【国外标准】 Standard Test Method for Sulfur Content of Cellulosic Materials by X-Ray Fluorescence

4.1 This procedure provides a method for determining sulfur content in cellulosic materials by nondestructive means. Sulfur may be in the form of sulfate esters that may contribute to thermal instability. Sulfur can also be present as salts that can cause haze in solutions.1.1 This test method covers determination of sulfur content of cellulosic materials by X-ray fluorescence.1.2 Using appropriate standards, the range of the procedure is from approximately 10 ppm to 20 % sulfur.1.3 This test method is proposed specifically as an alternative to Test Methods D871, sections on , Apparatus, Reagents, Procedure and Calculation of Hydroxyl Content, and Test Methods D817, sections on Summary of Test Method, , Apparatus, Reagents, and Procedure of Hydroxyl Content. As applied to cellulose esters it measures the combined sulfur and sulfur in the accompanying inorganic salts.1.4 To determine combined sulfur, the sample, when soluble, must first be reprecipitated into dilute acid to remove the noncombined sulfur compounds.1.5 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.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. For a specific hazard statement, see 7.2.1.1.7 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.