This International Standard specifies two methods for the determination of the oil content non volatile at about 105 °C, of liquefied anhydrous ammonia for industrial use, namely: — a gravimetric method; — an infra-red spectrometric method. The gravimetric method is applicable to products having an oil content equal to or greater than 10 mg/kg. The infra-red spectrometric method, being more sensitive, is applicable to products having an oil content greater than 1 mg/kg.