A New HPLC/MS System Equipped with a Supersonic Molecular Beam Sample Introduction System

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A new high performance liquid chromatography mass spectrometer system (HPLC/MS), equipped with a supersonic molecular beam sample introduction system (HPLC/SMB/MS) is described. Its performance characteristics are examined for alkyl amine compound as a test sample.1. Characteristics of HSI (Hyperthermal Surface Ionization) detection of organic molecules for HPLC :High polar solvents, such as water, methanol, and acetonitrile, are frequently used as mobile phase in reversed phase HPLC. They interact with solid surface of HSI detector, and affect its response characteristics. We examined these effects, using HPLC/HSI detector without mass analysis of formed ions. The tested combinations of mobile phase and solid surface are, (i) water/Iridium (Ir), (ii) water/Platinum (Pt), (iii) n-hexane/Pt, and (iv) methanol/Pt. The results obtained are summarized as below. (1) The mobile phase flow rate was tested as a function of, (i) signal response, (ii) noise level, and (iii) background level. A l … More arge interaction between solvent and solid surface was observed at mL/min order flow rate, whereas μL/min range had little effect to HPLC/HSI performance, for all of the solvents tested. (2) Sensitivity of around 1.0C/g was obtained for alkyl amine, using water/Ir system. (3) The minimum detectable amount of n-propylamine was the order of 10pg with water/Ir. (4) The dynamic range for water/Ir was around 104, with alkylamine. (5) The sensitivity for n-propylamine with water/Ir was 10 times greater than that with water/Pt. (6) Approximately the same response characteristics, as described in (1)〜(4), were obtained for the other solvent/surface system. It was concluded that high polar solvent can effectively be used as HPLC mobile phase for HSI operation. Acetonitrile has not been tested yet.2.HPLC/HSI/MS operation :The apparatus set up has been completed, and spectrum measurement has begun, under various operational conditions. They are (i) nozzle temperature, that is relevant to the molecular kinetic energy, (ii) solid surface temperature, (iii) HPLC flow rate, and (iv) the nature of the solvent. Using Ir and Pt as solid surface, (a) signal response, (b) noise level, and (c) background level, (d) dynamic range, are under examination now, and will be reported elsewhere. Less