Design a sensitive optical thin film sensor based on incorporation of isonicotinohydrazide derivative in sol-gel matrix for determination of trace amounts of copper (II) in fruit juice: Effect of sonication time on immobilization approach

Simple colorimetric copper(II) sensor - Spectral characterization and possible applications

New o-hydroxyazocompound L bearing pyrrole residue was obtained in the simple synthetic protocol. The structure of L was confirmed and analyzed by X-ray diffraction. It was found that new chemosensor can be successfully used as copper(II) selective spectrophotometric regent in solution and can be also applied for the preparation of sensing materials generating selective color signal upon interaction with copper(II). Selective colorimetric response towards copper(II) is manifested by a distinct color change from yellow to pink. Proposed systems were effectively used for copper(II) determination at concentration level 10^-8 M in model and real samples of water.

A Sol-gel Membrane Utilized Cellulose Paper Doped with α-furil Dioxime for Colorimetric Determination of Nickel

A simple and sensitive colorimetric sensor for nickel(II) ions has been successfully prepared by immobilizing α-furil dioxime reagent in the sol-gel matrix with a solid supporting filter paper medium. The sensor was developed using tetraethyl orthosilicate (TEOS) precursors with 4 days aging time, the mole ratio of water: precursor was 4:1, and reagent concentration at 0.10%. The sensor was quantified by utilizing the Red (R), Green (G), and Blue (B) values ​​of the colors that were successfully displayed after the detection process. The RGB value is confirmed by the Euclidean Distance (ED) equation to determine the optimum conditions. There was no observed degree of leaching in plain sight, and the result of leaching investigation by the double dyeing method did not show any significant change. The linear range was ​​0.10 to 2.8 ppm with an R² of 0.9964. The values of LOD and LOQ were 0.1 ppm and 0.4 ppm, respectively. In addition, the sensor was free from interfering species and had a percent recovery around 90 to 110%.

Optical Chemical Sensor Based on 2,2-Furildioxime in Sol-Gel Matrix for Determination of Ni2+ in Water

A new optical chemical sensor was fabricated based on incorporation of 2,2-furildioxime as a sensitive reagent into the nanopore of a transparent glasslike material through the sol-gel method which was suitable for determination of Ni2+ ions in aqueous solutions. The prepared sensors were composed of tetraethoxysilane (TEOS), 2,2-furildioxime, methanol, hydrochloric acid and Triton X-100. The sensors were constructed by dip coating onto glass substrates. The optimum response of the sensor toward Ni2+ ions was reached at pH 8.5 and the contact time for the formation of the complex at 10 min. The linear concentration of the calibration curve was in the range of 1–5 mg L−1 with a detection limit of 0.111 mg L−1, and quantification limit of 0.337 mg L−1. In addition, the relative standard deviation (RSD) was less than 5% in determination of Ni2+ with ten slide sensor membranes. The developed sensor was tested on Ni2+ determination in real water samples which was confirmed by the atomic absorption spectrophotometer method.