FIELD: chemistry.
SUBSTANCE: invention relates to methods of ion exchange, as well as to a method and system for detecting nitrates. In one aspect, the present invention provides an ion exchange method for forming an analysed negative ion nitrate-dopant additive for analysis using a spectrometric analysis apparatus, comprising: providing a gas containing a dopant in both neutral and ionised forms; bringing the sample-containing nitrate into contact with a gas containing the dopant, and thereby desorbing the nitrate ion from the sample to form an analysed negatively charged nitrate-doping anion and substitution of the desorbed nitrate ion by the negatively charged ionised molecule of the doping additive, where the dopant is an organic compound containing two or more carbon atoms and two or more functional groups capable of forming a simultaneous convergent hydrogen bond with the nitrate ion, or the dopant is an organic compound containing at least two carbon atoms and only one functional group capable of forming a hydrogen bond with the nitrate ion, which is a -COOH functional group, and the carbon atom of the functional group -COOH is bonded directly to the other carbonyl group, provided that the dopant is not lactic acid, a salt of lactic acid or a compound which forms lactate ions after ionisation.
EFFECT: invention is intended for desorption of nitrate ions from a sample during ion exchange with formation of analysed ion nitrate-doping additive which can be registered by means of a device for spectrometric analysis.
47 cl, 3 dwg
