ASTM D3335-85a(R2020) pdf free download

ASTM D3335-85a(R2020) pdf free download.Standard Test Method for Low Concentrations of Lead, Cadmium, and Cobalt in Paint by Atomic Absorption Spectroscopy
1. Scope
1.1 This test method covers the determination of lead 2 contents between 0.01 and 5 %, cadmium contents between 50 and 150 ppm (mg/kg), and cobalt contents between 50 and 2000 ppm (mg/kg) present in the nonvolatile portion of liquid coatings or contained in dried films. There is no reason to believe that higher levels of all three elements could not be determined by this test method, provided that appropriate dilutions and adjustments in specimen size and reagent quan- tities are made. 1.2 Only pigmented coatings were used for evaluating this test method, but there is no reason to believe that varnishes and lacquers could not be analyzed successfully, provided that appropriate precautions are taken. 1.3 This test method is not applicable to the determination of lead in samples containing antimony pigments (low recov- eries are obtained). 1.4 If lead is present in the sample to be analyzed in the form of an organic lead compound at a concentration greater than 0.1 %, small losses oflead may occur, resulting in slightly poorer precision than shown in Section 12. 1.5 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. 1.6 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 of regulatory limitations prior to use. Specific hazard statements are given in Section 7. 1.7 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 specimen of liquid coating or dried film is prepared for analysis by dry ashing. The content of lead, cadmium, or cobalt of an acid extract of the ash is determined by atomic absorption spectroscopy.
4. Significance and Use
4.1 The permissible level of heavy metals in certain coat- ings is specified by governmental regulatory agencies. This test method provides a fully documented procedure for determining low concentrations of lead, cadmium, and cobalt present in both water and solvent-reducible coatings to determine com- pliance.
5. Apparatus
5.1 Atomic Absorption Spectrophotometer, consisting of an atomizer and either a single- or three-slot burner; gas pressure regulating and metering devices for air and acetylene; lead, cadmium, and cobalt source lamps 4 with a regulated constant- current supply; a monochromator and associated optics; a photosensitive detector connected to an electronic amplifier; and a readout device.
N OTE 2—The specimen size called for will give a concentration of approximately 10 to 20 µg/mL lead in the final diluted solution for paints containing approximately 500 ppm (mg/kg) lead, based on the solids. If the material is estimated to contain more or less than 500 ppm lead, the quantity taken should be adjusted accordingly. In the event that signifi- cantly less than 500 ppm lead is expected, a 250-mL high-silica beaker may be used in place ofthe crucible to accommodate specimen weights up to 10 g. The size specified will give a concentration of approximately 2 to 4 µg/mL cadmium in the final diluted solution for paints containing approximately 100 ppm cadmium, based on the solids. The size specified will give a concentration of approximately 10 to 20 µg/mL cobalt in the final diluted solution for paints containing approximately 500 ppm cobalt, based on the solids. N OTE 3—Recover dried paint films from previously coated substrates (being careful not to remove any underlying material from the substrate) or prepare in the laboratory from liquid samples. For the laboratory preparation, flow some of the well-mixed sample onto a clean glass plate. The use ofa paint draw-down bar is recommended to obtain a uniform wet film thickness not exceeding 2 mils (50 µm). Allow the film to dry in an oven at 105°C for a minimum of 1 h. Scrape the dried film off the glass plate, preferably with a single-edge razor blade.