ASTM D7058 Standard Test Method for Determination of the Red Dye Concentration and Estimation of Saybolt Color of Aviation Turbine Fuels and Kerosine Using a Portable Visible Spectrophotometer
1. Scope
1.1 This test method covers the determination of the red dye concentration of aviation turbine fuel and kerosine and the estimation of the Saybolt color of undyed and red dyed (<0.750 mg/L of Solvent Red 26 equivalent) aviation turbine fuel and kerosine. The test method is appropriate for use with aviation turbine fuel and kerosine described in Specifications D1655 and D3699. Red dye concentrations are determined at levels equivalent to 0.026 to 0.750 mg/L of Solvent Red 26 in samples with Saybolt colors ranging from +30 to -16. The Saybolt color of the base fuel for samples dyed red with concentration levels equivalent to 0.026 to 0.750 mg/L of Solvent Red 26 is estimated in the Saybolt Color range +30 to -16. The Saybolt Color for undyed samples is estimated in the Saybolt color range from +30 to -16.
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.
2. Referenced Documents
2.1 ASTM Standards:
D156 Test Method for Saybolt Color of Petroleum Products (Saybolt Chromometer Method)
D1319 Test Method for Hydrocarbon Types in Liquid Petroleum Products by Fluorescent Indicator Adsorption
D1655 Specification for Aviation Turbine Fuels
D3699 Specification for Kerosine
D4052 Test Method for Density, Relative Density, and API Gravity of Liquids by Digital Density Meter
D4057 Practice for Manual Sampling of Petroleum and Petroleum Products
D4177 Practice for Automatic Sampling of Petroleum and Petroleum Products
D6045 Test Method for Color of Petroleum Products by the Automatic Tristimulus Method
E203 Test Method for Water Using Volumetric Karl Fischer Titration
E1655 Practices for Infrared Multivariate Quantitative Analysis
E2056 Practice for Qualifying Spectrometers and Spectrophotometers for Use in Multivariate Analyses, Calibrated Using Surrogate Mixtures
3. Terminology
3.1 Definitions:
3.1.1 Saybolt color, n - an empirical definition of the color of a clear petroleum liquid based on a scale of -16 to +30 and determined by Test Method D156.
3.1.2 surrogate calibration, n - a multivariate calibration that is developed using a calibration set which consists of mixtures with pre-specified and reproducible compositions that contain substantially fewer chemical components than the samples, which will ultimately be analyzed.
3.1.3 surrogate method, n - standard test method that is based on a surrogate calibration.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 product dyes - alkyl derivative of azobenzene-4-azo-2-naphthol (methyl derivatives of Color Index No. 26105) which are more soluble in diesel fuel.
3.2.2 red dye, n - substance that, when added to fuel, absorbs green light and imparts a red color to the product. For this test method, red dye is:
3.2.2.1 Solvent Red 26 - an azobenzene-4-azo-2-naphthol dye of a specific chemical structure that is used to gauge the amount of red dye present in a given sample.
