Applications of ambient electric arc ionization mass spectrometry in saline samples

Salinity tolerance of ambient electric arc ionization (AEAI) was evaluated by comparing electrospray ionization for various samples at NaCl concentrations from 0 to 10 00 mmol/L. AEAI-mass spectrometry (AEAI-MS) exhibited an excellent signal intensity even at NaCl concentrations of 1000 mmol/L, while the ESI-MS had no signal because high salinity has a strong inhibitory effect on analytes. The sodium adduct was verified using LiCl instead of NaCl. AEAI-MS successfully quantified saline samples with an excellent quantitative ability (R-2 >= 0.998). We also achieved some analytical samples in the buffer solution at a very high concentration and even in a saturated salt solution. Overall, AEAI-MS has protonated ions for most target analytes. In addition, the relationship between auxiliary temperature and the distance from the sample to the arc was investigated, and the results indicated that thermal desorption plays an important role in AEAI source. (C) 2021 Published by Elsevier B.V. on behalf of Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences.