A mass-spectrometric study of the aqueous solutions of opiates with their ionization in a collison nebulizer

Abstract

It was found that the use of a Collison nebulizer as an ionization source for the mass-spectrometric analysis of the aqueous solutions of opium alkaloids makes it possible to determine opiates with the limits of detection of 8.8 × 10^–9, 8.83 × 10^–8, 1.6 × 10^–7, and 3.5 × 10^–8 M for papaverine, codeine, heroin, and morphine, respectively. The dependence of mass-spectrometric responses [(M + H)⁺ ions] on the concentrations of these compounds in water in a range from 10^–8 to 10^–3 M appears as a curve with a maximum; this is explained by the consideration of the most probable mechanisms of the ionization of drops on liquid spraying in a Collison nebulizer (a model of the destruction of a double electrical layer and a model of statistical fluctuations, which is also known as a model of symmetrical charging). The transformation of the mass spectrum of a mixture (1: 1: 1: 1) of morphine, codeine, papaverine, and heroin was studied on varying the concentration of this mixture in aqueous solution. Two samples of opium of Central-Asian origin were analyzed to test the applicability of ionization in a Collison nebulizer to the analysis of real test materials.