4.1 The composition and sequential structure of alginate, as well as the molar mass and molar mass distribution, determines the functionality of alginate in an application. For instance, the gelling properties of an alginate are highly dependent upon the composition and molar mass of the polymer.4.2 Light scattering is one of very few methods available for the determination of absolute molar mass and structure, and it is applicable over the broadest range of molar masses of any method. Combining light scattering detection with size exclusion chromatography (SEC), which sorts molecules according to size, gives the ability to analyze polydisperse samples, as well as to obtain information on branching and molecular conformation. This means that both the number-average and mass-average values for molar mass and size may be obtained for most samples. Furthermore, one has the ability to calculate the distributions of the molar masses and sizes.4.3 Multi-angle laser light scattering (MALS) is a technique where measurements are made simultaneously over a range of different angles and used to determine the scattering at 0°, which directly relates to molecular weight. MALS detection can be used to obtain information on molecular size, since this parameter is determined by the angular variation of the scattered light. This can be related to branching, aggregation, and molecular conformation. Molar mass can also be determined by detecting scattered light at a single low angle (LALS) and assuming that this is not significantly different from the scattering at 0°.4.4 Size exclusion chromatography uses columns, which are typically packed with polymer particles containing a network of uniform pores into which solute and solvent molecules can diffuse. While in the pores, molecules are effectively trapped and removed from the flow of the mobile phase. The average residence time in the pores depends upon the size of the solute molecules. Molecules that are larger than the average pore size of the packing are excluded and experience virtually no retention; these are eluted first, in the void volume of the column. Molecules which penetrate the pores will have a larger volume available for diffusion; their retention will depend on their molecular size, with the smaller molecules eluting last.4.5 For polyelectrolytes, dialysis against the elution buffer has been suggested, in order to eliminate Donnan-type artifacts in the molar mass determination by light scattering (1, 2).6 However, in the present method, the size exclusion chromatography step preceding the light scatter detection is an efficient substitute for a dialysis step. The sample is separated on SEC columns with large excess of elution buffer for 30 to 40 min, and it is therefore in full equilibrium with the elution buffer when it reaches the MALS detector.1.1 This test method covers the determination of the molar mass (typically expressed as grams/mole) of sodium alginate intended for use in biomedical and pharmaceutical applications as well as in tissue-engineered medical products (TEMPs) by size exclusion chromatography with multi-angle laser light scattering detection (SEC-MALS). A guide for the characterization of alginate has been published as Guide F2064.1.2 Alginate used in TEMPs should be well characterized, including the molar mass and polydispersity (molar mass distribution) in order to ensure uniformity and correct functionality in the final product. 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.

