SPME fiber coated by arrayed ZNRs for sampling and concentration of polar residual solvents for further analysis using GC FID.

In this work, fused silica coated by arrayed ZNRs were successfully applied as a sorbent for analysis of polar residual solvents in pantoprazole feedstocks. ZnO nanoparticles were produced and deposited on a fused silica surface applying the dip coating technique and hydrothermal growth to synthesize the arrayed nanorods. The ZNRs array fiber coating was characterized by SEM, EDS, XRD, and TGA. The manufactured SPME fiber was coupled to a glass syringe of 10 µL and applied for the sampling of acetone, n-butanol, dichloromethane, ethyl acetate and methanol for further analysis using GC FID. Optimum operating conditions were determined for the incubation temperature (70 °C), incubation time (15 min), extraction time (120 s), and desorption time (0.6 min). Employing the optimum conditions, the proposed method resulted in a good linearity (> 0.997) and precision (< 7.1%) for the evaluated analytes. Recovery tests were also performed on three levels (below, equal to and above the ICH specification limit for residual solvents in pharmaceutical products). Recoveries ranging from 96% to 107% were obtained. Comparison between the reference method and developed method shows errors smaller than 4%.

ZnO-coated glass fibers for the analysis of trihalomethanes by headspace-solid phase microextraction-gas chromatography.

Li(2)O-ZrO(2)-BaO-SiO(2) glass fibers were produced and their surfaces were coated with zinc oxide. The fibers' surface morphology was examined by scanning electron microscopy and the zinc oxide layer was characterized by mapping the K(α) and L(α) lines of zinc by energy dispersive X-ray spectroscopy. The results indicated that a homogeneous and porous layer of ZnO was formed on the fibers' surface. This layer was subjected to a simultaneous determination of trihalomethanes using headspace-solid phase microextraction-gas chromatography. The study was conducted after evaluating the ideal time of incubation (15 min), extraction (15 min) and desorption (10 min), as well as the effect of the addition of salt (15%, m/v) on the analytical response. A good linear dynamic range was observed individually for trihalomethanes aqueous solutions containing 20 µg L(-1) and 500 µg L(-1) of trichloromethane, 15 µg L(-1) and 250 µg L(-1) of dichlorobromomethane and dibromochloromethane and 10 µg L(-1) and 100 µg L(-1) of tribromomethane, with all the compounds showing correlation coefficients higher than 0.9900.