Chemical Suppression of Contaminant Metal Ions Using a Metastable State in Precolumn Derivatizing HPLC:  An Ultratrace Fluorometric Detection of Al(III)

Abstract

The contamination of metal ions from reagents used frequently restricts the practical detection limit of the metal ion, which itself is a source of contamination. We have found a novel solution to this problem, a chemical-suppressing method of contaminant metal ions on a reversed-phase HPLC for Al3+ with a detection limit of 7.6 x 10(-11) mol dm(-3) (2.1 ng dm(-3)) by only adding a certain agent into all stock solutions without any preconcentration or purification steps. This technique decreases the concentration of the contaminant Al3+ originating from the reagents by more than 1 order of magnitude using selective derivatization of sample Al3+ ions to a powerful fluorescent complex at a metastable state in the precolumn chelation processes. Meanwhile, the contaminant Al3+ remains as a nonfluorescent complex with a blocking reagent in order to suppress the contamination. This selective derivatization is achieved by the accumulation of several complexation processes based on the difference of formation, dissociation, and ligand-exchange kinetics and the thermodynamics between the derivatizing reagent, the 4',5'-geometorical isomer of calcein, and the blocking reagent, o,o'-dihydroxyazobenzene. This simple and smart HPLC system was validated through recovery tests of environmental and biological samples.

Direct fluorometric detection of paramagnetic and heavy metal ions at sub‐amol level using an aromatic polyaminocarboxylate by CZE: Combination of pre‐ and on‐capillary complexation technique

“…Another way is to apply preconcentration techniques. Although more sensitive methods will be adversely affected by contaminant metal ions precisely due to their high sensitivity, the chemical suppression of contaminants for precolumn derivatization method, which has been reported in our previous paper [29], could be applied. To avoid the disturbance of electropherogram by Ca 21 , the synthesis and investigation of electrophoretic behavior in CE of some novel polyaminocarboxylate ligands, such as DOTA and DTPA with a fluorescein structure, is now underway.…”

“…(ii) Distance between the metal-binding moiety and the fluorophore is desirable in order to prevent the fluorophore from quenching due to the paramagnetic or heavy atom effect. In our previous works, the calcein complexes with paramagnetic metal ions, in which the metal is in vicinity of the fluorophore, strongly quench the ligand-centered emission through deactivation of the excited state by the nonradiative quenching process [29]. Furthermore, in another work on metal complexes with ABEDTA, in which the antenna moiety is attached to the backside of the metalbinding sites, the distance between the fluorophore and the center metal was about 5-6 Å.…”

Ratiometric Fluorescent Sensor for Al3+ Based on the Inner Filter and Static Quenching Effects of Carbon Dots Obtained from Neem Leaves

“…To date, a diversity of analytical methods for the detection of Al 3 + have been established with specific techniques, such as atomic absorption spectrometry (AAS), [6] inductively coupled plasma-atomic emission spectrometry (ICP-AES), [7] inductively coupled plasma-mass spectroscopy (ICP-MS), [8] laser ablation microprobe mass analysis (LAMMA), [9] high performance liquid chromatography (HPLC). [10] However, most of these methods involve expensive instrumentations and complicated operations, which will increase the detection costs and environmental risks. To address the above problems, fluorimetry has been paid more attention for the development of sensors owing to its high sensitivity and selective response capability.…”

Cobalt metal-mixed organic complex-based hybrid micromaterials: ratiometric detection of cyanide

“…A mixed ligand of 2-hydroxyazobenzene derivatives, 19 DHAB and TAC, was chosen in this work for the following reasons. (a) The mixed ligand provides synergistic coordination with metal ions, considering the deprotonation process (pK a ) of hydroxyl groups 20,21 to make the metal-oxygen bonds. Such process is a critical factor in the formation of metal-organic complexes.…”