This standard specifies a method for the determination of zinc content in tin-lead solder by flame atomic absorption spectroscopy (AAS), applicable to the determination of zinc content between 0.00025% and 0.0050%. The standard describes in detail the sample handling, reagent use, instrument conditions and measurement procedures. It is an arbitration analysis method for zinc content in tin-lead solder. The standard ensures the accuracy and repeability of the measurement results and is suitable for routine quality control and analysis in the laboratory.