定价： 590元 / 折扣价： 502 元 加购物车

5.1 Rock for erosion control consists of individual pieces of natural stone. The ability of these individual pieces of stone to resist deterioration due to weathering action affects the stability of the integral placement of rock for erosion control and hence, the stability of construction projects, structures, shorelines, and stream banks.5.2 The sodium sulfate or magnesium sulfate soundness test is one method by which to estimate qualitatively the durability of rock under weathering conditions. This test method was developed to be used in conjunction with additional test methods listed in Practice D4992. This test method does not provide an absolute value, but rather an indication of the resistance to freezing and thawing; therefore, the results of this test method are not to be used as the sole basis for the determination of rock durability.5.3 This test method has been used to evaluate many different types of rocks. There have been occasions when test results have provided data that have not agreed with the durability of rock under actual field conditions; samples yielding a low soundness loss have disintegrated in actual usage, and the reverse has been true.NOTE 1: The quality of results produced by this standard is dependent on the competence of the personnel performing it and suitability of the equipment and facilities used. Agencies that meet the criteria of Practice D3740 are generally considered capable of competent and objective testing/sampling/inspection/etc. Users of this standard are cautioned that compliance with Practice D3740 does not in itself assure reliable results. Reliable results depend on many factors and Practice D3740 provides a means of evaluating some of them.1.1 This test method covers test procedures for evaluating the soundness of rock for erosion control by the effects of a sodium or magnesium sulfate solution on slabs of rock. It is an accelerated weathering test. The rock slabs, prepared in accordance with procedures in Practice D5121, are intended to be representative of erosion control sized materials and their inherent weaknesses. The test is appropriate for breakwater stone, armor stone, riprap and gabion sized rock materials.1.1.1 The limitations of this test are twofold. First the test is a simulation of freezing and thawing conditions using accelerated life cycling techniques. The test evaluates the internal expansive force derived from the rehydration of the salt upon re-immersion, an event that may not occur in some natural environments, to simulate the expansion of water rather than the actual freezing of water. Secondly, the size of the cut rock slab specimens may eliminate some of the internal defects present in the rock structure. The test specimens may not be representative of the quality of the larger rock samples used in construction. Careful examination of the rock source and proper sampling are essential in minimizing this limitation.1.2 The use of reclaimed concrete and other materials for erosion control is beyond the scope of this test method.1.3 Units—The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in nonconformance with the standard. Reporting of test results in units other than SI shall not be regarded as nonconformance with this standard.1.3.1 The gravitational system of inch-pound units is used when dealing with inch-pound units. In this system, the pound (lbf) represents a unit of force (weight), while the unit for mass is slugs. The slug unit is not given unless dynamic (F=ma) calculations are involved.1.3.2 It is common practice in the engineering/construction profession to concurrently use pounds to represent both a unit of mass (lbm) and of force (lbf). This practice implicitly combines two separate systems of units; the absolute and the gravitational systems. It is scientifically undesirable to combine the use of two separate sets of inch-pound units within a single standard. As stated, this standard includes the gravitational system of inch-pound units and does not use/present the slug unit for mass. However, the use of balances or scales recording pounds of mass (lbm) or recording density in lbm/ft3 shall not be regarded as nonconformance with this standard.1.3.3 Calculations are done using only one set of units; either SI or gravitational inch-pound. Other units are permissible, provided appropriate conversion factors are used to maintain consistency of units throughout the calculations, and similar significant digits or resolution, or both are maintained.1.4 All observed and calculated values shall conform to the guidelines for significant digits and rounding established in Practice D6026, unless superseded by this standard.1.4.1 For purposes of comparing measured or calculated value(s) with specified limits, the measured or calculated value(s) shall be rounded to the nearest decimal or significant digits in the specified limits.1.4.2 The procedures used to specify how data are collected/recorded or calculated, in this standard are regarded as the industry standard. In addition, they are representative of the significant digits that generally should be retained. The procedures used do not consider material variation, purpose for obtaining the data, special purpose studies, or any considerations for the user’s objectives; and it is common practice to increase or reduce significant digits of reported data to be commensurate with these considerations. It is beyond the scope of this standard to consider significant digits used in analytical methods for engineering design.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 The sodium bicarbonate coated tube filter method provides a means of separating and collecting atmospheric gaseous fluoride and particulate fluoride samples.5.2 Since the samples are collected on the dry tube and filter, the fluoride may be eluted with a small volume of eluant (see Section 10 for specific instructions on fluoride elution). Elution into a small volume and the sensitivity of the analytical methods employed allow the analysis of the collected fluoride to fractional parts of a microgram per cubic metre on samples taken for a 12-h period.1.1 The sodium bicarbonate-coated glass tube and membrane filter method provides a means for the separation and collection of gaseous atmospheric forms of fluoride reactive with sodium bicarbonate and particulate forms of fluoride which are collected by a filter. The test method is applicable to 12-h sampling periods, collecting 1 to 500 μg of gaseous fluoride at a 15 L/min (0.5 ft3/min) sampling rate or about 0.1 to 50 μg/m3. The length of the sampling period can therefore be adjusted so that the amount of fluoride collected will fall within this range. The actual lower limit of the test method will depend upon the sensitivity of the analytical method employed and the quality of reagents used in tube preparation and analysis. It is recommended that the lower limit of detection should be considered as two times the standard deviation of the monthly arithmetic mean blank value. Any values greater than the blank by less than this amount should be reported as “blank value.”1.2 The values stated in SI units are to be regarded as standard. The values given in parentheses are mathematical conversions to inch-pound units that 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.

定价： 590元 / 折扣价： 502 元 加购物车

5.1 Excessive amounts of sodium can indicate the presence of materials that cause high wear of burner pumps and valves, and contribute to deposits of boiler heating surfaces.1.1 This test method covers the determination of sodium in residual fuel oil by means of a flame photometer. Its precision in low ranges limits its application to samples containing more than 15 mg/kg sodium. Other elements commonly found in residual fuel oil do not interfere.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 problems 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 hazard statements see 7.3, 7.5, 7.7, 9.2, 7.8, 7.9, and Note 3.1.4 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.

