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ASTM D7726-11

(Guide)

Standard Guide for The Use of Various Turbidimeter Technologies for Measurement of Turbidity in Water

Standard Guide for The Use of Various Turbidimeter Technologies for Measurement of Turbidity in Water

SIGNIFICANCE AND USE
Turbidity is a measure of scattered light that results from the interaction between a beam of light and particulate material in a liquid sample. Particulate material is typically undesirable in water from a health perspective and its removal is often required when the water is intended for consumption. Thus, turbidity has been used as a key indicator for water quality to assess the health and quality of environmental water sources. Higher turbidity values are typically associated with poorer water quality.
5.1.1 Turbidity is also used in environmental monitoring to assess the health and stability of water-based ecosystems such as in lakes, rivers and streams. In general, the lower the turbidity, the healthier the ecosystem.
Turbidity measurement is a qualitative parameter for water but its traceability to a primary light scatter standard allows the measurement to be applied as a quantitative measurement. When used as a quantative measurement, turbidity is typically reported generically in turbidity units (TU’s).
Turbidity measurements are based on the instruments’ calibration with primary standard reference materials. These reference standards are traceable to formazin concentrate (normally at a value of 4000 TU). The reference concentrate is linearly diluted to provide calibration standard values. Alternative standard reference materials, such as SDVB co-polymer or stabilized formazin, are manufactured to match the formazin polymer dilutions and provide highly consistent and stable values for which to calibrate turbidity sensors.
When used for regulatory compliance reporting, specific turbidity calibration standards may be required. The user of this method should check with regulatory entities regarding specifics of allowable calibration standard materials.
The traceability to calibrations from different technologies (and other calibration standards) to primary formazin standards provides for a basis for defined turbidity units. This provides equivalence ...
SCOPE
1.1 This guide covers the best practices for use of various turbidimeter designs for measurement of turbidity in waters including: drinking water, wastewater, industrial waters and for regulatory and environmental monitoring. This guide covers both continuous and static measurements.
1.1.1 In principle there are three basic applications for on-line measurement set ups. The first is the bypass or slipstream technique a portion of sample is transported from the process or sample stream and to the turbidimeter for analysis. It is then either transported back to the sample stream or to waste. The second is the in-line measurement the sensor is submerged directly into the sample or process stream, which is typically contained in a pipe. The third is in-situ where the sensor is directly inserted into the sample stream. The in-situ principle is intended for the monitoring of water during any step within a processing train, including immediately before or after the process itself.
1.1.2 Static covers both benchtop and portable designs for the measurement of water samples that are captured into a cell and then measured.
1.2 Depending on the monitoring goals and desired data requirements, certain technologies will deliver more desirable results for a given application. This guide will help the user align a technology to a given application with respect to best practices for data collection.
1.3 Some designs are applicable for either a lower or upper measurement range. This guide will help provide guidance to the best-suited technologies based given range of turbidity.
1.4 Modern electronic turbidimeters are comprised of many parts that can cause them to produce different results on samples. The wavelength of incident light used, detector type, detector angle, number of detectors (and angles), and optical pathlength are all design criteria that may be different among instruments. When these sensors are all calibrated with...

General Information

Status
Historical
Publication Date
30-Apr-2011
ICS
17.180.30 - Optical measuring instruments
Technical Committee
D19 - Water
Drafting Committee
D19.07 - Sediments, Geomorphology, and Open-Channel Flow
Current Stage
Ref Project

Relations

Replaced By
ASTM D7726-11(2016)e1 - Standard Guide for The Use of Various Turbidimeter Technologies for Measurement of Turbidity in Water
Effective Date
01-Nov-2016
Referred By
ASTM D8002-15e1 - Standard Test Method for Modified Fouling Index (MFI-0.45) of Water
Effective Date
01-May-2011
Referred By
ASTM D5978/D5978M-16 - Standard Guide for Maintenance and Rehabilitation of Groundwater Monitoring Wells
Effective Date
01-May-2011

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ASTM D7726-11 - Standard Guide for The Use of Various Turbidimeter Technologies for Measurement of Turbidity in WaterASTM D7726-11 - Standard Guide for The Use of Various Turbidimeter Technologies for Measurement of Turbidity in Water
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ASTM D7726-11 - Standard Guide for The Use of Various Turbidimeter Technologies for Measurement of Turbidity in Water
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: D7726 − 11
StandardGuide for
The Use of Various Turbidimeter Technologies for
1
Measurement of Turbidity in Water
This standard is issued under the fixed designation D7726; 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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope same. However, samples comprise of completely different
matrices and may measure quite differently among these
1.1 This guide covers the best practices for use of various
different technologies.
turbidimeter designs for measurement of turbidity in waters
1.4.1 This guide does not provide calibration information
including:drinkingwater,wastewater,industrialwatersandfor
butratherwilldefertheusertotheappropriateASTMturbidity
regulatory and environmental monitoring. This guide covers
method and its calibration protocols. When calibrated on
both continuous and static measurements.
traceable primary turbidity standards, the assigned turbidity
1.1.1 In principle there are three basic applications for
units such as those used in Table 1. are equivalent. For
on-line measurement set ups. The first is the bypass or
example, a 1 NTU formazin standard is also equivalent in
slipstream technique a portion of sample is transported from
measurement magnitude toa1FNU,a1FAU,anda1BU
the process or sample stream and to the turbidimeter for
standard and so forth.
analysis. It is then either transported back to the sample stream
1.4.2 Improved traceability beyond the scope of this guide
or to waste. The second is the in-line measurement the sensor
maybepracticedandwouldincludethelistingofthemakeand
is submerged directly into the sample or process stream, which
modelnumberoftheinstrumentusedtodeterminetheturbidity
is typically contained in a pipe. The third is in-situ where the
values.
sensor is directly inserted into the sample stream. The in-situ
principle is intended for the monitoring of water during any 1.5 This guide does not purport to cover all available
step within a processing train, including immediately before or technologies for high-level turbidity measurement.
after the process itself.
1.6 The values stated in SI units are to be regarded as the
1.1.2 Static covers both benchtop and portable designs for
standard. The values given in parentheses are for information
the measurement of water samples that are captured into a cell
only.
and then measured.
1.7 This standard does not purport to address all of the
1.2 Depending on the monitoring goals and desired data
safety concerns, if any, associated with its use. It is the
requirements, certain technologies will deliver more desirable
responsibility of the user of this standard to establish appro-
results for a given application. This guide will help the user
priate safety and health practices and determine the applica-
align a technology to a given application with respect to best
bility of regulatory limitations prior to use.
practices for data collection.
1.8 This guide does not purport to address all of the safety
concerns, if any, associated with its use. It is the responsibility
1.3 Some designs are applicable for either a lower or upper
of the user of this standard to establish appropriate safety and
measurement range. This guide will help provide guidance to
health practices and determine the applicability of regulatory
the best-suited technologies based given range of turbidity.
limitations prior to use. Refer to the MSDSs for all chemicals
1.4 Modern electronic turbidimeters are comprised of many
used in this procedure.
parts that can cause them to produce different results on
samples. The wavelength of incident light used, detector type,
2. Referenced Documents
detector angle, number of detectors (and angles), and optical
2
2.1 ASTM Standards:
pathlength are all design criteria that may be different among
D1129 Terminology Relating to Water
instruments. When these sensors are all calibrated with the
D3977 Test Methods for Determining Sediment Concentra-
sample turbidity standards, they will all read the standards the
tion in Water Samples
1
This guide is under the jurisdiction of ASTM Committee D19 on Water and is
2
the direct responsibility of Subcommittee D19.07 on Sediments, Geomorphology, For referenced ASTM standards, visit the ASTM website, www.astm.org, or
and Open-Channel Flow. contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Current edition approved May 1, 2011. Published May 2011. DOI: 10.1520/ Standards volume information, refer to the standard’s Document Summary page on
D7726–11. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshoh
...

