Potentiometric sensor for iron (III) quantitative determination: experimental and computational approaches

Abstract

The current work deals with fabrication and validation of a new highly Fe3+ selective sensor based on benzo-18-crown-6 (b-18C6) using the potentiometric method. The proposed sensor revealed satisfactory performance for quantitative evaluation of Fe3+ trace amount in environmental samples. The ratio of membrane ingredients optimized and the membrane with the composition of 4:30:65.5:0.5 mg of b-18C6:PVC:o-NPOE:KTpClPB exhibited the desirable Nernstian slope of 19.51 ± 0.10 (mV per decade of activity) over the pH range from 2.5 to 5.7 with an acceptable dynamic concentration range of 1.0 × 10−6 M to 1.0 × 10−1 M and lower detection limit of 8.0 × 10−7 M. The proposed sensor demonstrated an appropriate reproducibility with a rapid response time of 12 s and the suitable lifetime of 10 weeks. To validate the accurate response of the proposed sensor, AAS technique applied for the determination of Fe3+ in real aqueous mediums such as drinking tap water and hospital wastewater sample after treatment by electrocoagulation process. Theoretical studies carried out using DFT/B3LYP computational level with 6-311G basis set to optimize the adsorption sites of Fe+3 cationic species by b-18C6. The obtained adsorption energy with large negative value confirmed the formation of a stable complex.

RETRACTED ARTICLE: Citrate stabilized Fe3O4/DMG modified carbon paste electrode for determination of octamethylcyclotetrasiloxane in blood plasma and urine samples of cement factory workers

“…The magnetic characteristic of Cit-Fe 3 O 4 nanocrystals was evaluated by a vibrating-sample magnetometer (VSM). The nanocrystals exhibit superparamagnetic behavior and have lower saturation magnetization value than the bulk magnetization (~ 92 emu/g) [22]. Magnetization hysteresis loop of Cit-Fe 3 O 4 is shown in Fig.…”

Characterization of PVA-Enzyme Coated Indicator Electrodes GA coated again with PVC-KTpClPB-o-NPOE UV-Vis analysis, variable signal analysis, sensor sensitivity and SEM-EDS

“…B1-4 is an indicator electrode coated with PVA-E 1x coated with GA 2.9 % 1x coated again with PVC-KTpClPB 1x entrapment method. Membranes containing o-NPOE as a plasticizer with a higher dielectric constant (ɛ = 24) showed the best Nernstian response (Badakhshan, 2019). Membranes containing DOP provide lower detection limits and a wider linearity range than those containing the o-NPOE plasticizer (Elbehery, 2019).…”

“…The PVC within the permissible limits provided the membrane electrode having the composition of PVC: o-NPOE: DPA: NaTPB as 33:61:3:3 (w/w) as the optimum composition with the closest Nernstian response (Kaur, Chhibber and Mittal, 2017). Composition 30:65.5:0.5 mg PVC: o-NPOE: KTpClPB (Badakhshan, 2019), about the composition of PVC, plasticizers and lipophilic additives. Ionophores (I) 1.10% (w/w), lipophilic salt (KTpClPB) 0.25% (w/w), plasticizer (o-NPOE) 65.65% (w/w), and PVC 33.00 % (w/w) dissolved in tetrahydrofuran (Lenar, 2020).…”

Characterization of PVA-Enzyme Coated Indicator Electrodes GA coated again with PVC-KTpClPB-o-NPOE SEM-EDS, FTIR and XRD analysis

“…The permissible limit of PVC on the membrane electrode has the composition of PVC: o-NPOE: DPA: NaTPB as 33:61:3:3 (w/w) as the optimum composition with the closest Nernstian response (Kaur, Chhibber and Mittal, 2017). The composition according to (Badakhshan, 2019) is 30:65.5:0.5 mg of PVC: o-NPOE: KTpClPB, as a composition of PVC, plasticizer and lipophilic additive. Ionophores (I) 1.10% (w/w), lipophilic salt (KTpClPB) 0.25% (w/w), plasticizer (o-NPOE) 65.65% (w/w), and PVC 33.00 % (w/w) dissolved in tetrahydrofuran (Lenar, 2020;Hasan, 2019); 0.05 wt% KTpClPB as membrane additive, and 1 wt% ionophore, 33 wt% PVC and 66 wt% plasticizer (o-NPOE) (Rizk, et al, 2009); 62.5 mg PVC, 130 mg o-NPOE, 1% by weight s prepared containing 62.5 mg PVC, 130 mg o-NPOE, 1% by weight ionophore and 80 to 140 mol% KTpClPB (relative to the ionophore).…”