Polyaniline-silica doped with oxalic acid as a novel extractor phase in thin film solid-phase microextraction for determination of hormones in urine.

In this study, different polyanilines were synthesized and evaluated for the determination of three hormones, including 17-β-estradiol, 17-α-ethinylestradiol, and estrone, in urine using a novel methodology based on thin film solid-phase microextraction technique, employing the sampling well plate system. The extractor phases, designated as polyaniline doped with hydrochloric acid, polyaniline doped with oxalic acid, polyaniline-silica doped with hydrochloric acid, and polyaniline-silica doped with oxalic acid, were characterized by electrical conductivity measurements, scanning electron microscopy, and Fourier transform infrared spectroscopy. The optimized extraction conditions were composed of 1.

Composite resin reinforced with pre-tensioned glass fibers. Influence of prestressing on flexural properties.

Objectives: This investigation evaluated the flexural properties of two composite resins, and the influence of unidirectional glass fiber reinforcements, with and without pre-tensioning.

Methods: Two composite resins (Q: Quixfil and A: Adoro) were used to fabricate 2 mm x 2 mm x 25 mm beams (N = 10), reinforced with two fiber bundles along the long axis of the beam and pre-tensioned under a load equivalent to 73.5% of its tensile strength (groups QPF and APF).