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 preconcentration 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 all the analytes were increased by 10–100 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.