Platinum (Pt) is the ninth element in Group VIII of the periodic table. It has an atomic number of 78, an atomic weight of 195.1, and valences of 2 and 4. The average abundance of Pt in the earth’s crust is probably <0.01 ppm, and in groundwaters it is <0.1 mg/L. Platinum is usually found in its native state, but also may be found as sperrylite (PtAs2). Platinum is used as a catalyst and in laboratory ware, jewelry, and surgical wire.
The aqueous chemistry in natural waters is relatively unknown, although its solubility is probably controlled by complex compounds. In powder form, platinum can be flammable, and its soluble salts are toxic by inhalation.
Preferably analyze by flame atomic absorption method (Section 3111 B). The inductively coupled plasma mass spectrometric method (Section 3125) also may be applied successfully in most cases (with lower detection levels), even though platinum is not specifically listed as an analyte in the method.