This study was undertaken to determine whether electrospray ionisation could be used to screen and quantify the various alkaloids present in illicit heroin samples in a matter of minutes. Current analytical methods required half an hour for initial screening and at least a further two hours for quantitation.
Samples analysed included authentic standards and material from seizures. All solutions were made in 50% methanol/water, acidified with 1% acetic acid. The solutions were infused directly into the electrospray ion source. Resulting spectra contained a peak for each species at M+1. No significant fragmentation was observed for any of the analytes.
For two component mixtures, Kebarle and Tang [1] have observed the ionisation efficiency (i.e., yield of ions per unit of concentration) depends strongly on the concentration and nature of other ionisable species in the solution and weakly on total concentration of ionised species. The model which was developed by these authors to predict the observed ion yields is being extended in this project to many components. Initial results from experiments to test the extended model for quantitative ESMS will be presented in this paper.