Thermodynamic Simulation of the Composition of the Major Background Ions in Low-Temperature (“Cold”) Inductively Coupled Plasma

The study considers a possibility of studying the manifestation of the major background ions derived from the main elements (H, N, O, and Ar) of inductively coupled plasma under low-temperature (“cold”) plasma conditions through thermodynamic simulation. These ions, known to induce significant spectral interferences, are always observed when aqueous samples are injected into inductively coupled plasma mass spectrometers (ICP–MS). Using thermodynamic simulation in the temperature range from 2000 to 5000 K, the quantitative composition of the major background ions in ICP–MS was determined as a function of plasma temperature. A comparison of the theoretical calculations and experimental data from mass spectral measurements of the major background ions was conducted, revealing a high degree of correlation between the two sets of the results. This agreement between the calculations and experiments confirms the validity of the thermodynamic model used for thermochemical processes in ICP–MS and its applicability to subsequent calculations in addressing analytical challenges. Additionally, a method is proposed for the unambiguous evaluation of the gas kinetic temperature of the plasma, while simultaneously considering practically all major background ions.