Ethyl nonanoate is separated and quantified from cachaca, rum and whisky by direct injection gas chromatography spectrometry[1]. It is used as the internal standard to monitor the solid-phase micro-extraction fibre extraction integrity and efficiency. Ethyl nonanoate is separated and quantified from cachaca, rum and whisky by direct injection gas chromatography spectrometry[1]. It is used as the internal standard to monitor the solid-phase micro-extraction fibre extraction integrity and efficiency.