A new and sensitive analytical method, using capillary liquid chromatography (capLC) with a microfabricated heated nebulizer chip for atmospheric pressure photoionization and tandem mass spectrometry (μAPPI-MS/MS), was developed for the analysis of selected carbamate pesticides in a tomato matrix. The performance of the instrumental method was evaluated, using seven pesticides, namely oxamyl, methomyl, aldicarb, carbofuran, pirimicarb, thiocarb, and ditalimfos. The limits of detection achieved with the capLC-μAPPI-MS/MS method in the positive ion mode were low, ranging from 0.25 ng mL(-1) for pirimicarb to 5 ng mL(-1) for oxamyl and methomyl, corresponding to 5 and 0.25 μg kg(-1) for tomato samples, respectively, which are clearly below the maximum residue limits for them in fruits and vegetables. The repeatability of the instrumental method ranged from 2.9 to 13.9% (RSD) at a low (0.05 μg mL(-1)) concentration level. An adequate linearity (r(2)=0.984-0.999) at a concentration range from 0.005 to 5.0 μg mL(-1) was observed for all pesticides. The results obtained show that the capLC-μAPPI-MS/MS method developed could be used for the analysis of selected pesticides from tomato.
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http://dx.doi.org/10.1016/j.aca.2011.04.006 | DOI Listing |
J Colloid Interface Sci
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Department of Chemical, Materials and Production Engineering, University of Naples Federico II, Italy.
Hypothesis: Bubbles oscillating near a free surface are common across numerous systems. Thin liquid films (TLFs) formed between an oscillating bubble and a free surface can exhibit distinct morphological features influenced by interfacial properties, evaporation, and deformation history. We hypothesize that a continuous film presence throughout oscillation results in a wimple morphology, whereas intermittent film presence leads to a dimple formation.
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College of Food Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
In the oil dispersion of chitosan, the formation of a capillary bridge was triggered by adding a small amount of water to obtain an oleogel. With this method, the types of liquid oil and the ratio of oil/chitosan/water were explored to achieve an optimal oleogel. MCT performed best, followed by soybean oil, which was chosen for its edibility and cost.
View Article and Find Full Text PDFSe Pu
January 2025
West China School of Pharmacy, Sichuan University, Chengdu 610041, China.
Ambient mass spectrometry imaging (MSI) enables hundreds of analytes in tissue sections to be directly mapped at atmospheric pressure with minimal sample preparation. This field is currently experiencing rapid growth, with numerous reported ambient ionization techniques resulting in a "hundred flowers bloom" situation. Nanospray desorption electrospray ionization (nano-DESI), developed by the Laskin group in 2010, is a widely used liquid-extraction-based ambient ionization technique that was first used for mass spectrometry imaging of tissue in 2012.
View Article and Find Full Text PDFACS Appl Mater Interfaces
December 2024
Centre for MicroElectroMechanical Systems (CMEMS), University of Minho, Azurem Campus, 4800-058 Guimaraes, Portugal.
The World Health Organization (WHO) reports 684,000 deaths/year due to slips and falls (SFs), with ∼38 million people requiring medical attention per annum. In particular, SFs on ice surfaces account for 45% of all SF incidents, costing over $100 billion globally in healthcare, intensive care, and insurance expenses. Current antislip solutions focus on hydrophobicity to repel interfacial fluids, aiming to maintain solid-to-solid contact.
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December 2024
Department of Chemistry, National Demonstration Centre for Experimental Chemistry Education, Yanbian University, Yanji City 133002, Jilin Province, China.
Generally, the traditional stationary phase for liquid chromatography is the key part, but with an in situ immutable property, leading to many separation limitations. Based on the former exploration of photosensitive gas chromatography, we successfully prepared a photosensitive monolithic capillary silica column with high light transmission, taking advantage of the reversible cis-trans isomerism of azobenzene. And the cis-trans isomerism has launched an effective, reversible, and precise control on the liquid chromatographic retention behavior just by photoinduction according to the theoretical basis of a good correlation between photoinduction time, -azobenzene ratio, and chromatographic retention factor () ( > 0.
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