ASTM D7678-17(2022)

Standard Test Method for Total Oil and Grease (TOG) and Total Petroleum Hydrocarbons (TPH) in Water and Wastewater with Solvent Extraction using Mid-IR Laser Spectroscopy

SIGNIFICANCE AND USE
5.1 The presence and concentration of total oil and grease as well as total petroleum hydrocoarbons, in domestic and industrial wastewater is of concern to the public because of its deleterious aesthetic effect and its impact on aquatic life.  
5.2 Regulations and standards have been established that require monitoring of total oil and grease as well as total petroleum hydrocarbons in water and wastewater.
SCOPE
1.1 This test method covers the determination of total oil and grease (TOG) and total petroleum hydrocarbons (TPH) in water and waste water that are extractable by this test method from an acidified sample with a cyclic aliphatic hydrocarbon (for example cyclohexane, cyclopentane) and measured by IR absorption in the region from 1370 cm–1 to 1380 cm–1 (7.25 μm to 7.30 μm) using a mid-IR laser spectrometer. Polar substances are removed by clean-up with Florisil.2  
1.2 This test method also considers the volatile fraction of petroleum hydrocarbons, which is lost by gravimetric methods that require solvent evaporation prior to weighing, as well as by solvent-less IR methods that require drying of the employed solid phase material prior to measurement. Similarly, a more complete fraction of extracted petroleum hydrocarbons are accessible by this test method as compared to GC methods that use a time window for quantification, as petroleum hydrocarbons eluting outside these windows are quantified too.  
1.3 This test method covers the range of 0.1 mg/L to 1000 mg/L and may be extended to a lower or higher level by extraction of a larger or smaller sample volume collected separately.  
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.5 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, health and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 14-Oct-2022
• ICS: 13.060.50 - Examination of water for chemical substances
• Technical Committee: D19 - Water
• Drafting Committee: D19.06 - Methods for Analysis for Organic Substances in Water

Relations

• Refers: ASTM D1129-13(2020)e2 - Standard Terminology Relating to Water
• Effective Date: 01-May-2020
• Refers: ASTM D2777-12 - Standard Practice for Determination of Precision and Bias of Applicable Test Methods of Committee D19 on Water
• Effective Date: 15-Jun-2012
• Refers: ASTM D3921-96(2011) - Standard Test Method for Oil and Grease and Petroleum Hydrocarbons in Water (Withdrawn 2013)
• Effective Date: 01-May-2011
• Refers: ASTM D3370-10 - Standard Practices for Sampling Water from Closed Conduits
• Effective Date: 01-Dec-2010
• Refers: ASTM D1129-10 - Standard Terminology Relating to Water
• Effective Date: 01-Mar-2010
• Refers: ASTM D3370-08 - Standard Practices for Sampling Water from Closed Conduits
• Effective Date: 01-Oct-2008
• Refers: ASTM D2777-08 - Standard Practice for Determination of Precision and Bias of Applicable Test Methods of Committee D19 on Water
• Effective Date: 15-Jan-2008
• Refers: ASTM D3370-07 - Standard Practices for Sampling Water from Closed Conduits
• Effective Date: 01-Dec-2007
• Refers: ASTM D1129-06a - Standard Terminology Relating to Water
• Effective Date: 01-Sep-2006
• Refers: ASTM D1129-06ae1 - Standard Terminology Relating to Water
• Effective Date: 01-Sep-2006
• Refers: ASTM D2777-06 - Standard Practice for Determination of Precision and Bias of Applicable Test Methods of Committee D19 on Water
• Effective Date: 15-Aug-2006
• Refers: ASTM E168-06 - Standard Practices for General Techniques of Infrared Quantitative Analysis (Withdrawn 2015)
• Effective Date: 01-Mar-2006
• Refers: ASTM D1193-06 - Standard Specification for Reagent Water
• Effective Date: 01-Mar-2006
• Refers: ASTM D1129-06 - Standard Terminology Relating to Water
• Effective Date: 15-Feb-2006
• Refers: ASTM D1129-04 - Standard Terminology Relating to Water
• Effective Date: 01-Mar-2004

Overview

ASTM D7678-17(2022) is the internationally recognized standard test method for determining Total Oil and Grease (TOG) and Total Petroleum Hydrocarbons (TPH) in water and wastewater. This method utilizes solvent extraction followed by analysis using mid-infrared (mid-IR) laser spectroscopy in the 1370 cm⁻¹ to 1380 cm⁻¹ spectral range. The standard, developed and maintained by ASTM International, addresses growing environmental and regulatory demands for accurate monitoring of oil, grease, and petroleum hydrocarbons in domestic and industrial water systems.

Ensuring compliance with environmental requirements, this method is critical for industries and municipalities that discharge wastewater to surface water or municipal treatment plants, helping to minimize harmful aesthetic effects and risks to aquatic life.

Key Topics

• Scope of Measurement:

  • Measurement of TOG and TPH ranging from 0.1 mg/L to 1000 mg/L in water and wastewater.
  • Method covers both volatile and non-volatile fractions, overcoming limitations of traditional gravimetric or GC-based approaches.
  • Use of cyclic aliphatic hydrocarbons (e.g., cyclohexane) for extraction, and mid-IR laser spectrometry for quantification.

• Environmental Significance:

  • Accurate quantification of hydrocarbons is essential to comply with national and international water quality standards.
  • Direct impact on public health, environmental protection, and aquatic life due to regulation of oil and grease discharges.

• Method Procedure:

  • Solvent extraction from acidified samples.
  • Removal of polar contaminants using Florisil clean-up prior to TPH measurement.
  • Measurement via mid-IR laser spectroscopy ensures comprehensive detection and quantification.

• Quality Control and Calibration:

  • Emphasizes the need for calibration verification and regular laboratory control samples.
  • Includes procedures for checking for matrix interferences, method blanks, and recovery rates.

Applications

ASTM D7678-17(2022) is widely adopted in environmental laboratories, industrial facilities, and municipal water treatment plants for monitoring and reporting:

• Regulatory Compliance:
  Facilities subject to regulations on wastewater discharge must routinely monitor TOG and TPH to ensure adherence to environmental permits and local, state, or federal guidelines.

• Industrial Wastewater Analysis:
  Refineries, petrochemical plants, and production facilities use this standard to analyze process water and effluent streams for oil and grease contamination.

• Municipal Wastewater Treatment:
  Treatment plants apply this test method to assess influent and effluent quality, ensuring safe discharge into water bodies.

• Environmental Monitoring:
  Key tool for environmental impact assessments, site remediation projects, and routine water quality monitoring programs.

Related Standards

Organizations and laboratories may pair ASTM D7678-17(2022) with several referenced or associated standards and regulations to ensure comprehensive water quality analysis:

• ASTM D1129: Terminology Relating to Water
• ASTM D2777: Practice for Determination of Precision and Bias of Applicable Test Methods of Committee D19 on Water
• ASTM D3370: Practices for Sampling Water from Flowing Process Streams
• ISO 9377-2: Determination of Hydrocarbon Oil Index (International equivalent for certain jurisdictions)
• 40 CFR Part 136: US EPA Guidelines Establishing Test Procedures for the Analysis of Pollutants

Practical Value

Adopting ASTM D7678-17(2022) benefits organizations by delivering a science-based, reproducible, and robust approach to monitoring oil and grease contamination in water. The method supports regulatory compliance, environmental stewardship, and helps minimize potential ecological and public health impacts associated with petroleum hydrocarbon pollution.

Keywords: ASTM D7678, Total Oil and Grease, TOG, Total Petroleum Hydrocarbons, TPH, water analysis, wastewater monitoring, solvent extraction, mid-IR laser spectroscopy, environmental compliance, oil in water testing.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D7678 − 17 (Reapproved 2022)
Standard Test Method for
Total Oil and Grease (TOG) and Total Petroleum
Hydrocarbons (TPH) in Water and Wastewater with Solvent
Extraction using Mid-IR Laser Spectroscopy
This standard is issued under the fixed designation D7678; 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 ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
1.1 This test method covers the determination of total oil
mendations issued by the World Trade Organization Technical
and grease (TOG) and total petroleum hydrocarbons (TPH) in
Barriers to Trade (TBT) Committee.
water and waste water that are extractable by this test method
from an acidified sample with a cyclic aliphatic hydrocarbon
2. Referenced Documents
(for example cyclohexane, cyclopentane) and measured by IR
–1 –1
2.1 ASTM Standards:
absorption in the region from 1370 cm to 1380 cm (7.25
D1129Terminology Relating to Water
µm to 7.30 µm) using a mid-IR laser spectrometer. Polar
D1193Specification for Reagent Water
substances are removed by clean-up with Florisil.
D2777Practice for Determination of Precision and Bias of
1.2 This test method also considers the volatile fraction of
Applicable Test Methods of Committee D19 on Water
petroleum hydrocarbons, which is lost by gravimetric methods
D3370Practices for Sampling Water from Flowing Process
that require solvent evaporation prior to weighing, as well as
Streams
bysolvent-lessIRmethodsthatrequiredryingoftheemployed
D3921Test Method For Oil and Grease and Petroleum
solid phase material prior to measurement. Similarly, a more
Hydrocarbons in Water (Withdrawn 2013)
complete fraction of extracted petroleum hydrocarbons are
D5847Practice for Writing Quality Control Specifications
accessiblebythistestmethodascomparedtoGCmethodsthat
for Standard Test Methods for Water Analysis
use a time window for quantification, as petroleum hydrocar-
E168Practices for General Techniques of Infrared Quanti-
bons eluting outside these windows are quantified too.
tative Analysis
1.3 This test method covers the range of 0.1 mg/L to 1000
2.2 ISO Standards:
mg/L and may be extended to a lower or higher level by
ISO 9377-2Determination of Hydrocarbon Oil Index
extraction of a larger or smaller sample volume collected
2.3 Code of Federal Regulations (CFR) Publications:
separately.
40 CFR Part 136Guidelines Establishing Test Procedures
1.4 The values stated in SI units are to be regarded as
for the Analysis of Pollutants
standard. No other units of measurement are included in this
49 CFR Part 172 Hazardous Materials Table, Special
standard.
Provisions, Hazardous Materials Communications, Emer-
1.5 This standard does not purport to address all of the
gency Response Information,Training Requirements, and
safety concerns, if any, associated with its use. It is the
Security Plans
responsibility 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.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
1.6 This international standard was developed in accor-
Standards volume information, refer to the standard’s Document Summary page on
dance with internationally recognized principles on standard-
the ASTM website.
The last approved version of this historical standard is referenced on
This test method is under the jurisdiction ofASTM Committee D19 on Water www.astm.org.
andisthedirectresponsibilityofSubcommitteeD19.06onMethodsforAnalysisfor Available from International Organization for Standardization (ISO), ISO
Organic Substances in Water. Central Secretariat, BIBC II, Chemin de Blandonnet 8, CP 401, 1214 Vernier,
Current edition approved Oct. 15, 2022. Published October 2022. Originally Geneva, Switzerland, http://www.iso.org.
approved in 2011. Last previous edition approved in 2017 as D7678 – 17. DOI: Available from U.S. Government Printing Office, Superintendent of
10.1520/D7678-17R22. Documents, 732 N. Capitol St., NW, Washington, DC 20401-0001, http://
Florisil is a trademark by U.S. Silica Company, Frederick, MD. www.access.gpo.gov.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7678 − 17 (2022)
3. Terminology length of the cells should be chosen for optimum signal to
noiseratioatthemeasurementwavelengths.Thiswillbe2mm
3.1 Definitions:
to3mmincaseofquantumcascadelaserbasedspectrometers.
3.1.1 For definitions of terms used in this standard, refer to
Longer path lengths may be appropriate, if more powerful
Terminology D1129 and Practices E168.
lasers become available.
3.2 Definitions of Terms Specific to This Standard:
7.3 Mid-infrared laser spectrometer with an optical power
3.2.1 grease, n—difference between measured value for
–1
>20 mW within the spectral region from 1370 cm to 1380
TOG and TPH of a sample.
–1
cm (7.25µmto7.30µm).Eitherdouble-beamorsingle-beam
3.2.2 total oil and grease (TOG), n—material that can be
and capable of measuring in the spectral region from 1370
extracted from water or wastewater by this test method and –1 –1
cm to 1380 cm (7.25 µm to 7.30 µm) or single-beam
which can be measured by infrared absorption in the region –1 –1
instrument tunable from 1370 cm to 1400 cm (7.14 µm to
–1 –1
from 1370 cm to 1380 cm . 7
7.30 µm).
3.2.3 total petroleum hydrocarbons (TPH), n—material that
7.4 Widemouthsamplebottle,madefromglass,suggested1
canbeextractedfromwaterorwastewaterbythistestmethod,
L, either with screw cap having a fluoropolymer liner or a
which remains in the extract after treatment with Na SO and
2 4
wide-necked glass flask with a ground neck and with either
Florisil, and which can be measured by infrared absorption in
glassorfluoropolymerstopper.Thesamplingbottleshallallow
–1 –1
the region from 1370 cm to 1380 cm .
direct extraction from the bottle.
4. Summary of Test Method
7.5 Micro-separator (for example, see Fig. X1.1), or other
suitable device for phase separation.
4.1 Hydrocarbons from an acidified 900-mL sample of
water or wastewater are extracted with 50 mL of solvent. The
7.6 Clean-up columns, made from glass, with frit of sinter
material, which is measured directly after extraction by mid-
porosity 2 (for example, see Fig. X1.2) or equivalent ready-
infraredlaserspectroscopyisreferredtoastotaloilandgrease
made clean-up column containing Na SO and Florisil (for
2 4
(TOG). The material, which is measured after the extract is
TPH measurements).
treated with sodium sulfate and Florisil to remove traces of
7.7 Glass bottle, 50 mL to 100 mL, with glass or fluoropo-
water as well as polar substances, and thereby producing a
lymer stopper, or crimped cap with lined PTFE septum.
solution containing non-polar material, and which is measured
7.8 Magnetic stirrer, with PTFE stir bar (optional).
by mid-infrared laser spectroscopy is referred to as total
petroleum hydrocarbons (TPH). The difference between TOG
7.9 Volumetric flasks, glass, various (50mL, 100mL, and
and TPH provides the amount of grease extracted from the
200 mL).
sample.
7.10 PTFE wash bottle.
5. Significance and Use
7.11 Volumetric pipettes,glass,various(10mL,20mL,and
5.1 Thepresenceandconcentrationoftotaloilandgreaseas
50 mL).
well as total petroleum hydrocoarbons, in domestic and indus-
7.12 Analytical balance.
trial wastewater is of concern to the public because of its
7.13 Graduated glass syringes, 5 µL and 25 µL.
deleterious aesthetic effect and its impact on aquatic life.
7.14 Benchtop shaker.
5.2 Regulations and standards have been established that
require monitoring of total oil and grease as well as total
7.15 Glass stirring rod (optional).
petroleum hydrocarbons in water and wastewater.
7.16 A 1.00-mL serological glass pipet graduated in
0.01-mL increments and a 5.00-mL serological glass pipet
6. Interferences
graduated in 0.1-mL increments, or equivalent (optional).
6.1 Soaps, detergents, surfactants, and other materials may
formemulsionsthatcouldreducetheamountofTOGandTPH
8. Reagents and Materials
extracted from a sample.This test method contains procedures
8.1 Purity of Reagents—Reagent grade chemicals shall be
that can assist the analyst in breaking such emulsions.
used in all tests. Unless otherwise indicated, it is intended that
6.2 Organic compounds and other materials not considered
