5.1 Benzene is a compound that endangers health, and the concentration is limited by environmental protection agencies to produce a less toxic gasoline.5.2 This test method is fast, simple to run, and inexpensive.5.3 This test method is applicable for quality control in the production and distribution of spark-ignition engine fuels.1.1 This test method covers the determination of the percentage of benzene in spark-ignition engine fuels. It is applicable to concentrations from 0.1 % to 5 % by volume.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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5.1 This test method provides a means for obtaining useful in-service fluid analysis properties in the field. It is not to be confused with laboratory or portable FTIR devices which provide measurements per the existing Test Methods listed in 4.1.1.1. Each of these monitored properties has been shown over time to indicate either contamination in the fluid system or a particular breakdown modality of the fluid, which is critical information to assess the health of the fluid as well as the machinery. By utilizing the field device, it is possible for those operating machinery, in locations and situations where it is not practical to gather a sample for the laboratory, to obtain quality in-service fluid analysis. This may be due to the need to have an analysis done in real-time, on-the-spot to maximize the operational hours of equipment, or to have the analysis performed at a location where no laboratory analysis is available.1.1 This test method describes the use of a grating spectrometer to analyze properties of an in-service fluid sample which are indicative of the status of that fluid and related machinery.1.2 This test method provides a means for the assessment of in-service fluid properties using infrared spectroscopy. It describes a methodology for sampling, performing analysis, and providing key in-service fluid properties with a self-contained unit that is meant for field use. It provides analysis of in-service fluids at any stage of their useful life, including newly utilized fluid.1.3 In particular, these key in-service fluid properties include oxidation, nitration, sulfation, soot, and antiwear additives. They are applicable for hydrocarbon type (API Group I-IV) fluids from machinery lubricants, including reciprocating engine oils, turbine oils, hydraulic oils, and gear oils.1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.4.1 Exception—The unit for wavenumbers is in cm-1.1.5 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.

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4.1 The composition and sequential structure of alginate determines the functionality of alginate in an application. For instance, the gelling properties of an alginate are highly dependent upon the monomer composition and sequential structure of the polymer. Gel strength will depend upon the guluronic acid content (FG) and also the average number of consecutive guluronate moieties in G-block structures (NG>1).4.2 Chemical composition and sequential structure of alginate can be determined by 1H- and 13C-nuclear magnetic resonance spectroscopy (NMR). A general description of NMR can be found in <761> of the USP 35-NF30. The NMR methodology and assignments are based on data published by Grasdalen et al. (1979, 1981, 1983).4, 5, 6 The NMR technique has made it possible to determine the monad frequencies FM (fraction of mannuronate units) and FG (fraction of guluronate units), the four nearest neighboring (diad) frequencies FGG, FMG, FGM, FMM, and the eight next nearest neighboring (triad) frequencies FGGG, FGGM, FMGG, FMGM, FMMM, FMMG, FGMM, FGMG. Knowledge of these frequencies enables number averages of block lengths to be calculated. NG is the number average length of G-blocks, and NG>1 is the number average length of G-blocks from which singlets (-MGM-) have been excluded. Similarly, NM is the number average length of M-blocks, and NM>1 is the number average length of M-blocks from which singlets (-GMG-) have been excluded. 13C NMR must be used to determine the M-centered triads and NM>1. This test method describes only the 1H NMR analysis of alginate. Alginate can be well characterized by determining FG and NG>1.4.3 In order to obtain well-resolved NMR spectra, it is necessary to reduce the viscosity and increase the mobility of the molecules by depolymerization of alginate to a degree of polymerization of about 20 to 50. Acid hydrolysis is used to depolymerize the alginate samples. Freeze-drying, followed by dissolution in 99 % D2O, and another freeze-drying before dissolution in 99.9 % D2O yields samples with low 1H2O content. TTHA is used as a chelator to prevent traces of divalent cations to interact with alginate. While TTHA is a more effective chelator, other agents such as EDTA and citrate may be used. Such interactions may lead to line broadening and selective loss of signal intensity.4.4 Samples are analyzed at a temperature of 80 ± 1°C. Elevated sample temperature contributes to reducing sample