Silver-needle-based solid phase microextraction coupled with constant flow desorption ionization for obtaining...

Accurate mass spectrometric analysis of the emerging pollutant 1,2-bis(2,4,6-tribromophenoxy) ethane (BTBPE) remains significantly challenging due to the difficulty in generating its molecular or quasi-molecular ions. This study developed a novel technique termed silver-needle-based solid-phase microextraction constant flow desorption ionization mass spectrometry (silver-needle-based SPME-CFDI-MS) for the highly efficient ionization and detection of BTBPE. By utilizing the silver needle as both a solid-phase microextraction fiber and a corona discharge electrode, this method enables preconcentration of BTBPE from water samples, followed by its desorption, ionization, and detection via CFDI-MS. During the CFDI process, corona discharge on the silver needle produces Ag⁺, while the flowing solvent desorbs BTBPE from its surface, resulting in the formation of BTBPE quasi-molecular ions ([BTBPE + Ag]⁺). The characteristic mass and tandem mass spectra of BTBPE were subsequently acquired. Under optimized parameters, the limit of detection for BTBPE reached 21 ng L^-1, with a linear range from 0.10 to 3.5 μg L^-1 (R² > 0.9969). The intra-day (n = 8, c = 0.5 μg L^-1) and inter-day (n = 3 per day for 5 days, c = 1.0 μg L^-1) precision values were 9.2 % and 16.4 %, respectively. The method was successfully applied to detect trace BTBPE in real river water and soil samples, with spike recoveries of 80-120 % demonstrating its accuracy and practicality for environmental analysis.