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ASTM D7726-11(2023)(Guide)
Standard Guide for The Use of Various Turbidimeter Technologies for Measurement of Turbidity in Water

SIGNIFICANCE AND USE
5.1 Turbidity is a measure of scattered light that results from the interaction between a beam of light and particulate material in a liquid sample. Particulate material is typically undesirable in water from a health perspective and its removal is often required when the water is intended for consumption. Thus, turbidity has been used as a key indicator for water quality to assess the health and quality of environmental water sources. Higher turbidity values are typically associated with poorer water quality.  
5.1.1 Turbidity is also used in environmental monitoring to assess the health and stability of water-based ecosystems such as in lakes, rivers and streams. In general, the lower the turbidity, the healthier the ecosystem.  
5.2 Turbidity measurement is a qualitative parameter for water but its traceability to a primary light scatter standard allows the measurement to be applied as a quantitative measurement. When used as a quantative measurement, turbidity is typically reported generically in turbidity units (TUs).  
5.2.1 Turbidity measurements are based on the instruments’ calibration with primary standard reference materials. These reference standards are traceable to formazin concentrate (normally at a value of 4000 TU). The reference concentrate is linearly diluted to provide calibration standard values. Alternative standard reference materials, such as SDVB co-polymer or stabilized formazin, are manufactured to match the formazin polymer dilutions and provide highly consistent and stable values for which to calibrate turbidity sensors.
5.2.1.1 When used for regulatory compliance reporting, specific turbidity calibration standards may be required. The user of this guide should check with regulatory entities regarding specifics of allowable calibration standard materials.  
5.2.2 The traceability to calibrations from different technologies (and other calibration standards) to primary formazin standards provides for a basis for defined turbidity uni...
SCOPE
1.1 This guide covers the best practices for use of various turbidimeter designs for measurement of turbidity in waters including: drinking water, wastewater, industrial waters, and for regulatory and environmental monitoring. This guide covers both continuous and static measurements.  
1.1.1 In principle there are three basic applications for on-line measurement set ups. The first is the bypass or slipstream technique; a portion of sample is transported from the process or sample stream and to the turbidimeter for analysis. It is then either transported back to the sample stream or to waste. The second is the in-line measurement; the sensor is submerged directly into the sample or process stream, which is typically contained in a pipe. The third is in-situ where the sensor is directly inserted into the sample stream. The in-situ principle is intended for the monitoring of water during any step within a processing train, including immediately before or after the process itself.  
1.1.2 Static covers both benchtop and portable designs for the measurement of water samples that are captured into a cell and then measured.  
1.2 Depending on the monitoring goals and desired data requirements, certain technologies will deliver more desirable results for a given application. This guide will help the user align a technology to a given application with respect to best practices for data collection.  
1.3 Some designs are applicable for either a lower or upper measurement range. This guide will help provide guidance to the best-suited technologies based given range of turbidity.  
1.4 Modern electronic turbidimeters are comprised of many parts that can cause them to produce different results on samples. The wavelength of incident light used, detector type, detector angle, number of detectors (and angles), and optical pathlength are all design criteria that may be different among instruments. When these sensors are all calibra...

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ASTM D7726-11(2023)(Guide)
Standard Guide for The Use of Various Turbidimeter Technologies for Measurement of Turbidity in Water

SIGNIFICANCE AND USE
5.1 Turbidity is a measure of scattered light that results from the interaction between a beam of light and particulate material in a liquid sample. Particulate material is typically undesirable in water from a health perspective and its removal is often required when the water is intended for consumption. Thus, turbidity has been used as a key indicator for water quality to assess the health and quality of environmental water sources. Higher turbidity values are typically associated with poorer water quality.  
5.1.1 Turbidity is also used in environmental monitoring to assess the health and stability of water-based ecosystems such as in lakes, rivers and streams. In general, the lower the turbidity, the healthier the ecosystem.  
5.2 Turbidity measurement is a qualitative parameter for water but its traceability to a primary light scatter standard allows the measurement to be applied as a quantitative measurement. When used as a quantative measurement, turbidity is typically reported generically in turbidity units (TUs).  
5.2.1 Turbidity measurements are based on the instruments’ calibration with primary standard reference materials. These reference standards are traceable to formazin concentrate (normally at a value of 4000 TU). The reference concentrate is linearly diluted to provide calibration standard values. Alternative standard reference materials, such as SDVB co-polymer or stabilized formazin, are manufactured to match the formazin polymer dilutions and provide highly consistent and stable values for which to calibrate turbidity sensors.
5.2.1.1 When used for regulatory compliance reporting, specific turbidity calibration standards may be required. The user of this guide should check with regulatory entities regarding specifics of allowable calibration standard materials.  
5.2.2 The traceability to calibrations from different technologies (and other calibration standards) to primary formazin standards provides for a basis for defined turbidity uni...
SCOPE
1.1 This guide covers the best practices for use of various turbidimeter designs for measurement of turbidity in waters including: drinking water, wastewater, industrial waters, and for regulatory and environmental monitoring. This guide covers both continuous and static measurements.  
1.1.1 In principle there are three basic applications for on-line measurement set ups. The first is the bypass or slipstream technique; a portion of sample is transported from the process or sample stream and to the turbidimeter for analysis. It is then either transported back to the sample stream or to waste. The second is the in-line measurement; the sensor is submerged directly into the sample or process stream, which is typically contained in a pipe. The third is in-situ where the sensor is directly inserted into the sample stream. The in-situ principle is intended for the monitoring of water during any step within a processing train, including immediately before or after the process itself.  
1.1.2 Static covers both benchtop and portable designs for the measurement of water samples that are captured into a cell and then measured.  
1.2 Depending on the monitoring goals and desired data requirements, certain technologies will deliver more desirable results for a given application. This guide will help the user align a technology to a given application with respect to best practices for data collection.  
1.3 Some designs are applicable for either a lower or upper measurement range. This guide will help provide guidance to the best-suited technologies based given range of turbidity.  
1.4 Modern electronic turbidimeters are comprised of many parts that can cause them to produce different results on samples. The wavelength of incident light used, detector type, detector angle, number of detectors (and angles), and optical pathlength are all design criteria that may be different among instruments. When these sensors are all calibra...

