ABSTRACT
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 0.07-0.94â¯ngâ¯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.
ABSTRACT
A high throughput, and eco-friendly method based on solid-phase microextraction (SPME) combined with direct analysis in real time mass spectrometry (DART-MS) was established for the determination of trace pollutants in water. A laboratory-made SPME device coated with a metal organic framework (MIL-100 (M)) was fabricated for the on-site enrichment of triazine herbicides in environmental water, and the device was directly subjected to DART ionization (<20â¯s) for high resolution MS. The interactions between the target analytes and sorbents were investigated to improve the SPME device targeting specific pollutants, as well as to improve the desorption and ionization processes with DART-MS. Other factors were also systematically studied to obtain the optimal conditions, including pH, salinity, extraction temperature, pressure at the Vapur® interface, linear rail moving speed, gas temperature, extraction time, and sample volume. The limit of detection of target compounds were 5.0-50.0â¯ngâ¯L-1 and the recoveries ranged from of 92.4%-125.7%.
ABSTRACT
A mechanochemical magnetic solid phase extraction (MCMSPE) method was developed for a one-pot extraction and enrichment of organochlorine pesticides in tea leaves to demonstrate the advantage of using magnetic nanoparticles in the sample preparation process. The enriched analytes were subsequently detected by ultra-high performance liquid chromatography and gas chromatography mass spectrometry. The presence of magnetic metal-organic-framework (MMOF) (Fe3O4@MIL-100 (Fe)) nanoparticles help to rupture the cell walls in solid plant samples more thoroughly, and at the same time, act as a selective sorbent for the enrichment of target analytes. Compared to traditional methods, this approach significantly shortens the sample processing time from tens of minutes to tens of seconds. The parameters of the procedure were systematically studied and optimized to achieve good limits of detection (0.62-3.92â¯ngâ¯g-1, LOD S/Nâ¯=â¯3), significantly improved recoveries (81.46-113.59%), and good reproducibility (RSD 2.63-9.87%, nâ¯=â¯5). The results indicated that this method can be applied for high throughput determination of organochlorine pesticides in tea leaves, and can be used for other dried plant samples.
