ASTM D5184 Standard Test Methods for Determination of Aluminum and Silicon in Fuel Oils by Ashing, Fusion, Inductively Coupled Plasma Atomic Emission Spectrometry, and Atomic Absorption Spectrometry
6. Apparatus
6.1 Balance, capable of weighing to 0.1 g, capacity of 150 g.

6.2 Choice of Instrument:
6.2.1 Inductively-Coupled Plasma Atomic Emission
Spectrometer - Either a sequential or simultaneous spectrometer is suitable, ifequipped with an ICP torch and RF generator to form and sustain the plasma.

6.2.2 Atomic Absorption Spectrometer - A suitable instrument will consist of modulated hollow cathode lamps or other sources of resonance radiation of aluminum and silicon, a nitrous oxide/acetylene burner, and a spectrometer with a suitable detection and read-out system.

6.3 Homogenizer, non-aerating, high-speed shear mixer to homogenize the sample.

NOTE 1 - Ultrasonic bath and ultrasonic probe type homogenizers were not evaluated in the development of these test methods.

6.4 Electric Muffle Furnace, capable of being maintained at temperatures of 550 +/- 25°C and 925 +/- 25°C. The furnace preferably having suitable apertures at front and rear to allow a slow, natural draft of air to pass through.

6.5 Electric Hot Plate, with or without magnetic stirring capability.

6.6 Electric Oven, maintained at a temperature of 50 to 60°C.

6.7 Graduated Cylinders, 10, 25, 50, and 100 mL.

6.8 Pipettes, 1, 2, 5, 10, 20, and 25 mL.

6.9 Platinum Dish, 100 mL capacity, cleaned with fused potassium hydrogen sulfate.

6.10 Volumetric Flasks, 100 and 1000 mL.

6.11 All glassware must be carefully cleaned with 1 + 1 hydrochloric acid and rinsed thoroughly with water to minimize contamination. The use of chromic acid cleaning solution is not recommended.

6.12 Zirconium crucible with close fitting zirconium lid, 30 to 50 mL capacity.

7. Reagents
7.1 Purity of Reagents - Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society where such specifications are available. Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination.

7.2 Purity of Water - Unless otherwise indicated, reference to water shall be understood to mean reagent water conforming to Type II of Specification D1193.

7.3 Flux - Mixture of 90 % lithium tetraborate and 10 % lithium fluoride.

NOTE 2 - Lithium fluoride is necessary to prevent heavy metal corrosion of the platinum dish and to lower the fusion temperature.

7.4 Hydrochloric acid (36 % (m/m)) - concentrated hydrochloric acid.

7.5 Potassium Hydrogen Sulfate, fused solid.

7.6 2-Propanol (Isopropyl Alcohol) (Warning - Flammable; can be explosive when evaporated to or near dryness.)

7.7 Aqueous Standard Solutions .
7.7.1 Aluminum Standard Solutions - Obtain a ready made, aqueous standard or prepare a standard from aluminum wire.
7.7.1.1 Aluminum Solution (1000 mg/L) - Aqueous, ready made commercial standard.

7.7.1.2 Aluminum Solution (1000 mg/L) - Cut an arbitrary length of 99.99 % minimum purity aluminum wire (2 mm diameter aluminum wire has been found satisfactory). Measure the length to the nearest 0.1 cm and weigh the aluminum wire to the nearest 0.001 g. Determine the mass/cm for the aluminum wire and cut a length of aluminum wire that is calculated to be slightly greater than 1.000 g. Trim off the excess wire until the mass is 1.000 +/- 0.005 g. Dissolve the aluminum wire in 50 mL of concentrated hydrochloric acid. Heat gently. Cool and transfer the solution to 1000 mL volumetric flask. Dilute to the mark with water.

7.7.2 Silicon Standard Solutions - Obtain a ready made, aqueous standard or prepare a standard from silicon dioxide.
7.7.2.1 Silicon Solution (1000 mg/L) - Aqueous, ready made commercial standard.

7.7.2.2 Silicon Solution (1000 mg/L) - Using a zirconium crucible with a close fitting lid, fuse 2.140 +/- 0.0107 g of silicon dioxide (99.99 % purity) with 8 g of sodium hydroxide until a clear melt is obtained. Cool and dissolve the melt in 100 mL ofa solution of1 part hydrochloric acid by volume and 2 parts water by volume. Transfer this solution to a 1000 mL volumetric flask and dilute to the mark with water. Immediately, transfer the contents of the flask to a plastic bottle.

7.8 Tartaric Acid/Hydrochloric Acid Solution - Dissolve 5 g of tartaric acid in about 500 mL of water acidified with 40 mL of concentrated hydrochloric acid and dilute to 1000 mL with water.

7.9 Toluene/2-Propanol Solution (1 + 1) - Mix one volume of toluene with one volume of 2-propanol.

7.10 Quality Control (QC) Samples, preferably are portions of one or more liquid petroleum materials that are stable and representative of the samples of interest. These QC samples can be used to check the validity of the testing process as described in Section 18.