定价： 2081元 / 折扣价： 1853 元 加购物车

定价： 2081元 / 折扣价： 1853 元 加购物车

定价： 2081元 / 折扣价： 1853 元 加购物车

定价： 2081元 / 折扣价： 1853 元 加购物车

定价： 1290元 / 折扣价： 1149 元 加购物车

定价： 2081元 / 折扣价： 1853 元 加购物车

定价： 2081元 / 折扣价： 1853 元 加购物车

本部分规定了炭阳极用煅后石油焦Lc(微晶尺寸)值的测定方法。
本部分适用于炭阳极用煅后石油焦Lc(微晶尺寸)值的测定。

定价： 14元 / 折扣价： 12 元 加购物车

5.1 Separation and identification of stabilizers used in the manufacture of polyethylene resins are necessary in order to correlate performance properties with polymer composition. This test method provides a means to determine the polymer additives listed in Table 1 in polyethylene samples. This test method is capable of the determination of other antioxidants, but the stability of these during extraction has not been investigated.5.2 The additive extraction procedure is made effective by the relatively low solubility of the polymer sample in solvents generally used for liquid chromatographic analysis. In this method, isopropanol and cyclohexane were chosen because of their excellent extraction efficiencies as well as for safety reasons. Other solvents including ethylacetate, isobutanol, chloroform and methylene chloride can also be used.5.3 Methods other than refluxing that have been used to remove additives from the polymer matrix including pressurized liquid, microwave, ultrasonic, and supercritical fluid extractions. For the separation of the extracted additives, SFC and GC have been used successfully for several of the additives.5.4 Under optimum conditions, the lowest level of detection for an antioxidant is approximately 2 ppm.1.1 This test method covers a liquid-chromatographic procedure for the separation of primary and secondary antioxidant and slip additives currently used in polyethylene plastics. These additives are extracted with either isopropanol (resin densities < 0.94 g/cm3) or cyclohexane (resin densities > 0.94 g/cm3) prior to liquid-chromatographic separation. The ultraviolet absorbance of the eluting compound(s) is measured and quantitation is performed using external calibration.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. Specific precautionary statements are given in Section 9.NOTE 1: There is no known ISO equivalent to this standard.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 加购物车

定价： 590元 加购物车

定价： 515元 加购物车

5.1 The crystallinity of petroleum coke, as reflected by the Lc value, is a general measure of quality affecting suitability for end use and is a function of the heat treatment.5.2 The crystallite thickness is used to determine the extent of such heat treatment, for example, during calcination. The value of the Lc determined is not affected by coke microporosity or the presence of foreign, non-crystalline materials such as dedust oil.1.1 This test method covers the determination of the mean crystallite thickness of a representative, pulverized sample of calcined petroleum coke by interpretation of a X-ray diffraction pattern produced through conventional X-ray scanning techniques.1.2 Calcined petroleum coke contains crystallites of different thicknesses. This test method covers the determination of the average thickness of all crystallites in the sample by empirical interpretation of the X-ray diffraction pattern. The crystallite diameter (La) is not determined by this test method.1.3 The values stated in SI (metric) units are to be regarded as the standard. The inch-pound units given in parentheses are provided for information purposes only.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 加购物车

