Exploring the design and performance of a tellurium optical sensor utilizing a plasticizer-free polymer inclusion membrane.

A highly responsive, discerning, and uncomplicated technique has been devised for immobilizing reagents onto a plasticizer-free optical sensor membrane, employing polymer inclusion membranes (PIMs). This procedural strategy relies on a physical immobilization approach, specifically encapsulation, resulting in the creation of an optical sensing membrane. The responsive PIM is composed of poly(vinyl chloride) (PVC) as the fundamental polymer, Aliquat 336 as an extractant, and 4-(4 -chlorobenzylideneimino)-3-methyl-5-mercapto-1,2,4-triazole (CBIMMT) as the reagent. The optimized sensor demonstrates a linear range of 6.00-156 ng/mL for Te(IV), along with detection and quantification limits of 1.75 and 5.60 ng/mL, respectively. The sensor response time is 3.0 min, confirming its reproducibility. Effective regeneration of the sensor is achieved using a 0.2 mol/L HCl solution. The sensor membrane's selectivity is evaluated against various interfering ions, underscoring minimal interference. The sensor membrane efficacy is demonstrated through successful applications in quantifying Te(IV) levels, including natural water, chalcogenides, milk, vegetables, and soil samples.

Potentially toxic metals in irrigation water, soil, and vegetables and their health risks using Monte Carlo models.

Food safety has become a serious global concern because of the accumulation of potentially toxic metals (PTMs) in crops cultivated on contaminated agricultural soils. Amongst these toxic elements, arsenic (As), cadmium (Cd), chromium (Cr), and lead (Pb) receive worldwide attention because of their ability to cause deleterious health effects. Thus, an assessment of these toxic metals in the soils, irrigation waters, and the most widely consumed vegetables in Nigeria; Spinach (Amaranthushybridus), and Cabbage (Brassica oleracea) was evaluated using inductively coupled plasma-optical emission spectroscopy (ICP-OES). The mean concentration (measured in mg kg-1) of the PTMs in the soils was in the sequence Cr (81.77) > Pb(19.91) > As(13.23) > Cd(3.25), exceeding the WHO recommended values in all cases. This contamination was corroborated by the pollution evaluation indices. The concentrations (measured in mg l-1) of the PTMs in the irrigation water followed a similar pattern i.e. Cr(1.87) > Pb(1.65) > As(0.85) > Cd(0.20). All the PTMs being studied, were found in the vegetables with Cr (5.37 and 5.88) having the highest concentration, followed by Pb (3.57 and 4.33), and As (1.09 and 1.67), while Cd (0.48 and 1.04) had the lowest concentration (all measured in mg kg-1) for cabbage and spinach, respectively. The concentration of the toxic metals was higher in spinach than in cabbage, which may be due to the redistribution of the greater proportion of the metals above the ground tissue, caused by the bioavailability of metals in the aqueous phase. Expectedly, the hazard index (HI),and carcinogenic risk values of spinach were higher than that of cabbage. This implies that spinach poses potentially higher health risks. Similarly, the Monte Carlo simulation results reveal that the 5th percentile, 95th percentile, and 50th percentile of the cumulative probability of cancer risks due to the consumption of these vegetables exceeds the acceptable range of 1.00E-6 and 1.00E-4. Thus, the probable risk of a cancerous effect is high, and necessary remedial actions are recommended.

A modified selective optical sensor for selenium determination based on incorporating xylenol orange in a poly(vinyl chloride) membrane.

A novel optical sensor has been developed to measure selenium ions. The sensor membrane was created by mixing xylenol orange (XO) and sodium tetraphenylborate (NaTPB) with a plasticized poly(vinyl chloride) membrane that contained o-nitrophenyl octyl ether (o-NPOE) as a plasticizer. XO was previously established for use in a colorimeter to measure selenium in water and other media. At pH 6.6, the color of the detecting membrane changed from orange to pink when in contact with Se4+ ions. Various variables affecting the uptake efficiency were evaluated and optimized. Under optimum conditions (i.e., 30% PVC, 60% o-NPOE, and 5.0% of both XO and NaTPB for 5.0 min as the response time), the proposed sensor displayed a linear range 10-175 ng mL-1 with the detection and quantification limits of 3.0 and 10 ng mL-1, respectively. Also, the precision (RSD%) was better than 2.2% for six replicate determinations of 100 ng mL-1 Se4+ in various membranes. For the detection of Se4+, the selectivity of the sensor membrane was investigated for a number of possible interfering inorganic cations, but no appreciable interference was found. With the use of a 0.3 M HCl solution, the sensor was successfully restored, and the response that may have been reversible and reproducible exhibited an RSD% of less than 2.0%. The sensor has been successfully used to analyze Se4+ ions in environmental and biological materials.