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ASTM D3321-19(2023)(Test Method)
Standard Test Method for Use of the Refractometer for Field Test Determination of the Freezing Point of Aqueous Engine Coolants

SIGNIFICANCE AND USE
4.1 This practice is commonly used by vehicle service personnel to determine the freezing point, in degrees Celsius or Fahrenheit, of aqueous solutions of commercial ethylene and propylene glycol-based coolant. A durable hand-held refractometer is available that reads the freezing point, directly, in degrees Celsius or Fahrenheit, when a few drops of engine coolant are properly placed on the temperature-compensated prism surface of the refractometer. This refractometer is for glycol and water solutions, and is not suitable for other coolant solutions.  
4.2 The hand-held refractometer should be calibrated before use (see Section 7).  
4.3 Care must be taken to use the correct glycol freezing point scale for the glycol type being measured. Use of the wrong glycol scale can result in freezing point errors of 18 and more degrees Fahrenheit.  
4.4 Ethylene glycol/propylene glycol mixtures will result in inaccurate freezing point measurements using either freezing point scale.
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1.1 This test method covers the use of a portable refractometer for determining the approximate freezing protection provided by ethylene and propylene glycol-based coolant solutions as used in engine cooling systems and special applications.  
Note 1: Some instruments have a supplementary freezing protection scale for methoxypropanol coolants. Others carry a supplemental scale calibrated in density or specific gravity readings of sulfuric acid solutions so that the refractometer can be used to determine the charged condition of lead acid storage batteries.  
1.2 The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for information only and are not considered standard.  
1.3 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.  
1.4 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.

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ASTM E3143-18b(2023)(Practice)
Standard Practice for Performing Cryo-Transmission Electron Microscopy of Liposomes

SIGNIFICANCE AND USE
5.1 Cryo-TEM is a technique used to record high resolution images of samples that are frozen and embedded in a thin layer of vitrified, amorphous ice (2-5). Because vitrification occurs so rapidly, the resultant specimen is almost instantly frozen, yielding a very accurate representation of the specimen at the moment of freezing, without the distortions typically associated with air drying delicate wet samples. Once frozen, images of the specimen are recorded at low temperature using a specially designed electron microscope equipped with a cryo-holder capable of operating under low dose conditions in order to prevent beam induced structural damage to the specimen. The cryo-TEM technique is the consensus choice to directly observe, analyze and accurately measure liposomes suspended in aqueous solutions. Fig. 1 illustrates this by comparing an electron micrograph from an air-dried negatively stained liposomal preparation with an electron micrograph of the same solution imaged by cryo-TEM.
FIG. 1 Left—An Electron Micrograph of an Air-Dried Liposomal Preparation that has been Negatively Stained with 2 % Uranyl Acetate for Contrast; Right—An Electron Micrograph of the Same Liposomal Preparation Prepared as a Frozen Vitrified Specimen for Cryo-TEM
Note 1: Both images are shown to the same scale; scale bar is 200 nm.  
5.1.1 Fig. 1 demonstrates that liposomes may become distorted and are difficult to measure and analyze when they are air-dried, while the same liposomal preparation is clearly easier to analyze when the specimen is near-instantly preserved by vitrification.  
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SCOPE
1.1 This practice covers procedures for vitrifying and recording images of a suspension of liposomes with a cryo-transmission electron microscope (cryo-TEM) for the purpose of evaluating their shape, size distribution and lamellarity for quality assessment. The sample is vitrified in liquid ethane onto specially prepared holey, ultra-thin, or continuous carbon TEM grids, and imaged in a cryo-holder placed in a cryo-TEM.  
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ASTM E2911-23(Guide)
Standard Guide for Relative Intensity Correction of Raman Spectrometers

