This standard specifies a method for the determination of lead in antimony and antimony trioxide using flame atomic absorption spectroscopy (AAS) for samples with a lead content in the range of 0.0020% to 0.75%. The standard details Sample Handling, reagent preparation, and measurement procedures to ensure accuracy and conformity of results. Absorbance measurement of lead at specific wavelengths in a dilute muriatic acid medium enables accurate analysis of lead content in samples using an air-acetylene flame.