ASTM D7212 Standard Test Method for Low Sulfur in Automotive Fuels by Energy-Dispersive X-ray Fluorescence Spectrometry Using a Low-Background Proportional Counter
1. Scope
1.1 This test method specifies an energy-dispersive X-ray fluorescence (EDXRF) method for the determination of the total sulfur content of automotive fuels with a concentration range from 7 mg/kg to 50 mg/kg.
1.1.1 The pooled limit of quantitation of this test method as obtained by statistical analysis of interlaboratory test results is 7 mg/kg sulfur.
1.2 The values stated in SI units are to be regarded as the standard. The preferred concentration units are mg/kg sulfur.
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:
D4045 Test Method for Sulfur in Petroleum Products by Hydrogenolysis and Rateometric Colorimetry
D4057 Practice for Manual Sampling of Petroleum and Petroleum Products
D4177 Practice for Automatic Sampling of Petroleum and Petroleum Products
D6299 Practice for Applying Statistical Quality Assurance and Control Charting Techniques to Evaluate Analytical Measurement System Performance
D6300 Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products and Lubricants
D6792 Practice for Quality System in Petroleum Products and Lubricants Testing Laboratories
D7343 Practice for Optimization, Sample Handling, Calibration, and Validation of X-ray Fluorescence Spectrometry Methods for Elemental Analysis of Petroleum Products and Lubricants
E29 Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications
3. Terminology
3.1 Definitions of Terms Specific to This Standard:
3.1.1 low background proportional counter, n - an X-ray proportional counter that can suppress the noise generated when incident X rays are absorbed near the wall with resulting incomplete charge collection.
3.1.1.1 Discussion - An electrode shield close to the wall detects incomplete charge collection and associated electronic detection circuitry rejects those events. In comparison to conventional proportional counters, this gives lower spectral background and a lower limit of detection.
