ROTATING BALL INLET FOR CONTINUOUS MASS-SPECTROMETRIC MONITORING OF AQUEOUS-SOLUTIONS

A new device for continuous mechanical introduction of liquid samples into a mass spectrometer is described. A ball mounted on a shaft is su pported by a polymer gasket at the circumference of a hole leading int o the mass spectrometer. The surface of the ball on the outside is in contact with the liquid sample. Sample sticking to the surface of the ball is dragged past the gasket into the mass spectrometer where it ev aporates and is ionized by electron impact. The rotating ball inlet ov ercomes some of the problems associated with previously known methods for continuous sample introduction into a mass spectrometer. A wide va riety of compounds can be measured continuously in aqueous solution wi th a response time in the order of seconds. The fragmentation of molec ules caused by electron impact ionization facilitates identification o f analytes. (C) 1998 John Wiley & Sons, Ltd.