Sorbent and solvent co-enhanced direct analysis in real time-mass spectrometry for high-throughput determination of trace pollutants in water

A sorbent and solvent co-enhanced direct analysis in real-time mass spectrometry (SSE-DART-MS) method was developed for high-throughput determination of trace pollutants in water. The use of sorbent for pre-concentration and solvents for assisting desorption and ionization synergistically enhanced the signals from the trace pollutants detected by DART-MS. Phthalic acid esters (PAEs) were used as model analytes to validate the SSE-DART-MS method. Graphitic carbon nitride (g-C3N4)-based materials with two morphologies and six organic solvents were used to systematically evaluate the enhancement effect by the sorbent and solvent. A better analytical performance was achieved with the two-dimensional (2D) g-C3N4, compared to three-dimensional (3D) g-C3N4/C, indicating that the morphologies of sorbents played a key role in SSE-DART-MS analysis. The MS signals of ail the analytes were increased by 14-100 times for the two materials in the presence of the selected solvents. With the SSE-DART-MS method, concentration limits of detection for water samples in the range 0.07-0.94 ng L-1, and recovery in the range 82.8-119% using g-C3N4, were obtained for the PAEs. This work not only provides a reliable method for the coupling of solid phase extraction technique with DART-MS, but also presents valuable information for conducting other DART-MS analyses.