5.1 Nitrosamines are a class of nitrogen-containing compounds with a known occurrence in wastewater. They may also be created in deionization and are a potential contaminant in water for reuse. The World Health Organization has issued a guideline for NDMA in drinking water at 0.1 µg/L. NDMA may occur in chlorinated effluents and other wastewaters. Other methods for nitrosamines employ solid phase extraction, which may not be applicable to wastewaters that contain particulate matter or a high organic load. This method analyses nitrosamines directly using LC-MS/MS.1.1 This test method covers the liquid chromatography tandem mass spectrometry (LC-MS/MS) detection and quantitation of N-nitrosamines after direct injection. It has been validated for groundwater, surface water, wastewater influents, and wastewater effluents. This test method is not limited to these aqueous matrices; however, the applicability of this test method to other aqueous matrices must be demonstrated.1.2 This test method is applicable to nitrosamines that can be chromatographed and detected using a mass spectrometry procedure. Table 1 lists the compounds that have been validated for this test method. This test method is not limited to the compounds listed in Table 1; however, the applicability of the test method to other compounds must be demonstrated.1.3 Analyte concentrations from 0.05 µg/L up to approximately 5 µg/L may be determined without dilution of the sample. Analytes with insufficient sensitivity will not be detected, but they can be measured with acceptable accuracy and precision when present in sufficient amounts. In addition, newer instruments, or instruments of improved sensitivity may be used to lower detection limits.1.4 Analytes that are not separated chromatographically, but that have different mass spectra and noninterfering quantitation ions, can be identified and measured in the same calibration mixture or water sample. Analytes that have very similar product ions cannot be individually identified and measured in the same calibration mixture or water sample unless they have different retention times.1.5 It is the responsibility of the user to ensure the validity of this test method for untested matrices.1.6 This test method is restricted to use by or under the supervision of analysts experienced in the use of a liquid chromatograph with tandem mass spectrometry (LC-MS/MS).1.7 Depending on data usage, you may modify this test method but limit to modifications that improve performance while still meeting method quality acceptance criteria. Shortening the chromatographic run simply to save time is not allowed. Use Practice E2935 or similar statistical tests to confirm that modifications produce equivalent results on non-interfering samples. In addition, use Guide E2857 or equivalent statistics to re-validate the modified test.1.8 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.9 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.1.10 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 加购物车

5.1 This test method has been developed by the U.S. EPA Region 5 Chicago Regional Laboratory (CRL). 5.2 PFAS are widely used in various industrial and commercial products; they are persistent, bio-accumulative, and ubiquitous in the environment. PFAS have been reported to exhibit developmental toxicity, hepatotoxicity, immunotoxicity, and hormone disturbance. A draft Toxicological Profile for Perfluoroalkyls from the U.S. Department of Health and Human Services is available.7 PFAS have been detected in soils, sludges, and surface and drinking waters. Hence, there is a need for a quick, easy, and robust method to determine these compounds at trace levels in various soil matrices for understanding of the sources and pathways of exposure. 5.3 This method has been used to determine selected PFAS in sand (Table 4) and four ASTM reference soils (Table 5). 1.1 This procedure covers the determination of selected polyfluorinated alkyl substances (PFAS) in a soil matrix using solvent extraction, filtration, followed by liquid chromatography (LC) and detection with tandem mass spectrometry (MS/MS). These analytes are qualitatively and quantitatively determined by this method. This method adheres to multiple reaction monitoring (MRM) mass spectrometry. This procedure utilizes a quick extraction and is not intended to generate an exhaustive accounting of the content of PFAS in difficult soil matrices. An exhaustive extraction procedure for PFAS, such as published by Washington et al.,2 for difficult matrices should be considered when analyzing PFAS. The approach from this standard was utilized to screen laboratory coats (textiles) to identify if PFAS would be leached from the materials. 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 The method of detection limit3 and reporting range4 for the target analytes are listed in Table 1. 1.3.1 The reporting limit in this test method is the minimum value below which data are documented as non-detects. Analyte detections between the method detection limit and the reporting limit are estimated concentrations and are not reported following this test method. In most cases, the reporting limit is calculated from the concentration of the Level 1 calibration standard as shown in Table 2 for the PFAS after taking into account a 2 g sample weight and a final extract volume of 10 mL, 50 % water/50 % MeOH with 0.1 % acetic acid. The final extract volume is assumed to be 10 mL because 10 mL of 50 % water/50 % MeOH with 0.1 % acetic acid was added to each soil sample and only the liquid layer after extraction is filtered, leaving the solid and any residual solvent behind. It is raised above the Level 1 calibration concentration for PFOS, PFHxA, FHEA, and FOEA; these compounds can be identified at the Level 1 concentration but the standard deviation among replicates at this lower spike level resulted in a higher reporting limit. 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： 843元 加购物车

定价： 843元 加购物车