsforAnalysisfor For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Organic Substances in Water. contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Current edition approved July 15, 2016. Published August 2016. DOI: 10.1520/ Standards volume information, refer to the standard’s Document Summary page on
D8001-16. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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D8001 − 16
TABLE 1 Calibration, Linearity, Limits of Detection, and Quantitation from the Single Lab Validation Study
System Digested Sample
A
Calibration Range
Linearity
B C
Analyte LOD LOQ
2 LOD LOQ
(r )
(µg/L)
(µg/L) (µg/L)
(µg/L) (µg/L)
Nitrate-N 2.5–300 0.9999 0.76 2.5 — —
D
Nitrate-N 2.5–300 0.9999 1.0 3.4 171 171
E E
Phosphate-P 2.5–300 0.9999 1.3 4.2 19.5 63
A
Ten calibration levels, each injected in duplicate.
B
LODcalculatedas3×S/N.
C
LOQ calculated as 10 × S/N.
D
Nitrate MDL 5 A1t S
b sn 21,1 2 α 5 0.99d b
where:
A = the average method blank concentration,
= the student’s t-value for the single-tailed 99th percentile t statistic a standard deviation estimate with n – 1 degrees of freedom, and
t
n 21,1 2 α 5 0.99
s d
S = the sample standard deviation of the replica
...
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