Construction of an optical sensor for copper determination in environmental, food, and biological samples based on the covalently immobilized 2-(2-benzothiazolylazo)-3-hydroxyphenol in agarose.

An optical chemical sensor has been developed for the quantitative spectrophotometric analysis of copper. The optode is dependent on covalent immobilization of 2-(2-benzothiazolylazo)-3-hydroxyphenol (BTAHP) in a transparent agarose membrane. The absorbance variation of immobilized BTAHP on agarose as a film upon the addition of 5 × 10-3 M aqueous solutions of Mn2+, Zn2+, Hg2+, Cd2+, Pb2+, Co2+, Ni2+, Fe2+, La3+, Fe3+, Cr3+, Zr4+, Se4+, Th4+, and UO22+ revealed substantially higher changes in the Cu2+ ion content compared to other ions investigated here. The effects of various experimental parameters, such as the solution pH, the reaction time, and the concentration of reagents, on the quality of Cu2+ sensing were examined. Under ideal experimental circumstances, a linear response was achieved for Cu2+ concentrations ranging from 1.0 × 10-9 to 7.5 × 10-6 M with an R2 value of 0.9988. The detection (3σ) and quantification (10σ) limits of the procedure for Cu2+ analyses were 3.0 × 10-10 and 9.8 × 10-10 M, respectively. No observable interference was recorded in the detection of Cu2+ due to other inorganic cations. With no indication of BTAHP leaching, the membrane demonstrated good durability and quick response times. The optode was effectively used to determine the presence of Cu2+ in environmental water, food, and biological samples.

Ultrasensitive and highly selective detection of nickel ion by two novel optical sensors.

Novel optical sensors for nickel determination by incorporation of 5-(2`-bromo-phenylazo)-6-hydroxypyrimidine-2,4-dione (I), 5-(2`,4`-dimethylphenylazo)-6-hydroxypyrimidine-2,4-dione (II), dibutylphthalate (DBP) and sodium tetra-phenylborate (Na-TPB) to the plasticized polyvinyl chloride matrices were prepared. The introduction of DBP in the membrane substantially increased the ability of both ionophores I and II to function as chromo ionophores. The advantages of the reported sensors include great stability, reproducibility, and relatively long lifespan, as well as excellent selectivity for Ni2+ ion detection across a wide range of alkali, alkaline earth, transition, and heavy metal ions.Under optimized membrane compositions and experimental parameters, the response of both sensors was linear throughout a concentration range of 3.5 × 10-8 to 8.1 × 10-5 and 2.0 × 10-8 to 5.1 × 10-5 M for I and II, respectively. Sensor detection and quantification limits based on the definition that the concentration of the sample leads to a signal equal to the blank signal plus three and ten times its standard deviation were determined to be 1.15 × 10-8 and 3.45 × 10-8 M when utilizing I, whereas they were 0.61 × 10-8 and 1.95 × 10-8 M when utilizing II, respectively. The reaction time of optodes is defined as the period required achieving 95% of based sensors and found to be 8.0 and 5.0 min using I and II, respectively. Ni2+ ion concentrations in water, food, and environmental samples were effectively determined using the proposed optical sensors. Representative diagram for preparation of the sensing Ni2+ sensor.

New Natural Eugenol Derivatives as Antiproliferative Agents: Synthesis, Biological Evaluation, and Computational Studies.

Semisynthetic modifications of natural products have bestowed us with many anticancer drugs. In the present work, a natural product, eugenol, has been modified synthetically to generate new anticancer agents. The final compounds were structurally confirmed by NMR, IR, and mass techniques. From the cytotoxicity results, compound 17 bearing morpholine was found to be the most active cytotoxic agent with IC50 1.71 (MCF-7), 1.84 (SKOV3), and 1.1 µM (PC-3) and a thymidylate synthase (TS) inhibitor with an IC50 of 0.81 µM. Further cellular studies showed that compound 17 could induce apoptosis and arrest the cell cycle at the S phase in PC-3 carcinoma. The docking study strongly favors compound 17 to be a TS inhibitor as it displayed a similar interaction to 5-fluorouracil. The in silico pharmacokinetics and DFT computational studies support the results obtained from docking and biological evaluation and displayed favorable pharmacokinetic profile for a drug to be orally available. Compound 17 was found to be a promising TS inhibitor which could suppress DNA synthesis and consequently DNA damage in prostate cancer cells.