定价： 515元 / 折扣价： 438 元 加购物车

定价： 515元 / 折扣价： 438 元 加购物车

4.1 This test method is based on the cold oxidation of the glycerol by sodium metaperiodate in a strong acidic medium. Formaldehyde and formic acid are produced in this reaction and the latter is used to measure the glycerol content by titration with standard sodium hydroxide solution, to a pH 8.1 ± 0.1. The glycerol content is expressed as a percentage (m/m).4.2 Interferences—The glycerin sample should be free of organic compounds with more than two hydroxyl groups on adjacent carbon atoms (for example, sugars, glycols). These types of compounds may produce formic acid which interferes with the determination of the glycerol content.1.1 This test method provides the quantitative determination of glycerin by the titrimetric method. It is applicable to all glycerin or glycerin/water mixtures >75 %.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 may involve hazardous materials, operations, and equipment. This standard does not purport to address all of the safety concerns associated with its use. It is the responsibility of the user of this standard to consult the established and appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. Specific precautions are listed in Section 8.1.4 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.

定价： 515元 / 折扣价： 438 元 加购物车

定价： 590元 / 折扣价： 502 元 加购物车

4.1 This practice is normally used for stress-corrosion screening for the development of Al-Zn-Mg-Cu alloys containing less than 0.26 % copper. Effects on stress-corrosion resistance due to variables such as composition, thermo-mechanical processing, other fabrication variables, and magnitude of applied stress may be compared.4.2 For a given mechanical method of stressing, the relative stress-corrosion resistance of the low copper Al-Zn-Mg-Cu alloys in atmospheric exposure correlates better with performance in boiling 6 % sodium chloride solution than with other accelerated testing media (7-9). In addition, this practice is relatively rapid.4.3 This practice is not applicable to 2XXX (Al-Cu), 5XXX (Al-Mg), 6XXX (Al-Mg-Si), and the 7XXX (Al-Zn-Mg-Cu) series alloys containing more than 1.2 % copper.4.3.1 For 7XXX series alloys containing between 0.26 % and 1.2 % copper, there is no general agreement as to whether this practice or Practice G44 correlates better with stress-corrosion resistance in service (5-8, 10).1.1 This practice primarily covers the test medium which may be used with a variety of test specimens and methods of applying stress. Exposure times, criteria of failure, and so on, are variable and not specified.1.2 This stress-corrosion testing practice is intended for statically loaded smooth non-welded or welded specimens of 7XXX series Al-Zn-Mg-Cu alloys containing less than 0.26 % copper.1.3 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered 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. See Section 8 for additional precautions.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.

定价： 515元 / 折扣价： 438 元 加购物车

4.1 Anion impurities in caustic soda and caustic potash are monitored by manufacturers and users for quality control of the products. Anions of primary interest are chloride, chlorate, and sulfate. This test method has determined precision estimates only for these three impurities.1.1 This test method covers the determination of anionic impurities in 50 % caustic soda (sodium hydroxide) and 50 % caustic potash (potassium hydroxide) solutions using ion chromatography (IC). Anions that can be determined at concentrations of approximately 0.1 to 1000 ug/g (ppm) include: bromide, chlorate, chloride, fluoride, nitrate, phosphate, and sulfate.1.2 By varying the sample size, this test method can be used for anhydrous caustic soda and caustic potash products, as well as other concentrations of liquid products.1.3 This test method is not intended to be used to quantify chloride in caustic soda where the sodium chloride concentration is approximately 1 %. For the most accurate determinations, it is recommended that high concentrations of chloride be analyzed using a potentiometric titration procedure, such as the one described in Test Methods E291.1.4 The values stated in SI units are to be regarded as standard. The values given in parentheses are for information only.1.5 Review the current appropriate Safety Data Sheets (SDS) for detailed information concerning toxicity, first aid procedures, and safety precautions.1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Specific hazards statements are given in Section 8.

