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Chitosan (CTS) modified magnetic nanoparticles (CTS@Fe3O4 MNPs) offer dual functions for the detection of surfactants using surface enhanced laser desorption/ionization mass spectrometry (SELDI-MS). The characterization of CTS@Fe3O4 MNPs is carried out using X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy, and UV-vis absorption. CTS@Fe3O4 magnetic nanoparticles offer a simple separation method for surfactants. CTS@Fe3O4 MNPs show an absorption band at 337 nm that matches the laser wavelength of the N2 laser. The material provides dual functionalities; as a probe and for surface enhanced LDI-MS. Analysis of surfactants using CTS@Fe3O4 MNPs shows a remarkable limit of detection, offers high throughput analysis and fast separation (<5 min). Compared to a conventional organic matrix (2,5-DHB), the spectra obtained using CTS@Fe3O4 MNPs …

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Mass spectrometry (MS) provides a simple discrimination method for microorganisms. However, the presence of species such as melanin in fungal spores of Aspergillus niger (melanotic fungal) suppress ionization for matrix assisted laser desorption/ionization mass spectrometry (MALDI-MS). Inhibition of melanin synthesis pathways by tricyclazole enhances mycelium growth and protein contents of Aspergillus niger for four different media; namely sabouraud dextrose agar medium (SDA), potato dextrose agar (PDA), czapek dox agar (CDA) and yeast extract agar (YEA) media. The cell contents of protein and mycelium growth of Aspergillus niger are increased with the addition of a low concentration of tricyclazole (25–50 mg L−1). Furthermore, it improves the ionization signals of A. niger for MALDI-MS. This study reveals that inhibition of melanin using tricyclazole leads to the increase of protein content, mycelium …

Graphene oxide (GO) was synthesized and used as a coagulant of rare earth elements (REEs) from aqueous solution. Stability and adsorption capacities were exhibited for target REEs such as La(III), Nd(III), Gd(III), and Y(III). The parameters influencing the adsorption capacity of the target species including contact time, pH, initial concentration, and temperature were optimized. The adsorption kinetics and thermodynamics were studied. The method showed quantitative recovery (99%) upon desorption using HNO3 acid (0.1 M) after a short contact time (15 min).

Analysis of quinidine for fish tissues using single drop microextraction (SDME) coupled with atmospheric pressure matrix assisted laser desorption/ionization mass spectrometry (AP-MALDI-MS) are reported. Optimization conditions; such as extraction solvent, extraction time, pH of the aqueous solution, salt additions (NaCl), stirring rate, matrix type and concentration are investigated. Linear dynamic range (µM), limit of detection, relative recovery%, and enrichment factor are 0.08-9.2, 0.05, 94.8±3.1-98.5±3.3%, 4.34±0.28-4.40±0.30, respectively. SDME-AP-MALDI-MS shows good intraday and interday reproducibility.

The applications of organic matrices for matrix assisted laser desorption/ionization mass spectrometry (MALDI-MS) are reviewed. Recent advances of MALDI-MS using organic matrices, including the applications of ionic liquids matrices (ILMs) and organic matrices modified/conjugated nanoparticles, are covered. Organic matrices are applied for many other applications such as derivatization or capping agents of nanoparticles, eluent for chromatography, internal standard for quantitative analysis and as reagents for the synthesis of eco-friendly solvents (ILMs). Within the field of nanotechnology, organic matrices@nanoparticles have a dominant position, and the last decade has seen remarkable growth for these hybrid materials. Selection of the optimum organic matrices is paramount important and critical for the analysis using MALDI-MS. Factors such as additives, instrument set up and sample preparation affect …

Laser desorption-ionization mass spectrometry (LDI-MS) is used to determine Hg(II) ions by using thymine-modified chitosan-coated magnetic nanoparticles (TCTS). TCTS nanoparticles are characterized using transmission electron microscopy, X-ray diffraction, UV-vis absorption, infrared spectroscopy and LDI-MS. TCTS acts as a preconcentration probe, supports surface enhanced LDI-MS (SELDI-MS) and acts as a capping agent for Hg(II). The separation of Hg(II) via this method combined with SELDI-MS provides a sensitive and selective tool for inexpensive and fast (5 min) detection of Hg(II) with limit of detection down to 0.05 nmol for environmental samples such as tap and sea water.

A trimethylamine (TEA)-assisted synthesis approach that combines the preparation of hierarchical porous zeolitic imidazolate framework ZIF-8 nanoparticles and one-pot encapsulation of target molecules is presented. Two dye molecules, rhodamine B (RhB) and methylene blue (MB), and one protein (bovine serum albumin, BSA) were tested as the target molecules. The addition of TEA into the solution of zinc nitrate promoted the formation of ZnO nanocrystals, which rapidly transformed to ZIF-8 nanoparticles after the addition of the linker 2-methylimidazole (Hmim). Hierarchical porous dye@ZIF-8 nanoparticles with high crystallinity, large BET surface areas (1300–2500 m2/g), and large pore volumes (0.5–1.0 cm3/g) could be synthesized. The synthesis procedure was fast (down to 2 min) and scalable. The Hmim/Zn ratio could be greatly reduced (down to 2:1) compared to previously reported ones. The surface …

In most applications of quantum dots (QDs) for surface-assisted laser desorption/ionization mass spectrometry (SALDI-MS), one side of QDs is supported by a solid substrate (stainless - steel plate), whereas the other side is in contact with the target analytes. Therefore, the surface capping agent of QDs is a key parameter for laser desorption/ionization mass spectrometry (LDI-MS). Cadmium telluride quantum dots (CdTe QDs) modified with different capping agents are synthesized, characterized, and applied for surface tuning laser desorption/ionization mass spectrometry (STLDI-MS). Data shows that CdTe quantum dot modified cysteine (cys@CdTe QDs) has an absorption that matches with the wavelength of the N2 laser (337 nm). The synergistic effect of large surface area and absorption of the laser irradiation of cys@CdTe QDs enhances the LDI-MS process for small - molecule analysis, including α-, β …