Quantitative determination of Al(iii) ion by using Alizarin Red S including its microspheres optical sensing material

Abstract

A facile UV-Vis spectrophotometric method for quantitative determination of Al 3+ ion based on chromophoric Alizarin Red S (ARS) was carried out. ARS reagent was used as an organic chelator for Al 3+ ion to form ARS-Al(III) complex. The yellow-coloured ARS changed to reddish-orange hue after reaction with Al 3+ ion and formed ARS-Al(III) complex at optimum pH 4. ARS reagent yielded linear concentration range over 0.1-1.0 ppm Al 3+ ion and a fast response time of $35 s. The reproducibility study for ARS-Al(III) complex was found to give satisfactory relative standard deviation (RSD) values of 2.4-3.1%. The ARS reagent demonstrated good photostability over an 8-hour experimental period. An attempt has been conducted to physically immobilize ARS reagent onto newly synthesized photocurable poly(n-butyl acrylate) [poly(nBA)] microspheres, followed by reflectometric transduction of ion recognition event. The micro-sized poly(nBA) spheres has been confirmed by scanning electron microscopy (SEM). The colour change of the immobilized ARS, i.e. before and after reaction with Al 3+ ion was found to be similar to the ARS solution analysis at pH 4. The acrylic-based optical microsensor showed potential to accommodate both quantitative and semiquantitative in situ evaluation of Al 3+ ion concentration in environmental water and biological fluids.

Colorimetric Assay for Al3+ Based on Alizarin Red S-functionalized Silver Nanoparticles

“…This result further confirms that the aggregating process of ARS-AgNPs is dependent on the covalent bonding between the hydroxyl (-OH) and the carbonyl (C¼O) groups of ARS on the surface of AgNPs with Al 3þ . [18,19] The interaction between ARS and metal ions was investigated as well, and the spectra of ARS in the presence of various cations is presented in Fig. S3.…”

“…The free electrons from the chromophoric ARS are transferred to the d orbital of the Al 3þ ion, where covalent bonds to the ligand are formed, resulting in the aggregation of ARS-Ag NPs. [19] The reaction time between ARS-AgNPs and Al 3þ is a key point that affects the colorimetric assays. The relationship between reaction time and absorption ratio (A 600nm /A 395nm ), shown in Fig.…”

“…In detail, ARS was immobilized on the poly(n-butyl acrylate) microspheres via physical adsorption for optical sensing of the Al 3þ ion. The work showed that the ARS reagent yielded a linear response over a concentration range of 0.1-1.0 ppm Al 3þ and a fast response time of ,35 s. Supian et al [19] discussed interference from foreign ions, and revealed that this system as reported did not have much selectivity. In Supian's work, only three metal ions (Mg 2þ , Fe 3þ , and Cu 2þ ) were selected for the interference study.…”

“…ARS is one of the most useful photometric reagents to determine metal ions owing to its ability to create chelates with a multitude of metal cations. [18] Supian et al [19] reported a quantitative determination of Al 3þ by using ARS in its microspheres optical sensing material. In detail, ARS was immobilized on the poly(n-butyl acrylate) microspheres via physical adsorption for optical sensing of the Al 3þ ion.…”

Fluorescent carbon dots for sensitive determination and intracellular imaging of zinc(II) ion

“…5a, Al 3+ caused the change of fluorescence enhancement. However, Al 3+ is a nonessential element for living systems, human body naturally contains only 35 mg Al 3+ (about 0.7 ppm; while Zn 2+ about 60 ppm) [33,34]. It suggested that, in common bio-system, Al 3+ cannot cause obvious effect on the detection of Zn 2+ .…”