Scope:

Ceramic glaze is an impervious coating of a vitreous substance that has been fused to a pottery body through firing. The glaze is used to color, decorate or waterproof a ceramic. ASTM C738 covers the standard procedures to determine the amount of lead and cadmium extracted by acetic acid from glazed ceramic surfaces. The extraction process accelerates the release of lead from the glaze. Therefore, it does not represent the actual conditions of usage of such ceramic ware. This test is specific for lead and cadmium.

Test Procedure:

The apparatus needed in this ASTM C738 test includes an atomic absorption spectrometer, lead and cadmium lamps, and glassware of chemical resistant borosilicate glass. Lead, and cadmium are extracted from the test specimen by leaching with 4 % acetic acid for 24 hours at 20 to 24°C (68 to 75°F). And they are measured by flame atomic absorption spectroscopy.

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Specimen size:

Any glazed ceramic article can be tested for the amount of lead and cadmium in its glazed surface.

Data:

In ASTM C738, the volume of acid used is reported. The lead and cadmium leached in parts per million for each unit tested are reported. 

Conclusion:

ASTM C738 covers the standard procedures to determine the amount of lead and cadmium extracted by acetic acid from glazed ceramic surfaces.