ASTM D7111 Standard Test Method for Determination of Trace Elements in Middle Distillate Fuels by Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES)
1. Scope
1.1 This test method covers the determination of selected elements in middle distillate fuels by inductively coupled plasma atomic emission spectrometry (ICP-AES). The specific elements are listed in Table 1. The concentration range of this test method is approximately 0.1 mg/kg to 2.0 mg/kg. The test method may be used for concentrations outside of this range; however, the precision statements may not be applicable. Middle distillate fuels covered in this test method have all distillation fractions contained within the boiling range of 150 °C to 390 °C. This includes, but is not limited to, diesel fuels and aviation turbine fuels.
1.2 This test method is not intended to analyze insoluble particulates. However, very small particulate matter (smaller than a micrometre) will be carried into the plasma and be included in the quantitative analysis.
1.3 This test method may give a result that is higher than the true value if an analyte is present in the sample in a form which is sufficiently volatile. For example, hexamethyldisiloxane will generate a biased high result for silicon.
1.4 The values stated in SI units are to be regarded as 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 and health practices and determine the applicability of regulatory limitations prior to use.
2. Referenced Documents
2.1 ASTM Standards:
D2880 Specification for Gas Turbine Fuel Oils
D3605 Test Method for Trace Metals in Gas Turbine Fuels by Atomic Absorption and Flame Emission Spectroscopy
D4057 Practice for Manual Sampling of Petroleum and Petroleum Products
D4306 Practice for Aviation Fuel Sample Containers for Tests Affected by Trace Contamination
D5185 Test Method for Multielement Determination of Used and Unused Lubricating Oils and Base Oils by Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES)
D6299 Practice for Applying Statistical Quality Assurance and Control Charting Techniques to Evaluate Analytical Measurement System Performance
D6792 Practice for Quality System in Petroleum Products and Lubricants Testing Laboratories
D7260 Practice for Optimization, Calibration, and Validation of Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES) for Elemental Analysis of Petroleum Products and Lubricants
2.2 Military Standard:
MIL-DTL-16884 Fuel, Naval Distillate
3. Terminology
3.1 Definitions:
3.1.1 calibration, n - the determination of the values of the significant parameters by comparison with values indicated by a set of reference standards.
3.1.2 calibration curve, n - the graphical or mathematical representation of a relationship between the assigned (known) values of standards and the measured responses from the measurement system.
3.1.3 calibration standard, n - a standard having an accepted value (reference value) for use in calibrating a measurement instrument or system.
3.1.4 detection limit, n - a stated limiting value that designates the lowest concentration that can be determined with confidence and that is specific to the analytical procedure used.
3.1.5 emission spectroscopy, n - measurement of the energy spectrum emitted by or from an object under some form of energetic stimulation; for example, light or electrical discharge.
3.1.6 inductively coupled plasma, n - a high temperature discharge generated by passing an ionizable gas through a magnetic field induced by a radio frequency coil surrounding the tubes that carry the gas.
3.1.7 radio frequency, n - the range of frequencies between 3 kHz and 300 GHz.
3.1.8 standard, n - a physical or chemical reference used as a basis for comparison or calibration.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 detection limit, n - the lowest concentration value for an element that can be determined by ICP analysis and that is calculated by multiplying three times the standard deviation of ten repetitive element analyses of the blank solution.
3.2.2 internal standard, n - a chemical standard having an accepted value (and added to the fuel test specimen and calibration standard) to determine the emission intensity ratio of an element to the internal standard.