allreagentsshallconformtothespecificationoftheCommittee
as oil and grease or petroleum hydrocarbons on the basis of
on Analytical Reagents of the American Chemical Society, if
chemical structure (for example, halogenated hydrocarbons)
such specifications are available. Other grades may be used,
may be extracted and measured by this test method.
provided it is first ascertained that the reagent is of sufficiently
high purity to permit its use without lessening the accuracy of
7. Apparatus
the determination.
7.1 All glassware that will come in contact with the sample
shall be thoroughly cleaned, rinsed with distilled water and
dried at 130°C. Prior to starting this procedure, the glassware
ThesolesourceofsupplyoftheOilinWateranalyzersknowntothecommittee
shall be rinsed with solvent and dried. at this time is QuantaRed Technologies GmbH. If you are aware of alternative
suppliers, please provide this information to ASTM International Headquarters.
7.2 Cell(s), calcium fluoride, two required for double-beam
Your comments will receive careful consideration at a meeting of the responsible
operation, one required for single-beam operation. The path technical committee, which you may attend.
D7678 − 17 (2022)
8.2 Purity of Water—Unless otherwise indicated, references volume. Use the entire sample because removing a portion
to laboratory or reagent water shall be understood to mean would not apportion the hydrocarbons that adhere to the bottle
reagent water conforming to Specification D1193, Type II. surfaces. The high probability that extractable matter may
adhere to sampling equipment and result in measurements that
8.3 Tetradecane—99.0 % minimum purity, for calibration.
havealowbias,precludesthecollectionofcompositesamples
8.4 Petroleum Hydrocarbons, similar in composition to
for determination of TOG and TPH. Therefore, samples must
petroleum hydrocarbons determined by this test method for
be collected as grab samples. If a composite measurement is
possible use as calibration material.
required, individual grab samples, collected at prescribed time
intervals, may be analyzed separately and the concentrations
8.5 Mineral Oil Type A (Diesel Oil without Additives) and
MineralOilTypeB(LubricatingOilwithoutAdditives)—These averaged. Alternatively, samples can be collected in the field
and composited in the laboratory. For example, collect three
oiltypesmaybeobtainedfromsuppliersoffinechemicalsand
mixed1:1(w:w).Themixturecanbestoredat1°Cto6°Cfor individual 300-mL samples over the course of a day. In the
laboratory, extract each 300-mLsample with 15 mLof solvent
up to six months. Alternatively, a readily prepared 1:1 (w:w)
mixture of these oils may be used (for example, BAM K010 ). andcombinetheextracts.Besuretodeterminethecorrectratio
of solvent volumes taken from each sample prior to measure-
8.6 Florisil—grain size 150 µm to 250 µm (60 mesh to 100
ment.
mesh), activated by heating to 140°C for 16 h and stored in a
desiccator. Florisil is a trademark name for a prepared diato-
10.3 Preserve the sample with a sufficient quantity of
maceous substance, mainly consisting of anhydrous magne- sulfuric acid (see 8.8) or hydrochloric acid (see 8.9)toapHof
sium silicate. 2 or lower and refrigerate at 1°C to 6°C from the time of
collectionuntilextraction.Theamountofacidrequiredwillbe
8.7 Sodium Sulfate (Na SO )—anhydrous, granular.
2 4
dependentuponthepHandbuffercapacityofthesampleatthe
8.8 Sulfuric Acid (1+1)—Slowly and carefully add 1 vol-
timeofcollection.Iftheamountofacidrequiredisnotknown,
ume of sulfuric acid (H SO , sp gr 1.84) to 1 volume of water,
2 4
performthepHmeasurementonaseparatesamplethatwillnot
stirring and cooling the solution during addition.
be analyzed. Introduction of pH paper to an actual sample or
sample cap may remove some oil from the sample. In case the
8.9 HydrochloricAcid,ACS,(1+1)—Mixequalvolumesof
concentrated HCl and water. bottlecontainingthesamplecannotbeweighedbeforeaddition
of the acid, the volume of acid added to each sample can be
8.10 Solvent—Cyclohexane (minimum purity 99.5 %) or
recorded, then subtracted from the final measured sample
cyclopentane (minimum purity 98.5 %).
