Abstract
A sample of 100 to 200mg was treated with nitric acid and hydrogen peroxide, ignited, and followed by HF-treatment to remove dissoluble and organic matters. After adding silicon internal standard, the undissolved part was collected on a membrane filter, which was subjected to X-ray diffraction analysis. Rutile or corundum of 0.1 to 1.0mg can be determined from the integral intensity ratio against silicon. Some pairs of diffraction lines suitable for determination, influences of coexisting substances, and the processes of chemical treatment are discussed. Furthermore, the present method has been applied successfully to several atmospheric dust samples collected in urban, industrial, and farming areas. Rutile and corundum in the samples were concentrated more than 10 times. The detection limits of rutile and corundum were 0.04% and 0.02%, respectively.
