Investigation of Atmospheric Pressure Photochemical Ionization Mass Spectra of Binary Organic Solutions without Their Separation in Dependence on the Concentration of Solutions and Analyte Vapors in Nitrogen Using the Exponential Dilution Method and a Time-of-Flight Mass Spectrometer with an Atmospheric Pressure Photochemical Ionization Ion Source

The study is devoted to the investigation of atmospheric pressure photochemical ionization mass spectra of binary organic solutions of a small set of the analytes (dibutyl ether, propyl acetate, amyl acetate) in the same solvent (acetone) in the vapor phase and in a nitrogen flow without their separation in dependence on the analyte concentration in the solution and in nitrogen. The study was carried out using a custom-made time-of-flight mass spectrometer combined with a custom-made atmospheric pressure photoionization (APPhI) ion source coupled to an exponential dilution flask. Solvent vapor concentration in the nitrogen flow was 10 –1 –10 –4 %. Analyte concentration in the same flow was 10 –3 –10 –6 %. Exponential dilution was carried out using a heated exponential dilution flask with a magnetic stirrer. The temperature of the flask, glass transfer line to the APPhI ion source, and of the ion source itself was 80°С. It was shown that, at the initial acetone and analyte concentrations in nitrogen equal to 10 –1 and 10 –3 %, respectively, mass spectra of the solution vapors contained peaks of ions, such as [M–H] + , M •+ , [M + H] + , [2M + H] + , [M + Mа • + H] + , [Mа + H] + , and [2Mа + H] + . When acetone and analyte concentrations in nitrogen were equal to 10 –3 and 10 –6 %, respectively, mass spectra of each analyte revealed mainly peaks of the [M–H] + ion for dibutyl ether and amyl acetate and peaks of [2M + H] + and M •+ ions for propyl acetate.