SIGNIFICANCE AND USE
4.1 Generally, Raman spectra measured using grating-based dispersive or Fourier transform Raman spectrometers have not been corrected for the instrumental response (spectral responsivity of the detection system). Raman spectra obtained with different instruments may show significant variations in the measured relative peak intensities of a sample compound. This is mainly as a result of differences in their wavelength-dependent optical transmission and detector efficiencies. These variations can be particularly large when widely different laser excitation wavelengths are used, but can occur when the same laser excitation is used and spectra of the same compound are compared between instruments. This is illustrated in Fig. 1, which shows the uncorrected luminescence spectrum of SRM 2241, acquired upon four different commercially available Raman spectrometers operating with 785 nm laser excitation. Instrumental response variations can also occur on the same instrument after a component change or service work has been performed. Each spectrometer, due to its unique combination of filters, grating, collection optics and detector response, has a very unique spectral response. The spectrometer dependent spectral response will of course also affect the shape of Raman spectra acquired upon these systems. The shape of this response is not to be construed as either “good or bad” but is the result of design considerations by the spectrometer manufacturer. For instance, as shown in Fig. 1, spectral coverage can vary considerably between spectrometer systems. This is typically a deliberate tradeoff in spectrometer design, where spectral coverage is sacrificed for enhanced spectral resolution.
FIG. 1 SRM 2241 Measured on Four Commercial Raman Spectrometers Utilizing 785 nm Excitation  
4.2 Variations in spectral peak intensities can be mostly corrected through calibration of the Raman intensity (y) axis. The conventional method of calibration of the spectral response of a Raman...
SCOPE
1.1 This guide is designed to enable the user to correct a Raman spectrometer for its relative spectral-intensity response function using NIST Standard Reference Materials2 in the 224X series (currently SRMs 2241, 2242, 2243, 2244, 2245, 2246), or a calibrated irradiance source. This relative intensity correction procedure will enable the intercomparison of Raman spectra acquired from differing instruments, excitation wavelengths, and laboratories.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 Because of the significant dangers associated with the use of lasers, ANSI Z136.1 or suitable regional standards should be followed in conjunction with this practice.  
1.4 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.  
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ASTM E520-08(2023)(Practice)
Standard Practice for Describing Photomultiplier Detectors in Emission and Absorption Spectrometry

ABSTRACT
This practice describes the photomultiplier properties that are essential to their judicious selection and use of in emission and absorption spectrometry. The properties covered here include structural features, electrical properties, and characteristics involved in precautions and problems. The structural features covered are envelope configurations, window materials, electrical connections, and housing for the external structure, and the photocathode, dynodes and anode, and rigidness of structural components for the internal structure. Electrical properties, on the other hand, incorporate the following: optical-electronic characteristics of the photocathode including spectral response; current amplification including gain per stage, overall gain, gain control (voltage-divider bridge), linearity of response, and anode saturation; signal nature; dark current including cathode size, internal aperture, and refrigeration effects; noise nature including additivity of noise power, signal-to-noise ratio, equivalent noise input; and photomultiplier properties as a component in an electrical circuit including output impedance, response time, and signal gating and integration possibilities. Finally, the characteristics involved in precautions and problems cover fatigue and hysteresis effects, illumination of photocathode, and gas leakage.
SCOPE
1.1 This practice covers photomultiplier properties that are essential to their judicious selection and use in emission and absorption spectrometry. Descriptions of these properties can be found in the following sections:    
Section  
Structural Features  
4  
General  
4.1  
External Structure  
4.2  
Internal Structure  
4.3  
Electrical Properties  
5  
General  
5.1  
Optical-Electronic Characteristics of the Photocathode  
5.2  
Current Amplification  
5.3  
Signal Nature  
5.4  
Dark Current  
5.5  
Noise Nature  
5.6  
Photomultiplier as a Component in an Electrical Circuit  
5.7  
Precautions and Problems  
6  
General  
6.1  
Fatigue and Hysteresis Effects  
6.2  
Illumination of Photocathode  
6.3  
Gas Leakage  
6.4  
Recommendations on Important Selection Criteria  
7  
1.2 Radiation in the frequency range common to analytical emission and absorption spectrometry is detected by photomultipliers presently to the exclusion of most other transducers. Detection limits, analytical sensitivity, and accuracy depend on the characteristics of these current-amplifying detectors as well as other factors in the system.  
1.3 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.  
1.4 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.

