Leila Narimani

Titanium (III) cation selective electrode based on synthesized tris(2pyridyl) methylamine ionophore and its application in water samples

The introduction of low detection limit ion selective electrodes (ISEs) may well pave the way for the determination of trace targets of cationic compounds. This research focuses on the detection of titanium (III) cation using a new PVC-membrane sensor based on synthesized tris(2pyridyl) methylamine (tpm) ionophore. The application and validation of the proposed sensor was done using potentiometric titration, inductively coupled plasma atomic emission spectrometry (ICP-AES), and atomic absorption spectrometry (AAS). The membrane sensor exhibited a Nernstian response to the titanium (III) cation over a concentration range of 1.0 × 10−6–1.0 × 10−2 M and pH range from 1–2.5. The Nernstian slope, the lower of detection (LOD), and the response time (t95%) of the proposed sensor were 29.17 ± 0.24 mV/dec, 7.9 × 10−7 M, and 20 s, respectively. The direct determination of 4–39 μg/ml of titanium (III) standard solution showed an average recovery of 94.60 and a mean relative standard deviation of 1.8 at 100.0 μg/ml. Finally, the utilization of the electrodes as end-point indicators for potentiometric titration with EDTA solutions for titanium (III) sensor was successfully carried out.

Tunable S-Band Q-Switched Fiber Laser Using Bi 2 Se 3 as the Saturable Absorber

This paper describes a successful demonstration of S-band region wavelength output generated via a tunable Q-switch fiber laser with the topological insulator (TI) Bi2Se3 as a saturable absorber (SA). The modulation depth of the TI was measured as 11.1%, whereas the utilized 980-nm laser source operated at 100 mW pump power. By inserting the TI-SA between two ferrules and utilizing a tunable bandpass filter (TBPF), a stable and tunable Q-switching operation was achieved over the S-band wavelength region from 1493.6 to 1508.9 nm, wherein pulsewidth was 7.6 μs, and the tunable repetition rate ranged from 26.1 to 36.6 kHz. The Q-switched pulses had maximum pulse energy of 6.1 nJ, as measured from 2.5% of the cavity output. The results provide evidence that a TI-based SA is suitable for pulsed laser operation in the S-band wavelength region and offers potential for further development as an ultrabroadband photonics device.

A novel potentiometric self-plasticizing polypyrrole sensor based on a bidentate bis-NHC ligand for determination of Hg(II) cation

In this approach, a new potentiometric self-plasticizing polypyrrole sensor was constructed based on a bidentate bis-NHC ligand for the purpose of Hg2+ cation determination. An ionophore, namely bis[1-benzyl-benzimidazoliumethyl]-4-methylbenzenesulfonamide bromide (NHCL) was successfully synthesized and characterized using FT-IR, 1H NMR, 13C NMR spectroscopy, CHN elemental analysis, X-ray single crystal diffraction and UV-Vis spectroscopy. The electrode with a membrane optimum composition demonstrated a good Nernstian response to Hg2+ cations ranging from 1.0 × 10−6 to 1.0 × 10−2 M with a detection limit of 2.5 × 10−7 M and a Nernstian slope of 28.10 ± 0.29 mV per decade over a pH range between 4.5–7.0 with a response time of about 20 seconds at room temperature. The electrode exhibited better selectivity towards Hg2+ ions in comparison with some soft and hard metals; most of these metal ions do not show significant interference . The proposed electrode also has applications in the direct determination of Hg2+ cations in aqueous solutions with sensible accuracy and precision.

Ethyl­enediaminium hemioxalate thio­cyanate

In the title compound, C2H10N2 2+·0.5(C2O4)2−·NCS−, the ethylenediaminium dication adopts a (+)-synclinal conformation with an N—C—C—N torsion angle of 62.64 (15)°. The oxalate dianion lies across an inversion centre. In the crystal structure, the ions are linked through N—H⋯N, N—H⋯O and C—H⋯S hydrogen bonds, leading to the formation of a three-dimensional network.

An overview of detection techniques for monitoring dioxin-like compounds: latest technique trends and their applications

Dioxin-like compounds (DLCs) are considered persistent bioaccumulative toxicants with a number of continuing issues in the fields of ecotoxicology and bioassay. In spite of the great need to monitor these compounds, the only analytical technique with sufficient sensitivity and selectivity for determination of DLCs is a combination of high-resolution gas chromatography and high-resolution mass spectrometry. However, these methods require aseptic techniques, long incubation times, and sophisticated technical expertise for getting accurate results. Nowadays, biological techniques such as biomarkers, bioassays, enzyme immunoassays (EIAs), or other methods have been greatly developed as more sensitive, cost-effective and rapid techniques to determine the presence of DLCs in trace levels of environmental and biological samples. The main aim of this study is to review the latest analytical and bioanalytical detection methods (BDMs) for diagnosis and monitoring of DLCs. Likewise, this work characterizes the latest techniques and trends based on their application, advantages and shortcomings for the various BDMs and their differences are also noted.

2,4-Diamino-6-methyl-1,3,5-triazin-1-ium hydrogen oxalate

The title compound, C4H8N5 +·C2HO4 −, was obtained from the reaction of oxalic acid and 2,4-diamino-6-methyl-1,3,5-triazine. The protonated triazine ring is essentially planar with a maximum deviation of 0.035 (1) Å, but the hydrogen oxalate anion is less planar, with a maximum deviation of 0.131 (1) Å for both carbonyl O atoms. In the crystal, the ions are linked by intermolecular N—H⋯O, N—H⋯N, O—H⋯O and C—H⋯O hydrogen bonds, forming a three-dimensional network. Weak π–π [centroid–centroid distance = 3.763 Å] and C—O⋯π interactions [O⋯centroid = 3.5300 (16) Å, C—O⋯centroid = 132.19 (10)°] are also present.