viscosity and repositions the proton signal of residual water to an area outside that of interest.1.1 This test method covers the determination of the composition and monomer sequence of alginate intended for use in biomedical and pharmaceutical applications as well as in Tissue Engineered Medical Products (TEMPs) by high-resolution proton NMR (1H NMR). A guide for the characterization of alginate has been published as Guide F2064.1.2 Alginate, a linear polymer composed of β-D-mannuronate (M) and its C-5 epimer α-L-guluronate (G) linked by β-(1—>4) glycosidic bonds, is characterized by calculating parameters such as mannuronate/guluronate (M/G) ratio, guluronic acid content (G-content), and average length of blocks of consecutive G monomers (that is, NG>1 ). Knowledge of these parameters is important for an understanding of the functionality of alginate in TEMP formulations and applications. This test method will assist end users in choosing the correct alginate for their particular application. Alginate may have utility as a scaffold or matrix material for TEMPs, in cell and tissue encapsulation applications, and in drug delivery formulations.1.3 The values stated in SI units are to be regarded as standard. No other units 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 responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

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4.1 The degree of deacetylation of chitosan salts is an important characterization parameter since the charge density of the chitosan molecule is responsible for potential biological and functional effects.4.2 The degree of deacetylation (% DDA) of water-soluble chitosan salts can be determined by 1H nuclear magnetic resonance spectroscopy (1H NMR). Several workers have reported on the NMR determination of chemical composition and sequential arrangement of monomer units in chitin and chitosan. The test method described is primarily based on the work of Vårum et al. (1991),5 which represents the first publication on routine determination of chemical composition in chitosans by solution state 1H NMR spectroscopy. This test method is applicable for determining the % DDA of chitosan chloride and chitosan glutamate salts. It is a simple, rapid, and suitable method for routine use. Quantitative 1H NMR spectroscopy reports directly on the relative concentration of chemically distinct protons in the sample, consequently, no assumptions, calibration curves or calculations other than determination of relative signal intensity ratios are necessary.4.3 In order to obtain well-resolved NMR spectra, depolymerization of chitosans to a number average degree of polymerization (DPn) of ~15 to 30 is required. This reduces the viscosity and increases the mobility of the molecules. Although there are several options for depolymerization of chitosans, the most convenient procedure is that of nitrous acid degradation in deuterated water. The reaction is selective, stoichiometric with respect to GlcN, rapid, and easily controlled (Allan & Peyron, 1995).6 The reaction selectively cleaves after a GlcN-residue, transforming it into 2,5-anhydro-D-mannose (chitose), consequently, depletion of GlcN after depolymerization is expected. On the other hand, the chitose unit displays characteristic 1H NMR signals the intensity of which may be estimated and utilized in the calculation of % DDA, eliminating the need for correction factors. Using the intensity of the chitose signals, the number average degree of polymerization can easily be calculated as a control of the depolymerization.4.4 Samples are equilibrated and analyzed at a temperature of 90 ± 1°C. Elevated sample temperature contributes to reducing sample viscosity and repositions the proton signal of residual water to an area outside that of interest. While samples are not stored at 90°C but only analyzed at this elevated temperature, the NMR tubes should be sealed with a stopper to avoid any evaporation. At a sample pH* of 3.8-4.3 (see 6.1.5 below), artifactual deacetylation of the sample does not occur during the short equilibration and analysis time.4.5 A general description of NMR can be found in <761> of the USP 35-NF30.1.1 This test method covers the determination of the degree of deacetylation in chitosan and chitosan salts intended for use in biomedical and pharmaceutical applications as well as in Tissue Engineered Medical Products (TEMPs) by high-resolution proton NMR (1H NMR). A guide for the characterization of chitosan salts has been published as Guide F2103.1.2 The test method is applicable for determining the degree of deacetylation (% DDA) of chitosan chloride and chitosan glutamate salts and is valid for % DDA values from 50 up to and including 99. It is simple, rapid, and suitable for routine use. Knowledge of the degree of deacetylation is important for an understanding of the functionality of chitosan salts in TEMP formulations and applications. This test method will assist end users in choosing the correct chitosan for their particular application. Chitosan salts