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ASTM E388-04(2023)(Test Method)
Standard Test Method for Wavelength Accuracy and Spectral Bandwidth of Fluorescence Spectrometers

ABSTRACT
This test method covers the testing of the spectral bandwidth and wavelength accuracy of fluorescence spectrometers that use a monochromator for emission wavelength selection and photomultiplier tube detection. The method can be applied to instruments that use multi-element detectors, such as diode arrays, but results must be interpreted carefully. Atomic lines between 250 nm and 1000 nm are used in the method. The difference between the apparent wavelength and the known wavelength for a series of atomic emission lines is used as a test for wavelength accuracy. The apparent width of some of these lines is used as a test for spectral bandwidth.
SCOPE
1.1 This test method covers the testing of the spectral bandwidth and wavelength accuracy of fluorescence spectrometers that use a monochromator for emission wavelength selection and photomultiplier tube detection. This test method can be applied to instruments that use multi-element detectors, such as diode arrays, but results must be interpreted carefully. This test method uses atomic lines between 250 nm and 1000 nm.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 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.  
1.4 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.

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ASTM E1840-96(2022)(Guide)
Standard Guide for Raman Shift Standards for Spectrometer Calibration

SIGNIFICANCE AND USE
4.1 Wavenumber calibration is an important part of Raman analysis. The calibration of a Raman spectrometer is performed or checked frequently in the course of normal operation and even more often when working at high resolution. To date, the most common source of wavenumber values is either emission lines from low-pressure discharge lamps (for example, mercury, argon, or neon) or from the non-lasing plasma lines of the laser. There are several good compilations of these well-established values (1-8).3 The disadvantages of using emission lines are that it can be difficult to align lamps properly in the sample position and the laser wavelength must be known accurately. With argon, krypton, and other ion lasers commonly used for Raman the latter is not a problem because lasing wavelengths are well known. With the advent of diode lasers and other wavelength-tunable lasers, it is now often the case that the exact laser wavelength is not known and may be difficult or time-consuming to determine. In these situations it is more convenient to use samples of known relative wavenumber shift for calibration. Unfortunately, accurate wavenumber shifts have been established for only a few chemicals. This guide provides the Raman spectroscopist with average shift values determined in seven laboratories for seven pure compounds and one liquid mixture.
SCOPE
1.1 This guide covers Raman shift values for common liquid and solid chemicals that can be used for wavenumber calibration of Raman spectrometers. The guide does not include procedures for calibrating Raman instruments. Instead, this guide provides reliable Raman shift values that can be used as a complement to low-pressure arc lamp emission lines which have been established with a high degree of accuracy and precision.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 Some of the chemicals specified in this guide may be hazardous. It is the responsibility of the user of this guide to consult material safety data sheets and other pertinent information to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to their use.  
1.4 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.  
1.5 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.

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ASTM E1172-22(Practice)
Standard Practice for Describing and Specifying a Wavelength Dispersive X-Ray Spectrometer

