Spectrophotometric Determination of Trace Concentrations of Copper in Waters Using the Chromogenic Reagent 4-Amino-3-Mercapto-6-[2-(2-Thienyl)Vinyl]-1,2,4-Triazin-5(4H)-One: Synthesis, Characterization, and Analytical Applications

Concentration of potential toxic elements in canned tuna fish: systematic review and health risk assessment

The health risks (non-carcinogenic and carcinogenic risk) were calculated in both adults and children, using target hazard quotient (THQ) and carcinogenic risk (CR). The concentrations of Cd, Pb, and Ni were higher than the standard limits but they did not pose any non-carcinogenic health risks in adult and children's consumers (THQ <1). Meanwhile, the risk assessment of iAs indicates THQ > 1 for children in Egypt. Moreover, the THQ value due to Me Hg for adult in Tunisia and for children in Tunisia, Malta, Portugal, Latvia, Cambogia, Peru, South Korea, Romania, Hong Kong, United Arab Emirates, Morocco, and Egypt was higher than 1 value. In addition, the calculated CR values of iAs for the adults and children were within the threshold risk of developing cancer (Between 1.00E-4 to 1.00E-6). Therefore, it is recommended to continuously monitor the concentration of PTEs in canned tuna.

Development of two highly sensitive and selective sensor-assisted fluorescence immunoassays for trace determination of copper residues in food samples

This study describes the development of two highly sensitive and selective sensor-assisted fluorescence immunoassays for the trace determination of copper ions, Cu(ii) residues, in food samples. These assays were the microwell-based fluoroimmuoassay (FIA) and the kinetic exclusion assay (KinExA). FIA and KinExA were assisted by a microplate reader and a KinExA™ 3200 immunosensor, respectively. Both FIA and KinExA were developed utilizing the same antibody, capturing reagent, and fluorescence signal-generating reagent. The antibody was a mouse monoclonal antibody, designated as 8D66, that specifically recognized the Cu(ii)-ethylenediaminetetraacetic acid complex (Cu(ii)-EDTA) but did not recognize Cu(ii)-free EDTA. The capturing reagent was Cu(ii)-EDTA covalently linked to bovine serum albumin protein (Cu(ii)-EDTA-BSA). The fluorescence-generating reagent was an anti-mouse IgG conjugated with fluorescein isothiocyanate (IgG-FITC). Both FIA and KinExA involved competitive binding reactions between Cu(ii)-EDTA complexes, formed in the sample solution, and Cu(ii)-EDTA-BSA conjugate which has been immobilized onto microwell fluorescence assay plates (in FIA) or polymethylmethacrylate beads (in KinExA) for a limited quantity of binding sites of 8D66 antibody. The conditions of both FIA and KinExA were investigated, and the optimum procedures were established. Both FIA and KinExA were validated, and all validation parameters were acceptable. Many different metal ions that are commonly encountered in food samples did not interfere with Cu(ii) analysis by both FIA and KinExA. Both assays were applied to the determination of Cu(ii) in food samples with satisfactory accuracy and precision. Both assays were compared favorably with inductively coupled plasma atomic emission spectroscopy. Comparative evaluation of FIA and KinExA revealed that KinExA had higher sensitivity and better precision than FIA, whereas, both assays had comparable accuracy. Both FIA and KinExA were superior to the existing atomic spectrometric methods for Cu(ii). The proposed FIA and KinExA are anticipated to effectively contribute to assessing Cu(ii) concentrations and controlling the exposure of humans to its potential toxicities.

Design and optimization of sensitive analytical spectrophotometric method for micro determination of copper(II) from e-waste by using of novel chromogenic extractant

In this article, a novel spectrophotometric reagent 1-(pyrimidine)-4, 4, 6-trimethyl-1,4-dihydropyrimidine-2-thiol [PTPT] has been synthesized for liquid-liquid extraction and spectrophotometric determination of copper(II). The as-synthesized ligand has been selectively forms stable complex with copper(II) in basic medium (pH 9.0), in presence of mild pyridine the extraction and color stability has found to be synergistically enhanced. The equilibrium time is 10 min for effective extraction of copper(II) from organic phase and absorbance of colored organic complex in carbon tetrachloride is measured spectrophotometrically at λ_max 615 nm against reagent blank. The ternary complex of Cu(II)-PTPT-Py having molar ratio 1:2:2 (M:L:Py) showed green colored complex. The main factors influencing the achievement of synergistic extraction; i.e. pH, ligand concentration, type and volume of the dispersive organic solvents, equilibrium time, synergent concentration and foreign ions were investigated. The Beer's law was obeyed in the concentration range 1-20 μg mL^-1 of copper(II) and optimum concentration range is evaluated by Ringbom's plot and it is found that 2.5-25 μg mL^-1. In presence of pyridine, molar absorptivity and Sandell's sensitivity of copper(II)-PTPT complex is 2.80 × 10³ L mol^-1 cm^-1 and 0.226 μg cm^-2, respectively and in absence of pyridine, molar absorptivity and Sandell's sensitivity of copper(II)-PTPT complex is 1.35 × 10³ L mol^-1 cm^-1 and 0.469 μg cm^-2, respectively. The stoichiometry of the copper(II)-PTPT-pyridine complex was calculated by slope ratio method, mole ratio method and Job's method of continuous variation and it has been found as 1:2:2. No significant effects of potentially interfering species i.e. cations and anions were observed. The optimized method was applied for the determination of copper(II) in binary, synthetic mixtures and successfully applied for determination of copper(II) from e-waste samples. The standard deviation (R.S.D.) is 0.11% for n = 5 repetition. The reliability of the developed method is confirmed by comparison of experimental results with atomic absorption spectrophotometer.