As a member of the metal phosphorus trichalcogenide family, MPS₃ is widely used in nonlinear optics and devices, which can be regarded as a significant benefit for the excellent photonic and optoelectronic properties. In this work, the MnPS₃ nanosheet is prepared by the chemical vapor transport method and the MnPS₃ saturable absorber is demonstrated by modifying mechanical exfoliation. To the best of our knowledge, the dual-wavelength self-starting mode-locking erbium-doped fiber laser with MnPS₃ saturable absorber is demonstrated for the first time. The dual wavelength mode-locked laser with a pulse repetition rate of 5.102 MHz at 1565.19 nm and 1565.63 nm is proposed. Its maximum output power at the dual-wavelength is 27.2 MW. The mode-locked laser can self-start and stably run for more than 280 h.

A method using liquid-liquid extraction (LLE) followed by clean-up steps of centrifugation, freezing and dispersive solid phase extraction (D-SPE) and ultra-performance liquid chromatography (UPLC) coupled with tandem mass spectrometry (MS/MS) has been devel- oped for the determination of trace levels of 104 pesticides in vegetable oils. LLE has been optimized to extract these pesticide residues from oils to obtain the highest recoveries of pesticides and the lowest co-extract fat residue in the final extract. In addition, the centrifugation and freezing steps as well as D-SPE with primary secondary amine (PSA), graphite carbon black (GCB) and C18 were used as the clean-up steps to minimize the co-extract fat. The recoveries obtained ranged from 55% to 121% and the relative standard deviations (RSDs) ranged from 0. 47% to 19. 2% at the spiked levels of 0.01, 0.02 and 0.05 mg/kg. This method, combining with accurate and sensitive detection, allowed quantification and confirmation at levels as low as 1 µg/kg for 80% of the analytes. The limits of quantification (LOQs) of the most compounds were below the maximum residue limits (MRLs) established by the Chinese legislations for oils. The proposed method was applied successfully for the residue determination of the selected pesticides in oils.