1.1 ,This test method covers the determination of metal elements in purified terephthalic acid (PTA) by inductively coupled plasma atomic emission spectrometry (ICP-AES).This method is applicable to PTA samples containing sodium, chromium, cobalt, aluminum, titanium, potassium, magnesium, manganese, iron, nickel, molybdenum and calcium over 0.055 mg/kg, respectively.