ASTM D3635-13(R2021) pdf free download

ASTM D3635-13(R2021) pdf free download.Standard Test Method for Dissolved Copper In Electrical Insulating Oil By Atomic Absorption Spectrophotometry
1. Scope
1.1 This test method covers the determination of copper in new or used electrical insulating oil of petroleum origin by atomic absorption spectrophotometry. 1.2 The lowest limit of detectability is primarily dependent upon the method of atomization, but also upon the energy source, the fuel and oxidant, and the degree of electrical expansion of the output signal. The lowest detectable concen- tration is usually considered to be equal to twice the maximum variation of the background. For flame atomization, the lower limit of detectability is generally in the order of 0.1 ppm or 0.1 mg/kg. For non-flame atomization, the lower limit of detect- ability is less than 0.01 ppm. 1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.4 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 appro- priate safety, health, and environmental practices and deter- mine the applicability ofregulatory limitations prior to use. 1.5 This international standard was developed in accor- dance with internationally recognized principles on standard- ization established in the Decision on Principles for the Development of International Standards, Guides and Recom- mendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
3. Summary of Test Method
3.1 The test specimen of oil is filtered and diluted with an appropriate organic solvent and analyzed in an atomic absorp- tion spectrophotometer. Alternate procedures are provided for instruments employing flame and non-flame atomization. Con- centration is determined by means of calibration curves pre- pared from standard samples.
4. Significance and Use
4.1 Electrical insulating oil may contain small amounts of dissolved metals derived either directly from the base oil or from contact with metals during refining or service. When copper is present, it acts as a catalyst in promoting oxidation of the oil. This test method is useful for research for new oils and to assess the condition of service-aged oils. Consideration should be given to the limits of detection outlined in the scope.
8. Procedure A—Flame Atomization
8.1 Preparation of Standard Copper Solution (500 ppm Cu): 8.1.1 Dissolve 0.3030 g of NIST Standard No. 1080, bis (1-phenyl-1, 3-butanediono) copper (II), according to instruc- tions received with the standard, and dilute to 100.0 g 6 0.1 g with new oil to make a 500 ppm standard copper solution. Shake well. 8.2 Preparation ofWorking Standards: 8.2.1 Dilute 2.00 g of the standard copper solution to 100 mL with new oil to give an intermediate standard containing approximately 10µ g/mL Cu. This working standard contains the 10 µg/mL Cu added plus any copper present in the new oil used to make the standard. If the copper content of the new oil is not known, it must be determined. When detectable levels of copper are suspected in the new oil or the copper content is simply unknown, refer to 8.4.1.5. 8.2.2 Add to new oil aliquots of 10 µg/mL Cu solution so as to obtain four standards containing additions of 0.0 µg ⁄mL, 0.5 µg ⁄mL, 1.0 µg ⁄mL, and 3.0 µg/mL Cu; dilute each with MIBK to obtain an oil to ketone ratio of10 % (V/V) as follows (Note 2): Working Standard 10 µg/mL Cu standard, mL New Oil, mL MIBK, mL No. 1 (blank) 0.0 10.0 90 No. 2 0.5 9.5 90 No. 3 1.0 9.0 90 No. 4 3.0 7.0 90 N OTE 2—The new oil used to make these dilutions must be the same new oil used to make the 10 µg/mL standard. Good transfers can be effected if a 50-mL buret is used for the new oil and a 5-mL buret is used for the 10µ g/mL Cu standard. Do not transfer the solutions too rapidly. 4 8.2.3 Shake well after dilution with MIBK. 8.3 Preparation ofTest Specimen: 8.3.1 Filter the test specimen using a 0.45 µm filter. 8.3.2 Using a 10-mL glass syringe, transfer 10 mL of the filtered test specimen to a 100-mL volumetric flask. Dilute to volume with MIBK and shake well (Note 3).8.4.1.2 For narrow slit burners, reduce flow as low as possible while maintaining the flame on the burner head. For three slit burners, reduce fuel flow as low as possible while aspirating neat MIBK so that orange streaks rising from the rivet heads are still visible in the flame. 8.4.1.3 Adjust the aspiration rate for maximum absorbance while burning No. 4 working standard. 8.4.1.4 Set the instrument at zero absorbance while burning No. 1 working standard. 8.4.1.5 Set the instrument at zero absorbance while burning methyl isobutyl ketone (MIBK). Plot a standard curve of absorbance versus copper concentration for standards Nos. 1–4. Extrapolate this curve to zero absorbance. The absolute value of the copper concentration at zero absorbance (a negative number) provides an estimate of the copper contained in the standard oil. 8.4.2 Run the standards and test specimen in the following order: standards, test specimen, standards, test specimen, and standards.