may have utility in drug delivery applications, as scaffold or matrix material, and in cell and tissue encapsulation applications.1.3 The values stated in SI units are to be regarded as standard. No other units 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 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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This guide presents the use of spectral searching by curve matching search algorithms for data recorded using mid-infrared spectroscopy. The methods described herein may be applicable to the use of these algorithms for other types of spectroscopic data, but each type of data search should be assessed separately. The purpose of this evaluation is the classification and, where possible, identification of the unknown. Spectral searching is intended as a screening method to assist the analyst, and is not an absolute identification technique, and hence, not intended to replace an expert in infrared spectroscopy and should not be used without suitable training. The Euclidean distance algorithm and the first derivative Euclidean distance algorithm are described and their use discussed. The theory and common assumptions made when using search algorithms are also discussed, along with guidelines for the use and interpretation of the search results.1.1 Spectral searching is the process whereby a spectrum of an unknown material is evaluated against a library (database) of digitally recorded reference spectra. The purpose of this evaluation is classification of the unknown and, where possible, identification of the unknown. Spectral searching is intended as a screening method to assist the analyst and is not an absolute identification technique. Spectral searching is not intended to replace an expert in infrared spectroscopy. Spectral searching should not be used without suitable training.1.2 The user of this guide should be aware that the results of a spectral search can be affected by the following factors described in Section 5: (1) baselines, (2) sample purity, (3) Absorbance linearity (Beer’s Law), (4) sample thickness, (5) sample technique and preparation, (6) physical state of the sample, (7) wavenumber range, (8) spectral resolution, and (9) choice of algorithm.1.2.1 Many other factors can affect spectral searching results.1.3 The scope of this guide is to provide a guide for the use of search algorithms for mid-infrared spectroscopy. The methods described herein may be applicable to the use of these algorithms for other types of spectroscopic data, but each type of data search should be assessed separately.1.4 The Euclidean distance algorithm and the first derivative Euclidean distance algorithm are described and their use discussed. The theory and common assumptions made when using search algorithms are also discussed, along with guidelines for the use and interpretation of the search results.1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

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5.1 Knowledge of the presence of trace metals in gas turbine fuels enables the user to predict performance and, when necessary, to take appropriate action to prevent corrosion.1.1 This test method covers the determination of sodium, lead, calcium, and vanadium in Specification D2880 Grade Nos. 0-GT through 4-GT fuels at 0.5 mg/kg level for each of the elements. This test method is intended for the determination of oil-soluble metals and not waterborne contaminants in oil-water mixtures.1.1.1 Test Method D6728 is suggested as an alternative test method for the determination of these elements in Specification D2880.1.2 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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5.1 Moisture measurement in natural gas is performed to ensure sufficiently low levels for gas purchase contracts and to prevent corrosion. Moisture may also contribute to the formation of hydrates.5.2 The significance of applying TDLAS for the measurement of moisture in natural gas is TDLAS analyzers may have a very high degree of selectivity and minimal interference in many natural gas streams. Additionally, the sensing components of the analyzer are not wetted by the natural gas, limiting the potential damage from corrosives such as hydrogen sulfide (H2S) and liquid contaminants such as ethylene glycol or compressor oils. As a result, the TDLAS analyzer is able to detect changes in concentration with relatively rapid response. It should be noted that the mirrors of a TDLAS analyzer may be fouled if large quantities of condensed liquids enter the sample cell. In most cases the mirror can be cleaned without the need for recalibration or realignment.5.3 Primary applications covered in this method are listed in 5.3.1 – 5.3.3. Each application may have differing requirements and methods for gas sampling. Additionally, different natural gas applications may have unique spectroscopic considerations.5.3.1 Raw natural gas is found in production, gathering sites, and inlets to gas-processing plants characterized by potentially