Optimization and evaluation of ultra-trace amounts of lead in real samples using sol–gel based optical sensor coupled with colorimetry
Autor: | Mai Aish, Reem F. Alshehri, Alaa S. Amin, Hesham H. El-Feky |
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Jazyk: | angličtina |
Rok vydání: | 2023 |
Předmět: | |
Zdroj: | Talanta Open, Vol 8, Iss , Pp 100253- (2023) |
Druh dokumentu: | article |
ISSN: | 2666-8319 |
DOI: | 10.1016/j.talo.2023.100253 |
Popis: | The entrapment of the sensitive reagent 5-(2′-bromophenylazo)-6‑hydroxy-pyrimidine-2,4‑dione (BPAHPD) in a silica sol-gel thin film coated on a glass substrate has been investigated for the development of a highly sensitive and selective optode for the determination of lead ions. The fabrication of thin films requires tetraethoxysilane as a precursor, a sol-gel pH of 2.75, a water: alkoxide ratio of 5:1, and a BPAHPD concentration of 4.0 × 10–4 M. The effect of sol-gel parameters on the optode's sensing performance was investigated. The fabricated optode is utilized for lead ion detection over a dynamic range of 4.00–144 ng mL–1 with detection and quantification limits of 1.20 and 3.95 ng mL–1, respectively. It gave repeatable results with relative standard deviation (RSD) values of 1.90% and 1.15% for lead concentrations of 40.0 and 80.0 ng mL–1, respectively, and a response time of two minutes. Through capturing BPAHPD in a sol-gel matrix and appropriately modifying the structure of doped sol-gel, interference studies have determined that lead exhibits a high degree of selectivity. To ascertain total lead, Pb4+ was reduced to Pb2+ using a few drops of 6.00 M hydrochloric acid and a freshly prepared sodium azide solution of 2.50 % (w/v). The optode can be easily regenerated with 0.15 M of nitric acid solution. The optode has complete reversibility. Optode detection of lead in diverse vegetable, food, biological, water, and soil samples yielded favorable results when compared to other techniques. |
Databáze: | Directory of Open Access Journals |
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