定价： 590元 / 折扣价： 502 元 加购物车

3.1 Caustic soda and caustic potash are used in a large number of manufacturing processes. The chemicals are available in several grades depending on their intended use. The test methods listed in 1.2 provide procedures for analyzing caustic soda and caustic potash to determine if they are suitable for their intended use.1.1 These test methods cover only the analyses usually required on the following commercial products:1.1.1 Caustic soda (sodium hydroxide), 50 and 73 % liquors; anhydrous (solid, flake, ground, or powdered), and1.1.2 Caustic potash (potassium hydroxide), 45 % liquor; anhydrous (solid, flake, ground, or powdered).1.2 The analytical procedures appear in the following order:Alkalinity (Total), Titrimetric (for 50 to 100 % NaOH and 45 to 100 % KOH) 3 to 4Carbonate, Gas-Volumetric (0.001 g CO2, min) 4 to 7Carbonate, Gravimetric (0.001 g CO2, min) 7 to 10Chloride, Titrimetric, (0.001 g Cl−, min) 10 to 11Chloride, Potentiometric Titration (0.3 to 1.2 %) 11 to 12Chloride, Ion Selective Electrode (0.6 to 120 μg/g) 12 to 13Iron, Photometric (0.005 mg Fe, min) 13 to 15Sulfate, Gravimetric, (0.002 g SO3, min) 15 to 16Keywords 161.3 Units—The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard with the exception of inch-pound units for apparatus descriptions.1.4 In determining the conformance of the test results using this method to applicable specifications, results shall be rounded off in accordance with the rounding-off method of Practice E29.1.5 Review the current Safety Data Sheet (SDS) for detailed information concerning toxicity, first-aid procedures, handling, and safety precautions.1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. Specific hazard statements are given in Section 6.1.7 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.

定价： 646元 / 折扣价： 550 元 加购物车

4.1 This practice is especially useful for evaluating the adequacy of quenching when performed on material in the as-quenched condition. The practice may also be used to study the effect of subsequent thermal processes (for example, paint or bonding cures) or of actual precipitation treatments on the inherent type of corrosion. Intergranular corrosion resistance of heat treatable aluminum alloys is often directly related to the quenching conditions applied after solution heat treatment and to the subsequent aging treatment.44.2 This practice is not well suited for non-heat treatable work hardening aluminum alloys, such as the 1XXX, 3XXX, and 5XXX series (see Test Method G67).4.3 This practice does not deal with the interpretation of resulting intergranular corrosion. The significance of the extent and depth of any intergranular corrosion resulting from this test is to be agreed upon between producer and user.1.1 This practice covers the procedures for immersion tests in sodium chloride + hydrogen peroxide solution. It is primarily for tests of wrought heat treatable aluminum alloys (2XXX and 7XXX) but may be used for other aluminum alloys, including castings. It sets forth the specimen preparation procedures and the environmental conditions of the test and the means for controlling them.1.2 This practice is intended for evaluations during alloy development and for evaluating production where it may serve as a control test on the quality of successive lots of the same material (see MIL-H-6088 and U.S. Federal Test Method Std. 151b). Therefore strict test conditions are stipulated for maximum assurance that variations in results are attributable to lot-to-lot differences in the material being tested.NOTE 1: This practice does not address sampling or interpretation or significance of results.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.

定价： 515元 / 折扣价： 438 元 加购物车

This test method covers commercial synthetic detergents and built detergent formulations that do not contain organic additives such as amides. This test method involves measurement of the ultraviolet absorbance of the sample at the maximum absorbance point for sodium alkylbenzene sulfonate and at a selected background point in order to determine the amount of active ingredient present. The percentage of alcohol-soluble matter, absorptivity value and percentage of active ingredient shall be calculated in accordance to the specified requirements.1.1 This test method covers commercial synthetic detergents and built detergent formulations that do not contain organic additives such as amides. Optical dyes and materials normally found in formulated detergents do not interfere; however, materials other than sulfonates that possess strong ultraviolet absorptions must be absent. The indicated sample size and aliquoting scheme is based on samples containing 30 to 40% of active ingredient.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 and health practices and determine the applicability of regulatory limitations prior to use. Material Safety Data Sheets are available for reagents and materials. Review them for hazards prior to usage.