high levels of water (H2O), carbon dioxide (CO2), hydrogen sulfide (H2S), and heavy hydrocarbons. Gas-conditioning plants and skids are normally used to remove H2O, CO2, H2S, and other contaminants. Typical moisture concentration after dehydration is roughly 20 to 200 ppmv. Protection from liquid carryover such as heavy hydrocarbons and glycols in the sample lines is necessary to prevent liquid pooling in the cell or the sample components.5.3.2 Underground gas storage facilities are high-pressure caverns used to store large volumes of gas for use during peak demand. Underground storage caverns can reach pressures as high as 275 bar. Multistage and heated regulator systems are usually required to overcome significant temperature drops resulting from gas expansion in the sample.5.3.3 High-quality “sales gas” is found in transportation pipelines, natural gas distribution (utilities), and natural gas power plant inlets. The gas is characterized by a very high percentage of methane (90 to 100 %) with small quantities of other hydrocarbons and trace levels of contaminates.1.1 This test method covers online determination of vapor phase moisture concentration in natural gas using a tunable diode laser absorption spectroscopy (TDLAS) analyzer also known as a “TDL analyzer.” The particular wavelength for moisture measurement varies by manufacturer; typically between 1000 and 10 000 nm with an individual laser having a tunable range of less than 10 nm.1.2 Process stream pressures can range from 700-mbar to 700-bar gage. TDLAS is performed at pressures near atmospheric (700- to 2000-mbar gage); therefore, pressure reduction is typically required. TDLAS can be performed in vacuum conditions with good results; however, the sample conditioning requirements are different because of higher complexity and a tendency for moisture ingress and are not covered by this test method. Generally speaking, the vent line of a TDL analyzer is tolerant to small pressure changes on the order of 50 to 200 mbar, but it is important to observe the manufacturer’s published inlet pressure and vent pressure constraints. Large spikes or steps in backpressure may affect the analyzer readings.1.3 The typical sample temperature range is -20 to 65 °C in the analyzer cell. While sample system design is not covered by this standard, it is common practice to heat the sample transport line to around 50 °C to avoid concentration changes associated with adsorption and desorption of moisture along the walls of the sample transport line.1.4 The moisture concentration range is 1 to 10 000 parts per million by volume (ppmv). It is unlikely that one spectrometer cell will be used to measure this entire range. For example, a TDL spectrometer may have a maximum measurement of 1 ppmv, 100 ppmv, 1000 ppmv, or 10 000 ppmv with varying degrees of accuracy and different lower detection limits.1.5 TDL absorption spectroscopy measures molar ratios such as ppmv or mole percentage. Volumetric ratios (ppmv and %) are not pressure dependent. Weight-per-volume units such as milligrams of water per standard cubic metre or pounds of water per standard cubic foot can be derived from ppmv at a specific condition such as standard temperature and pressure (STP). Standard conditions may be defined differently for different regions and entities. The dew point can be estimated from ppmv and pressure. Refer to Test Method D1142 and ISO 18453.1.6 Units—The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.7 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. Some specific hazards statements are given in Section 8 on Hazards.1.8 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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5.1 In many cases, equipment failure modes are identified by wear debris that is not captured in used lubricating oil samples but captured on chip detectors, filters or by other means. Users of this technique include, but are not limited to, original equipment manufacturers (OEMs), commercial airlines, civil aerospace operators, maintenance repair and overhaul (MRO) facilities, and military maintenance personnel.1.1 This test method describes a means for quantitative determination of wear debris found in in-service lubricants by laser-induced breakdown spectroscopy (LIBS). LIBS is an analytical technology that uses short laser pulses to create micro hot-plasma ablation of a material and then employs spectroscopic tools for analysis.21.2 This method covers the means for alloy classification and sizing of wear debris. Wear debris sources can include, but are not limited to: (1) chip collector and chip detector devices, (2) filters, (3) ferrograms, and (4) loose particles. The 23 tested alloys and metals included in the default material library of the instrument are listed in Table 1.1.3 The method for alloy classification and sizing of wear debris is not limited to the list of alloys in Table 1. The instrument has the capability of including additional alloys and metals as required.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.

