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Raman spectroscopy and surface enhanced Raman spectroscopy (SERS) are expanding their horizons into widespread applications as analytical tools with immense potentials. In the current work, we demonstrated the use of a portable Raman system conjugated with graphene enhanced Raman spectroscopy (GERS) for assessing the freshness of fruits and vegetables. Dual nano-platforms have been used involving the use of gold/silver nanoparticles seeded graphene sheets (Au@G and Ag@G, respectively) as the SERS system for probing the freshness of fruits and vegetables. The data showed that Au@G offered high sensitivity, high resolution and high biocompatibility. A novel and simple GERS method based on a microdrop of Ag@G or Au@G on the fruit surface was used for the evaluation of the freshness of the fruits/vegetables. Fruits and vegetables like Wax apple, Lemon, Tomato, Red Pepper and Carrot …

Applications of ionic liquids (ILs) for mass spectrometry (MS) are a burgeoning area and are promising for real applications. However, the research of ILs for MS is in its infancy and there are a large potential for further applications under the ashes. This review article provided an overview of the current state and the research progress of ILs applications for MS. ILs offered several advantages, such as low vapor pressure, soft ionization, high sensitivity, better separation and microextraction, effectively disperse nanoparticles for nanoprobe technologies, and stable under vacuum and for storage in solution form, that leaded to several applications for MS and assured that ILs carry a brilliant future for analytical purposes. A plethora of ILs with different properties can be designed by various combinations of acid and base moieties and were applied as multifunctional materials. Thus, ILs provided many platforms such as …

A novel zinc-based luminescent metal–organic framework (Zn-MOF) has been successfully constructed based on a designed flexible and electron-rich N-involved linker (HL = 4-(bis(4-(pyridin-4-yl)phenyl)amino)benzoic acid). The framework of this Zn-MOF exhibits a 2-fold interpenetrated network which is composed of (3,3)-c sheets. The Zn-MOF has a strong solid state emission at 512 nm. The luminescence signal of the Zn-MOF can be quenched efficiently by trace amounts of electron-deficient nitroaromatics, especially 2,4,6-trinitrophenol (TNP). The quenching constant (Ksv) for TNP is 2.11 × 104 M−1, indicating that this framework can be employed as an excellent chemical sensor for identifying and quantifying TNP. This work highlights a strategy for designing a N-involved π-electron-rich enhanced ligand with nucleophilic properties for MOF-based materials as sensors. It also paves the way toward exploring …

Rationale
Investigation of nanoparticles for laser desorption/ionization mass spectrometry (LDI‐MS) is routinely reported. However, the effect of surface capping of nanomaterials for LDI‐MS is not well studied.
Methods
Different capping agents of quantum dots (CdTe) affect the spectra quality and sensitivity of protein analysis and protein digestion using trypsin enzyme assisted by microwave. Surface modification of CdTe quantum dots with different capping agents, namely 3‐mercaptopropionic acid (3‐MPA), 4‐aminothiophenol (4‐ATP), 4‐mercaptobenzoic acid (4‐MBA), 11‐mercaptoundecanoic acid (11‐MUA), cysteine (Cys) and thioglycolic acid (TG), were investigated for quantum dots (QDs)‐assisted trypsin protease followed by analysis using mass spectrometry.
Results
CdTe QDs were used as a surface to assist trypsin protease and laser desorption/ionization mass spectrometry (surface‐assisted laser …

Gold nanoparticles (AuNPs) assisted laser desorption/ionization mass spectrometry (GALDI-MS) provided new horizons and offered many functions for various applications. This review summarized AuNPs applications for analytical, biotechnology and proteomics. AuNPs efficiently absorbed the laser radiation and transferred the energy to the analyte for the desorption/ionization process. The unique features of AuNPs such as large surface area and high absorption coefficient lead not only to high resolution, low interference and low limit of detection, but also offered selective detection for certain species. AuNPs provided an excellent surface for the analysis of several species such as small molecules, biomarkers, proteins and cells (pathogenic bacteria or cancer cells). AuNPs played many roles such as surface for LDI-MS, probe and stationary phase for separation or preconcentration. AuNPs modified …

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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 …