定价： 515元 / 折扣价： 438 元 加购物车

5.1 Palladium and gold coatings are often specified for the contacts of separable electrical connectors and other devices. Electrodeposits are the form of gold that is most used on contacts, although it is also employed as inlay or clad metal and as weldments on the contact surface. The intrinsic nobility of gold and palladium alloys enables it to resist the formation of insulating oxide films that could interfere with reliable contact operation.5.2 In order for these coatings to function as intended, porosity, cracks, and other defects in the coating that expose base-metal substrates and underplates must be minimal or absent, except in those cases where it is feasible to use the contacts in structures that shield the surface from the environment or where corrosion inhibiting surface treatments for the deposit are employed. The level of porosity in the coating that may be tolerable depends on the severity of the environment to the underplate or substrate, design factors for the contact device like the force with which it is mated, circuit parameters, and the reliability of contact operation that it is necessary to maintain. Also, when present, the location of pores on the surface is important. If the pores are few in number and are outside of the zone of contact of the mating surfaces, their presence can often be tolerated.5.3 Methods for determining pores on a contact surface are most suitable if they enable their precise location and numbers to be determined. Contact surfaces are often curved or irregular in shape, and testing methods should be suitable for them. In addition, the severity of porosity-determining tests may vary from procedures capable of detecting all porosity to procedures that detect only highly porous conditions.5.4 The present test practice is capable of detecting virtually all porosity or other defects that could participate in corrosion reactions with the substrate or underplate. In addition, it can be used on contacts having complex geometry such as pin-socket contacts (although with deep recesses it is preferred that the contact structures be opened to permit reaction of the vapors with the interior significant surfaces).5.5 The relationship of porosity levels revealed by particular tests to contact behavior must be made by the user of these tests through practical experience or by other forms of testing. Thus, absence of porosity in the coating may be a requirement for some applications, while a few pores in the contact zone may be acceptable for others. The acceptable number, sizes and locations of the pore corrosion products shall be as specified on the appropriate drawing or specification.5.6 This test is considered destructive in that it reveals the presence of porosity by contaminating the surface with corrosion products and by undercutting the coating at pore sites or at the boundaries of the unplated areas. Any parts exposed to this test shall not be placed in service.5.7 The test is simple and inexpensive. The cost associated with the test is very low, using standard basic equipment found in an industrial laboratory. There are minimal waste disposal issues associated with the procedure. The test is very popular because of its very quick means of assessing the likelihood of plating quality problems, prior to the performance of accelerated environmental testing on the 1 to 2 week scale at much greater expense.1.1 This test practice covers equipment and methods for revealing the porosity of gold and palladium coatings, particularly electrodeposits and clad metals used on electrical contacts.1.2 This test practice is suitable for coatings containing gold or 75 % by mass of palladium on substrates of copper, nickel, and their alloys, which are commonly used in electrical contacts.1.3 A variety of full porosity testing methods is described in the literature.2,3 These porosity Test Methods are B735, B741, B798, B799, and B809. An ASTM Guide to the selection of porosity tests for electrodeposits and related metallic coatings is available as Guide B765.1.4 The values stated in SI units are to be regarded as standard. The values given in parentheses are for information only.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. For specific hazards, see Section 6.1.6 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.

定价： 515元 / 折扣价： 438 元 加购物车

定价： 515元 / 折扣价： 438 元 加购物车

5.1 Sodium salts are very soluble, and sodium leached from soil and rocks tends to remain in solution. Water with a high ratio of sodium to calcium is deleterious to soil structure.5.2 Sodium is not particularly significant in potable water except for those persons having an abnormal sodium metabolism, but water supplies in some areas contain sufficient sodium to be a factor in the planning of sodium-free diets.5.3 The use of sodium salts is common in industry; therefore, many industrial wastewaters contain significant quantities of sodium. For high-pressure boiler feed-water even trace amounts of sodium are of concern.1.1 This test method covers the determination of low amounts of sodium in waters2 having low solids content. The applicable range of this test method is from 0.20 to 3.0 mg/L when using the 589.6-nm resonance line. This range may be extended upward by dilution of an appropriate aliquot of sample or by use of the less-sensitive 330.2-nm resonance line (see Test Method D3561). Many workers have found that this test method is reliable for sodium levels to 0.005 mg/L, but use of this test method at this low level is dependent on the configuration of the aspirator and nebulizer system available in the atomic absorption spectrophotometer as well as the experience and skill of the analyst. The precision and bias data presented are insufficient to justify use of this test method in the 0.005 to 0.20-mg/L range.1.2 This test method has been used successfully with spiked reagent water. It is the analyst's responsibility to assure the validity of the test method to other low dissolved solids matrices.1.3 The values stated in SI units are to be regarded as standard. The values given in parentheses are mathematical conversions to inch-pound units that are provided for information only and are not considered 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.

定价： 515元 / 折扣价： 438 元 加购物车