amount. If the sample is to be shipped by commercial carrier,
8.11 Stearic Acid (C H O ), minimum purity 98 %.
18 36 2
U.S. Department of Transportation regulations limit the pH to
aminimum(see40CFRPart136,TableII,Footnote3)of1.15
9. Hazards
ifH SO isusedand1.96ifHClisused(see49CFRPart172).
2 4
9.1 Normal laboratory safety applies to this test method.
10.4 Samples shall be extracted and analyzed within one
Analystsshouldwearsafetyglasses,glovesandlabcoatswhen
week. Once extracted, the extract can be stored up to two
workingwithacids.AnalystsshouldreviewtheMaterialSafety
weeks at a temperature between 7°C and 10°C.
Data Sheets (MSDS) for all reagents used in this test method.
Additional hazards may be presented by the particular sample
11. Calibration
being tested so proper care must be taken.
11.1 To ensure analytical values obtained using this test
10. Sampling
method are valid and accurate within the confidence limits of
the test, the instrument manufacturer’s instructions and the
10.1 Collect the sample in accordance with the principles
following procedures must be followed while performing this
described in Practices D3370, using a glass bottle in accor-
test method.
dance with 7.4. Pre-rinse the sample bottle and cap with the
solventandweighthedriedbottlebeforesamplecollection.Do
NOTE 1—This test method uses cyclohexane as standard solvent as it is
not rinse the sample bottle with the sample to be analyzed. Do
widely available. However, other cyclic aliphatic hydrocarbons such as
cyclopentane may be used instead with very similar figures of merit in
not allow the sample to overflow from the bottle during
terms of precision and dynamic range. It is the responsibility of the user
collection. Preventing overflow may not be possible in all
to demonstrate equivalent performance when using solvents other than
sampling situations, however, measures should be taken to
cyclohexane.
minimize overflow at all times.
NOTE 2—For calibration of the instrument, standards prepared by
weighing tetradecane in solvent shall be used. This is different to former
10.2 Asample volume of about 900 mLis required for this
test methods (for example, Test Method D3921), which allow calibration
test. Weigh the bottle containing the sample to determine the
either with the type of petroleum hydrocarbon that is known to be present
actual sampled amount. Alternatively, record the sampled
in the sample of water or wastewater or, alternatively, using a defined
calibration material (for example, mixture of isooctane and cetane). The
purpose of defining one calibration material is to facilitate comparability
of results obtained by different laboratories. Tetradecane was selected as
The sole source of supply of the prepared mixture BAM K010 known to the
calibration material, as it correlates best with different types of petroleum
committee at this time is the German Federal Institute for Materials Research and
hydrocarbons including heavy crude oil and condensate. In case the
Testing. If you are aware of alternative suppliers, please provide this information to
ASTM International Headquarters. Your comments will receive careful consider- concentrationofpetroleumhydrocarboninaconstantmatrixvoidofother
ation at a meeting of the responsible technical committee, which you may attend. extractable materials (for example process monitoring of crude oil in
D7678 − 17 (2022)
water)istobedetermined,calibrationoftheinstrumentmaybedonewith Follow recommendations of the manufacturer of laser based
the type of petroleum hydrocarbon awaiting analysis. In this special case, spectrometers, since variations in design make it impractical to offer
the clean-up step may be omitted and the extract measured directly after
instructions for their use with this test method.
solvent extraction. However, measurement of the calibration standards
11.4.1 The calibration contains a minimum of 6 non-zero
and the samples must be done in the same way. The thus obtained values
(oil in water) are, however, not to be considered as the total petroleum
points.
hydrocarbon (TPH) concentration of the sample in accordance with this
11.4.2 Check Cell for Cleanliness—For double-beam