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AbstractThese practices cover a data system comprising procedures for the identification of individual chemical substances using infrared absorption spectroscopy and band indexes of spectral data. Although this data system is in use world wide as the largest publicly available data base, it does not represent the optimum way to generate a new data base with the most modern computerized equipment. In addition, the use of these practices requires encoded data and appropriate data handling equipment. The index data, which are available on magnetic tape, include codes for spectral data of chemical substances, chemical-structure classification, empirical formula, melting or boiling point, and serial number reference. Codes on sample state, wavelength intervals of strongest bands, and no-data areas are included as well.1.1 These practices cover a data system generated from 1955 through 1974. It is in world-wide use as the largest publicly available data base. It is recognized that it does not represent the optimum way to generate a new data base with the most modern computerized equipment.1.2 These practices describe procedures for identification of individual chemical substances using infrared absorption spectroscopy and band indexes of spectral data. Use of absorption spectroscopy for qualitative analysis has been described by many (), but the rapid matching of the spectrogram of a sample with a spectral data in the literature by use of a band index system designed for machine sorting was contributed by Kuentzel (). It is on Kuentzel's system that the ASTM indexes of absorption spectral data are based.1.3 Use of these practices requires, in addition to a recording spectrometer and access to published reference spectra, the encoded data and suitable data handling equipment.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 and health practices and determine the applicability of regulatory limitations prior to use.

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5.1 This test method is intended to provide a means for determining the concentration of argon in sealed insulating glass units under controlled conditions in compliance with the apparatus manufacturer's instructions.5.2 This is a non-destructive test method in that the edge seal of the test specimen is not breached in order to determine the argon gas concentration. However, damage to some glass coatings on the inner surfaces of the glass can occur.5.3 This test method has been developed based on data collected in a controlled laboratory environment.5.4 The device shall be used to determine the argon gas concentration in insulating glass units in a controlled laboratory environment. Refer to 12.3.5.5 This test method may be used to determine the argon gas concentration before, during, or after the insulating glass unit is subjected to durability tests.5.6 The accuracy of the test method is dependent upon the accuracy of the Spark Emission Spectroscope. When the concentration of the argon being measured is below certain levels, this test method is not applicable. See the spectroscope manufacturer’s literature for recommended levels of accuracy of a given model.1.1 This test method covers procedures for using a spark emission spectroscope to determine the concentration of argon gas in the space between the lites of a sealed insulating glass unit.1.2 This is a non-destructive test method.1.3 This test method shall be used only in a controlled laboratory environment.1.4 This test method is applicable for insulating glass units where argon has been added to the sealed insulating glass cavity and the balance of the gas is atmospheric air.1.5 This test method is applicable for clear, double-glazed insulating glass units.1.6 This test method is applicable for double-glazed insulating glass units with one lite having a metallic coating or tinted glass, or both, and with clear glass as the other lite.1.7 This test method is applicable for triple-glazed insulating glass units only when the center lite of glass has a metallic coating (either low emissivity (low E) or reflective) and both of the other lites are clear glass.1.8 This test method also includes a procedure for verifying the accuracy of the readings of the test apparatus.1.9 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.1.10 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. For specific warning statements, refer to Section 7 on Hazards.1.11 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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5.1 The composition of liquefied gaseous fuels (LNG, LPG) is important for custody transfer and production. Compositional determination is used to calculate the heating value, and it is important to ensure regulatory compliance. Compositional determination is also used to optimize the efficiency of liquefied hydrocarbon gas production and ensure the quality of the processed fluids.5.2 Alternatives to compositional measurement using Raman spectroscopy are described in Test Method D1945, Practice D1946, and Test Method D7833.5.3 The advantage of this practice over other standards stated in 5.2, is that Raman spectroscopy can determine composition by directly measuring the liquefied natural gas. Unlike chromatography, no vaporization step is necessary. Since incorrect operation of on-line vaporizers can lead to poor precision and accuracy, elimination of the vaporization step offers a significant improvement in the analysis of LNG.1.1 This practice is for both on-line and laboratory instrument-based determination of composition for liquefied natural gas (LNG) using Raman spectroscopy. Although the procedures in this practice refer specifically to liquids, the basic methodology can also be applied to other light hydrocarbon mixtures in either liquid or gaseous states, provided the data quality objectives and measurement needs are met. From the composition, gas properties such as heating value and the Wobbe index may be calculated. The components commonly determined according to this test method are CH4, C2H6, C3H8, i-C4H10, n-C4H10, iC5H12, n-C5H12. Components heavier than C5 are not measured as part of this practice.NOTE 1: Raman spectroscopy does not directly quantify the component percentages of noble gases; however, inert substances can be calculated indirectly by subtracting the sum of the other species from 100 %.1.2 Units—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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5.1 Small quantities of sodium, 1 to 10 μg/L, can be significant in high pressure boiler systems and in nuclear power systems. Steam condensate from such systems must have less than 10 μg/L. In addition, condensate polishing system effluents should have less than 1 μg/L. Graphite furnace atomic absorption spectroscopy (GFAAS) represents technique for determining low concentrations of sodium.1.1 This test method covers the determination of trace sodium in high purity water. The method range of concentration is 1 to 40 μg/L sodium. The analyst may extend the range once its applicability has been ascertained.NOTE 1: It is necessary to perform replicate analysis and take an average to accurately determine values at the lower end of the stated range.1.2 This test method is a graphite furnace atomic absorption spectrophotometric method for the determination of trace sodium impurities in ultra high purity water.1.3 This test method has been used successfully with a high purity water matrix.2 It is the responsibility of the analyst to determine the suitability of the test method for other matrices.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.

