Poly(phenyl-(4-(6-thiophen-3-yl-hexyloxy)-benzylidene)-amine) (P3TArH) was successfully synthesized and coated on the surface of Fe₃O₄ magnetic nanoparticles (MNPs). The nanocomposites were characterized by Fourier transform infra-red (FTIR), X-ray diffractometry (XRD), Brunauer-Emmett-Teller (BET) surface area analysis, analyzer transmission electron microscopy (TEM) and vibrating sample magnetometry (VSM). P3TArH-coated MNPs (MNP@P3TArH) showed higher capabilities for the extraction of commonly-used phthalates and were optimized for the magnetic-solid phase extraction (MSPE) of environmental samples. Separation and determination of the extracted phthalates, namely dimethyl phthalate (DMP), diethyl phthalate (DEP), dipropyl phthalate (DPP), dibutyl phthalate (DBP), butyl benzyl phthalate (BBP), dicyclohexyl phthalate (DCP), di-ethylhexyl phthalate (DEHP) and di-n-octyl phthalate (DNOP), were conducted by a gas chromatography-flame ionization detector (GC-FID). The best working conditions were as follows; sample at pH 7, 30 min extraction time, ethyl acetate as the elution solvent, 500-µL elution solvent volumes, 10 min desorption time, 10-mg adsorbent dosage, 20-mL sample loading volume and 15 g·L-1 concentration of NaCl. Under the optimized conditions, the analytical performances were determined with a linear range of 0.1⁻50 µg·L-1 and a limit of detection at 0.08⁻0.468 µg·L-1 for all of the analytes studied. The intra-day (n = 7) and inter-day (n = 3) relative standard deviations (RSD%) of three replicates were each demonstrated in the range of 3.7⁻4.9 and 3.0⁻5.0, respectively. The steadiness and reusability studies suggested that the MNP@P3TArH could be used up to five cycles. The proposed method was executed for the analysis of real water samples, namely commercial bottled mineral water and bottled fresh milk, whereby recoveries in the range of 68%⁻101% and RSD% lower than 7.7 were attained.
In this work, chitin (Ch) was chemically extracted from wild mushrooms and then grafted to polyaniline (PANI) to form a composite (Ch-g-PANI) to detect ammonia (NH3) gas. The Ch-g-PANI was comprehensively characterized using Scanning electron microscopy (SEM), elemental mapping, thermogravimetric analysis (TGA), and Fourier transform infrared spectroscopy (FTIR) and UV-Vis spectroscopy. The NH3 gas detection optimization was evaluated using Box-Behnken Design. Typically, physical factors such as (A)film layer, (B)loading %, and (C)contact time were investigated and validated through the analysis of variance (ANOVA). The ANOVA revealed that dual interactions between (A)film layer - (C)contact time, and (B)loading % - (C)contact time are among the significant factors. By considering these significant interactions, the highest sensitivity was obtained when (A)film layer (3), (B)loading (5 %), and (C)contact time (10 min) in NH3 gas detection. Then, the optimized Ch-g-PANI was tested in the linear range of NH3 gas concentration from 10 to 50 ppm, which resulted in a linear calibration curve with R2 = 0.994 and a detection limit of 15.03 ppm. Sensor performances showed that Ch-g-PANI films possess high selectivity for NH3 gas among the common interfering gases and the film can be reused for up to 6 cycles. Therefore, the new mushroom-sourced Ch-g-PANI is an inexpensive and economical sensor in the NH3 gas sensor field.