定价： 712元 加购物车

定价： 712元 加购物车

定价： 1077元 加购物车

定价： 712元 加购物车

定价： 646元 加购物车

定价： 712元 加购物车

定价： 646元 加购物车

4.1 The presence of 4-CBA and p-TOL in PTA used for the production of polyester is undesirable because they can slow down the polymerization process and 4-CBA imparts coloration to the polymer due to thermal instability.4.2 Determining the amount of 4-CBA and p-TOL remaining from the manufacture of PTA is often required. This test method is suitable for setting specifications and for use as an internal quality control tool where these products are produced or are used.1.1 This test method covers the determination of the 4-Carboxybenzaldehyde (4-CBA) and p-Toluic acid (p-TOL) in purified terephthalic acid (PTA) by reverse phase high performance liquid chromatography (HPLC). This method is applicable for 4-CBA from 2 to 500 mg/kg and for p-TOL from 10 to 500 mg/kg, respectively.1.2 In determining the conformance of the test results using this method to applicable specification, results shall be rounded off in accordance with the rounding-off method of Practice E29.1.3 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： 590元 加购物车

定价： 646元 加购物车

定价： 712元 加购物车

定价： 646元 加购物车

定价： 712元 加购物车

定价： 646元 加购物车

5.1 Nonylphenol,4 octylphenol, and bisphenol A have been shown to have toxic effects in aquatic organisms. The source of nonylphenol and octylphenol is prominently from the use of common commercial surfactants. The most widely used surfactant is NPEO which has an average ethoxylate chain of 9 mol of ethoxylate. The ethoxylate chain is readily biodegraded to form NP1EO and NP2EO, nonylphenol carboxylate (NPEC) and, under anaerobic conditions, nonylphenol. Nonylphenol will also biodegrade, but may be released into environmental waters directly at trace levels. This test method has been investigated for use with surface water and waste treatment effluent samples and is applicable to these matrices. It has not been investigated for use with salt water or solid sample matrices.5.2 The first reported synthesis of BPA was by the reaction of phenol with acetone by Zincke.5 BPA has become an important high volume industrial chemical used in the manufacture of polycarbonate plastics and epoxy resins. Polycarbonate plastic and resins are used in numerous products including electrical and electronic equipment, automobiles, sports and safety equipment, reusable food and drink containers, electrical laminates for printed circuit boards, composites, paints, adhesives, dental sealants, protective coatings, and many other products.6 The environmental source of BPA is predominantly from the decomposition of polycarbonate plastics and resins. BPA is not classified as bio-accumulative by the U.S. Environmental Protection Agency (EPA) and will biodegrade. BPA may be released into the environment waters directly at trace levels through landfill leachate and sewage treatment plant effluents.1.1 This test method covers determination of nonylphenol (NP), nonylphenol ethoxylate (NP1EO), nonylphenol diethoxylate (NP2EO), octylphenol (OP), and bisphenol A (BPA) that are partitioned into organic solvent, separated using gas chromatography and detected with mass selective detection. These compounds or isomer mixtures are qualitatively and quantitatively determined by this test method. This test method adheres to selected ion monitoring mass spectrometry but full scan mass spectrometry has also been shown to work well under these conditions. Either analysis may be used.1.2 The method detection limit (MDL) and reporting limit (RL) for NP, NP1EO, NP2EO, OP, and BPA are listed in Table 1.(A) MDL determined following the Code of Federal Regulations, 40 CFR Part 136, Appendix B.(B) Lowest point of the reporting range is calculated from the LV1 concentration calibration standard in Table 4.1.3 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： 646元 加购物车

定价： 712元 加购物车