Time-of-flight mass spectrometry (TOFMS) has recently been introduced as an
alternative to scanning-based mass analyzers for use in elemental analysis
. Coupled with an inductively coupled plasma or alternative ion source, TOF
MS can produce a complete atomic mass spectrum in less than 50 ys. Because
of this high spectral-generation rate, even very brief transient signals ca
n be recorded with high fidelity. Furthermore, each mass spectrum is derive
d from the same sub-microsecond pulse of ions, so high precision can be ach
ieved by using either isotope-ratioing or internal standardization techniqu
es. All these features make TOFMS attractive for the measurement of transie
nt signals, such as those commonly encountered in speciation analysis. In t
his paper, the capabilities of TOFMS in speciation will be demonstrated thr
ough the coupling of pas chromatography and capillary electrophoresis with
an inductively coupled plasma-TOFMS. Additionally, the development of novel
switched gas sampling glow discharge (GSGD) ionization sources will be des
cribed and their role in chemical speciation will be evaluated. The switche
d GSGD has the ability to collect both atomic and molecular mass spectra in
rapid succession, to provide additional information about chemical species
. The coupling of various sample introduction systems (flow-cell, exponenti
al dilutor, capillary gas chromatography and electrothermal vaporization) t
o the GSGD is outlined. (C) 2000 Elsevier Science B.V. All rights reserved.