This method is for determining the concentration of sodium (Na) as dissolved and suspended sodium compounds in liquefied petroleum gas (LPG) in the range of 0.1 to 10 mg/kg (mass-ppm) sodium. After sample preparation, either Inductively Coupled Plasma –, Optical Emission Spectroscopy (ICP-OES, or ICP) or Atomic Adsorption Spectroscopy (AAS) can be utilized to determine the sodium concentration.