【国外标准】 Standard Practice for Preparation of Liquid Blends for Use as Analytical Standards

4.1 The laboratory preparation of liquid blends of known composition is required to provide analytical standards for the calibration of chromatographic and other types of analytical instrumentation.1.1 This practice covers a laboratory procedure for the preparation of small volumes of multicomponent liquid blends for use as analytical standards.1.2 This practice is applicable to components that are normally liquids at ambient temperature and pressure, or solids that will form a solution when blended with liquids. Butanes can be included if precaution is used in blending them.1.3 This practice is limited to those components that fulfill the following conditions:1.3.1 They are completely soluble in the final blend.1.3.2 They are not reactive with other blend components or with blend containers.1.3.3 The combined vapor pressure of the blended components is such that there is no selective evaporation of any of the components.1.3.3.1 The butane content of the blend is not to exceed 10 %. (Warning—Extremely flammable liquefied gas under pressure. Vapor reduces oxygen available for breathing.) Components with a vapor pressure higher than butanes are not to be blended.1.4 The values stated in SI units are to be regarded as the 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.