test method.An appropriate correction factor can be found to relate such
analyzers, fill the reference cell and the sample cell with
values to the total petroleum hydrocarbon concentration in accordance
–1
with this test method (see 11.4.6 and 14.4). It lies within the sole
solventandrecordtheintensitieswithinthe1370cm to1380
–1
responsibility of the user to assure comparability of the results.
cm (7.25 µm to 7.30 µm) band. For single-beam analyzers,
11.2 Preparation of the Calibration Solutions: perform two consecutive measurements (I and I ). For a
0 x
–1 –1
11.2.1 Calibration Stock Solution S—Weigha100-mLvolu-
tunable analyzer, record I from the 1370 cm to 1380 cm
x
–1
metric flask including stopper. Draw about 1.800 g of tetrade-
band and I from 1400 cm (7.14 µm) and subtract the thus
cane or the type of the petroleum hydrocarbon awaiting
calculated absorbance value. The standard deviation of 3
–3
analysis (if available) and transfer it to this flask. Obtain its
absorbance values (see Eq 1) should be less than 60.2×10
exact weight by difference weighing. Fill to the mark with
Absorbance (dimensionless quantity, referred to as absorbance
solvent and mix the liquid well by shaking the flask. Calculate
value). If higher, check cells for cleanliness, matching,
theexactconcentrationofthecalibrationmaterialinsolutionin
alignment, etc., and repeat the procedure.
terms of mg/L.
11.4.3 Usesolventfromthesamebottleusedforpreparation
11.2.2 Calibration Solution G—Draw 50.0 mL of Stock
of the calibration solutions for background measurements (I )
Solution, transfer it to a 100 mL volumetric flask and fill the
and, in case of a single beam analyzer, perform a background
flask to the mark with solvent. Calibration Solution G = 9000
measurement (I ) before every measurement of a calibration
mg/L.
solution, unless otherwise instructed by the instrument manu-
11.2.3 Calibration Solution F—Draw 10.0 mL of Stock
facturer.
Solution, transfer it to a 100 mL volumetric flask and fill to
11.4.4 For calibrating the instrument in the concentration
mark with solvent. Calibration Solution F = 1800 mg/L.
range between 9 mg/Land 18 000 mg/Ltetradecane in solvent
11.2.4 Calibration Solution E—Draw 10.0 mL of Calibra-
(correspondingto0.5mg/Lto1000mg/Ltetradecaneinwater,
tionSolutionG,transferittoa100mLvolumetricflaskandfill
to mark with solvent. Calibration Solution E = 900 mg/L. considering an enrichment factor of the solvent extraction of
11.2.5 Calibration Solution D—Draw 10.0 mL of Calibra- 18, which results, if 900 mL of aqueous sample is extracted
tionSolutionF,transferittoa100mLvolumetricflaskandfill
with 50 mL of solvent), repeat the following procedure for
to mark with solvent. Calibration Solution D = 180 mg/L.
measurement of Calibration SolutionsA–G and S: Fill sample
11.2.6 Calibration Solution C—Draw 10.0 mL of Calibra-
cell with calibration solution or stock solution, respectively,
-1
tionSolutionE,transferittoa100mLvolumetricflaskandfill
andobtaintheabsorbancevalueswithinthe1370cm to1380
-1
to mark with solvent. Calibration SolutionC=90 mg/L.
cm band (7.25 µm to 7.30 µm) for every solution as
11.2.7 Calibration Solution B—Draw 10.0 mL of Calibra-
recommended by the instrument manufacturer. Alternatively,
tionSolutionD,transferittoa100mLvolumetricflaskandfill
calculatetheabsorbancevalueforeachstandard(A )usingthe
x
to mark with solvent. Calibration SolutionB=18 mg/L.
following equation:
11.2.8 Calibration Solution A—Draw 10.0 mL of Calibra-
I
tionSolutionC,transferittoa100mLvolumetricflaskandfill
A 5 log (1)
x
I
x
to mark with solvent. Calibration Solution A = 9 mg/L.
11.3 Preparation of the Laboratory Control Sample (LCS):
11.4.5 Plottheabsorbancevaluesfoundin11.4.4versusthe
11.3.1 Pour 900 mL reagent water into a sample bottle.
respective concentration values (in mg/L) for each of the
Record exact volume or weight.
solutions examined. The points should lie close to a straight
11.3.2 Using a micro-syringe, add 9.0 mg of a mixture of
line. Determine the equation of the best-fitting straight line by
mineral oil TypeAand Type B (8.5) to obtain a concentration
alinearregressiontechnique.Recordthisequationforusewith
o
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