A novel sensor for the selective monitoring of trace ytterbium ions using an agarose-based optical membrane

A novel highly selective sensitive optical sensor was prepared via the chemical immobilization of β-2-hydroxybenzyl-5-bromo-2-hydroxyazastyrene (HBBHAS) on an epoxy-activated agarose membrane pieces. The absorbance variation of the immobilized azastyrene film on agarose upon the addition of 1.5 × 10(−5) M aqueous solutions of La(3+), Y(3+), Al(3+), Sc(3+), Sm(3+), Eu(3+), Lu(3+), Fe(3+), Ce(3+), Cr(3+), S(2)O(3)(2−), Tb(3+), Mn(2+) and KIO(3) revealed substantially higher changes for the Yb(3+) ion compared to the other considered ions. Thus, using HBBHAS as an appropriate ionophore, a selective optical sensor for Yb(3+) was prepared via its chemical immobilization on a transparent agarose membrane. The effects of pH, reagent concentration, and time duration of the reaction of immobilizing the reagent were examined. A distinct change in the maximum absorbance of the reagent was established on contact of the sensing membrane with Yb(3+) ions at pH = 4.25. For the membrane sensor, a linear relationship was observed between the variation in membrane absorbance (ΔA) at 424 nm and Yb(3+) concentrations in the range of 4.75 × 10(−5) to 6.20 × 10(−10) M with a detection limit of 1.9 × 10(−10) M for Yb(3+). The effects of some potentially interfering ions on the assessment of Yb(3+) were analyzed, and no substantial interference was found. The sensor showed a short response time and decent durability with no reagent leaching. The recovery of Yb(3+) ions from the sensor material was performed using 0.3 M HNO(3) and its response was reversible and reproducible with RSD ≥ 1.95%. This study reports a non-toxic, economical, stable, accurate, easy-to-use, and novel optical sensor material to assess Yb(3+) in synthetic and environmental water samples.