Improvement of vacuum nebulizing interface for direct coupling micro-liquid chromatograph with mass spectrometer and some applications to polar natural organic compounds

A vacuum nebulizing interface for direct coupling a micro-liquid chromatograph (LC) with a mass spectrometer (MS) was improved by incorporating a small water cooling jacket and a bubble saturator for the nebulizing gas. By this improvement the applicability of the micro-LC-MS system was remarkably extended to various non-volatile polar organic compounds such as adenosine, tryptophane, glycyl-glycyl-glycine, mono- and di-saccharides, etc. The desirable temperature profile around the nebulizing tip was also discussed.