Synthesis and Characterization of the Inclusion Complex of ß-cyclodextrin and Azomethine.

A ß-cyclodextrin (ß-Cyd) inclusion complex containing azomethine as a guest was prepared by kneading method with aliquot addition of ethanol. The product was characterized by Fourier Transform Infrared (FTIR) spectrometer, 1H Nuclear Magnetic Resonance (1H NMR) and Thermogravimetric Analyzer (TGA), which proves the formation of the inclusion complex where the benzyl part of azomethine has been encapsulated by the hydrophobic cavity of ß-Cyd. The interaction of ß-Cyd and azomethine was also analyzed by means of spectrometry by UV-Vis spectrophotometer to determine the formation constant. The formation constant was calculated by using a modified Benesi-Hildebrand equation at 25 °C. The apparent formation constant obtained was 1.29 × 104 L/mol. Besides that, the stoichiometry ratio was also determined to be 1:1 for the inclusion complex of ß-Cyd with azomethine.

An optimization of fungal chitin grafted polyaniline for ammonia gas detection via Box Behnken design.

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.