SIGNIFICANCE AND USE
4.1 This practice describes the essential components of a wavelength dispersive X-ray spectrometer. This description is presented so that the user may gain a general understanding of the structure of an X-ray spectrometer system. It also provides a means for comparing and evaluating different systems as well as understanding the capabilities and limitations of each instrument.  
4.2 A laboratory may implement this practice or an X-ray fluorescence method in partnership with a manufacturer of the analytical instrumentation. If a laboratory chooses to consult with an instrument manufacturer, then the following should be considered. The laboratory should know the alloy matrices to be analyzed, elements and mass fraction ranges to be determined, and the expected performance requirements for each of these elements. The laboratory should inform the instrument manufacturer of these requirements so an analytical method may be developed which meets the laboratory’s expectations. Typically, instrument manufacturers customize the instrument configuration to satisfy the end-user’s requirements for elemental coverage, elemental precision, and detection limits. Instrument manufacturer developed analytical methods may include specific parameters for sample excitation, wavelengths, inter-element interference corrections, calibration and regression, equipment configuration/installation, and sample preparation requirements. Laboratories should have a basic understanding of the parameters derived by the manufacturer.
SCOPE
1.1 This practice covers the components of a wavelength dispersive X-ray spectrometer that are basic to its operation and to the quality of its performance. It is not the intent of this practice to specify component tolerances or performance criteria, as these are unique for each instrument. However, the practice does attempt to identify which tolerances are critical and thus which should be specified.  
1.2 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. Specific safety hazard statements are given in Section 7.  
1.3 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.

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ASTM
ASTM E387-04(2022)(Test Method)
Standard Test Method for Estimating Stray Radiant Power Ratio of Dispersive Spectrophotometers by the Opaque Filter Method

SIGNIFICANCE AND USE
5.1 Stray radiant power can be a significant source of error in spectrophotometric measurements. SRP usually increases with the passage of time; therefore, testing should be performed periodically. Moreover, the SRPR test is an excellent indicator of the overall condition of a spectrophotometer. A control-chart record of the results of routinely performed SRPR tests can be a useful indicator of need for corrective action or, at least, of the changing reliability of critical measurements.  
5.2 This test method provides a means of determining the stray radiant power ratio of a spectrophotometer at selected wavelengths in a spectral range, as determined by the SRP filter used, thereby revealing those wavelength regions where significant photometric errors might occur. It does not provide a means of calculating corrections to indicated absorbance (or transmittance) values. The test method must be used with care and understanding, as erroneous results can occur, especially with respect to some modern grating instruments that incorporate moderately narrow bandpass SRP-blocking filters. This test method does not provide a basis for comparing the performance of different spectrophotometers.
Note 8: Kaye (3) discusses correction methods of measured transmittances (absorbances) that sometimes can be used if sufficient information on the properties and performance of the instrument can be acquired. See also A1.2.5.  
5.3 This test method describes the performance of a spectrophotometer in terms of the specific test parameters used. When an analytical sample is measured, absorption by the sample of radiation outside of the nominal bandpass at the analytical wavelength can cause a photometric error, underestimating the transmittance or overestimating the absorbance, and correspondingly underestimating the SRPR.  
5.4 The SRPR indicated by this test method using SRP filters is almost always an underestimation of the true value (see 1.3). A value cited in a manufacturer’s li...
SCOPE
1.1 Stray radiant power (SRP) can be a significant source of error in spectrophotometric measurements, and the danger that such error exists is enhanced because its presence often is not suspected (1-4).2 This test method affords an estimate of the relative radiant power, that is, the Stray Radiant Power Ratio (SRPR), at wavelengths remote from those of the nominal bandpass transmitted through the monochromator of an absorption spectrophotometer. Test-filter materials are described that discriminate between the desired wavelengths and those that contribute most to SRP for conventional commercial spectrophotometers used in the ultraviolet, the visible, the near infrared, and the mid-infrared ranges. These procedures apply to instruments of conventional design, with usual sources, detectors, including array detectors, and optical arrangements. The vacuum ultraviolet and the far infrared present special problems that are not discussed herein.
Note 1: Research (3) has shown that particular care must be exercised in testing grating spectrophotometers that use moderately narrow bandpass SRP-blocking filters. Accurate calibration of the wavelength scale is critical when testing such instruments. Refer to Practice E275.  
1.2 These procedures are neither all-inclusive nor infallible. Because of the nature of readily available filter materials, with a few exceptions, the procedures are insensitive to SRP of very short wavelengths in the ultraviolet, or of lower frequencies in the infrared. Sharp cutoff longpass filters are available for testing for shorter wavelength SRP in the visible and the near infrared, and sharp cutoff shortpass filters are available for testing at longer visible wavelengths. The procedures are not necessarily valid for “spike” SRP nor for “nearby SRP.” (See Annexes for general discussion and definitions of these terms.) However, they are adequate in most cases and for typical applications. They do cover...

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