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5.1 Proton exchange membranes (PEM) used in fuel cells are susceptible to contamination from a number of species that can be found in hydrogen. It is critical that these contaminants be measured and verified to be present at or below the amounts stated in SAE J2719 and ISO 14687 to ensure both fuel cell longevity and optimum efficiency. Contaminant concentrations as low as single-figure ppb(v) for some species can seriously compromise the life span and efficiency of PEM fuel cells. The presence of contaminants in fuel-cell-grade hydrogen can, in some cases, have a permanent adverse impact on fuel cell efficiency and usability. It is critical to monitor the concentration of key contaminants in hydrogen during the production phase through to delivery of the fuel to a fuel cell vehicle or other PEM fuel cell application. In ISO 14687, the upper limits for the contaminants are specified. Refer to SAE J2719 (see 2.3) for specific national and regional requirements. For hydrogen fuel that is transported and delivered as a cryogenic liquid, there is additional risk of introducing impurities during transport and delivery operations. For instance, moisture can build up over time in liquid transfer lines, critical control components, and long-term storage facilities, which can lead to ice buildup within the system and subsequent blockages that pose a safety risk or the introduction of contaminants into the gas stream upon evaporation of the liquid. Users are reminded to consult Practice D7265 for critical thermophysical properties such as the ortho/para hydrogen spin isomer inversion that can lead to additional hazards in liquid hydrogen usage.1.1 This test method describes contaminant determination in fuel cell grade hydrogen as specified in relevant ASTM and ISO standards using cavity ring-down spectroscopy (CRDS). This standard test method is for the measurement of one or multiple contaminants including, but not limited to, water (H2O), oxygen (O2), methane (CH4), carbon dioxide (CO2), carbon monoxide (CO), ammonia (NH3), and formaldehyde (H2CO), henceforth referred to as “analyte.”1.2 This test method applies to CRDS analyzers with one or multiple sensor modules (see 6.2 for definition). This test method describes sampling apparatus design, operating procedures, and quality control procedures required to obtain the stated levels of precision and accuracy.1.3 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined.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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Auger analysis is used to determine the elemental composition of the first several atomic layers, typically 1 to 5 nm thick, of a specimen surface. In conjunction with inert gas ion sputtering, it is used to determine the sputter depth profile to a depth of a few micrometres.The specimen is normally a solid conductor, semiconductor, or insulator. For insulators, provisions may be required for control of charge accumulation at the surface (see Guide E 1523). Typical applications include the analysis of surface contaminants, thin film deposits or segregated overlayers on metallic or alloy substrates. The specimen topography may vary from a smooth, polished specimen to a rough fracture surface.Auger analysis of specimens with volatile species that evaporate in the ultra-high vacuum environment of the Auger chamber and substances which are susceptible to electron or X-ray beam damage, such as organic compounds, may require special techniques not covered herein. (See Guide E 983.)1.1 This practice outlines the necessary steps for the identification of elements in a given Auger spectrum obtained using conventional electron spectrometers. Spectra displayed as either the electron energy distribution (direct spectrum) or the first derivative of the electron energy distribution are considered.1.2 This practice applies to Auger spectra generated by electron or X-ray bombardment of the specimen surface and can be extended to spectra generated by other methods such as ion bombardment.1.3 The values stated in SI units are to be regarded as standard. No other units 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 responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

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