Polyaniline-modified natural fibers have been recognized as promising candidates for conductive clothes, UV protection, and electromagnetic interference shielding. Hence, the purpose of this study was to investigate the effect of surface deposition of cotton fibers using polyaniline via in situ polymerization, and preceding structural changes were further screened by FT-IR, UV-Vis, TGA, SEM/EDX, and conductivity in comparison with bare cotton fibers used as the control sample. Polyaniline was introduced on the surface of cotton fibers as a conductive form, which was confirmed by electrical conductivity (1.54 × 10−4 Scm−1) equivalent to semiconductor materials. Detection of particular peaks at NKα 0.379 keV and ClKα 2.621 keV from EDX analysis revealed the introduction of nitrogen and chlorine, respectively. Polyaniline deposition on the cotton surface was successful to introduce hydrophobic environment to the system to enhance resistance to water absorption meaningfully.
Supramolecular solvents with restricted access properties (SUPRAS-RAM) are proposed as a new approach for integrating extraction and sample cleanup in the quantification of benzodiazepines in urine by liquid chromatography tandem mass spectrometry (LC-MS/MS). The SUPRAS-RAM was synthesized in situ in the urine by the addition of 1- hexanol (154 µL) and THF (600 µL). Benzodiazepines extraction was driven by both hydrogen bonds and dispersion interactions. Removal of proteins and polar macromolecules was performed by the action of the SUPRAS through chemical and physical mechanisms. Phospholipids were removed by precipitation during SUPRAS extract evaporation. A multivariate method was used for the optimization of the extraction process by applying Box-Behnken response surface design. The proposed method was validated according to the guiding principles of the European Commission Decision (2002/657/EC). Method detection and quantification limits for the target benzodiazepines were in the intervals 0.21-0.85 ng/mL and 0.67-2.79 ng/mL, respectively. The repeatability and reproducibility (expressed as relative standard deviations) were in the range 2-6 % and 3-8%, respectively. The method enabled the simultaneous extraction of benzodiazepines (recoveries in the range 84-105%) and the removal of matrix effects. The method was applied to the analysis of 13 urine samples using external calibration. Five out of 13 samples tested positive in alprazolam and lorazepam at concentrations in the range 5.4-74 ng/mL. The method allows simple and quick sample treatment with minimal solvent consumption while delivering accurate and precise data.
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