Sustainable non-plasticized polymer inclusion membrane containing an immobilizing optode ligand for in situ ultra-sensitive colorimetric measurement and pre-concentration of beryllium ions in environmental and biological matrices

Abstract

Beryllium (Be2+) is a type of alkaline earth-divalent metal that enters many strategic industries. The work environment limits concentrations of beryllium is in the range of 0.01 – 1.0 μg mL−1 (ppm), where concentrations exceeding 5.0 ppm of Be2+ lead to acute toxicity, causing pulmonary edema and chemical pneumonitis. Herein, Be2+ was measured selectively in situ down to ultralow concentration levels utilizing a fabricated sensitive polymer inclusion membrane (PIM) as an immobilizing non-plasticized colorimetric optical sensor (optode). The PIM-sensitive optode has been created using an encapsulation method with polyvinyl chloride (PVC) as a polymer base, an (E)-6-(4-((2,5-dihydroxyphenyl)diazenyl)phenyl)-2-oxo-4-phenyl-1,2-dihydropyridine-3-carbonitrile (DDP-OPDC) as a selective ligand, and Aliquat 336 as an enhancer extractant. The linear dynamic range of the various standard measurements ranged between 5.0 and 145 ng mL−1 with excellent sensitivity down to 1.6 ng mL−1. Moreover, the manufactured optode was reusable and had sustainable mechanical strength. The method has also successfully quantified Be2+ in the livers and muscles of bovine, chicken, and pork (recovery %; 98.0–––102.3 %) in addition to Be2+ analysis in contaminated tap, mineral, and well water (recovery %; in the range of 93.6–––103.3 %). With an assessment duration of 10 min at a maximum absorbance of 622 nm, the colorimetric evaluations of Be2+ in various samples (water and biological) were rapid, reliable, and reproducible. Furthermore, the obtained results by the developed optode matched excellently those obtained by the comparison atomic absorption spectrometry method.