This method is for determining trace oxygenated components in high purity polymer grade ethylene and propylene gas or liquid using a gas chromatograph equipped with a mass spectrometer run in selected ion monitoring mode. The specific instrument is preconfigured and is capable of determining typical impurities in polymer grade ethylene or propylene, however this method only outlines the procedure for determining the specific oxygenates 2-butanol, acetone, acetaldehyde, ethanol, isopropanol, methanol, methyl tert-butyl ether, n-propanol, n-butanol and tert-butanol. Some components co-elute but are readily extracted by unique ions. The lower limit of quantitation for each component is 0.05 mol-(or mass-) ppm.