Electrospray mass spectrometry as a technique for the elemental analysis of metals and organometals

An investigation of an in-house constructed electrospray (ES) ion source and interface has been carried out with the focus on elemental analysis. An evaluation of the 29, 30 and 31 gauge capillary sizes for the ES source is presented. For multielement solutions of alkali metals, alkaline earth metals and transition metals studied in the bare metal ion mode, the smaller 30 gauge capillary improved the detection limits by an order of magnitude over those of the larger 29 gauge. The 31 gauge was too fragile for easy handling. The ion-cluster modes of Cr-II, Cr-III and Co-II were investigated and the resulting spectra indicate the possibility of attaining speciation information with this set-up. Matrix effects on the analyte signal of a multielement solution of transition metals using the 29 and 30 gauge capillaries are discussed. The same trend is observed with both capillaries where the signal intensity improves with the addition of 0.15% and 0.30% total dissolved solids. At higher concentrations of total dissolved solids signal suppression is seen. Additionally, ES-MS was demonstrated as an elemental analysis tool for the study of the bare metal ion mode of larger organometallics, mainly organolead compounds and metalloporphyrins.