CE with on‐line detection by ICP‐MS for studying the competitive binding of zinc against cadmium for glutathione

Abstract

Development of a feasible method for studying the competitive interaction between a pair of antagonists is essential for understanding the antagonism of trace metals in biological systems. Herein, we report the application of CE on-line coupled with ICP mass spectroscopy (CE-ICP-MS) to investigate the competitive binding of Zn(2+) against Cd(2+) for glutathione (GSH), which is related to the detoxification of Cd(2+) in biological system, and introduce a method to evaluate the kinetics and thermodynamics for the competitive binding of Zn(2+) against Cd(2+) for GSH. The CE-ICP-MS hybrid technique allows easy and sensitive probing of the competitive binding of Zn(2+) against Cd(2+) for GSH and quantitative determination of the important thermodynamic and kinetic parameters of the competitive binding of Zn(2+) against Cd(2+) for GSH. Owing to the high sensitivity and element selectivity with multi-elements detection capacity of ICP-MS, we detailed the evaluation of the kinetics and thermodynamics describing the competition of Zn(2+) against Cd(2+) for GSH from the systematic data obtained by CE-ICP-MS. The competitive binding of Zn(2+) against Cd(2+) for GSH was demonstrated exothermic and thermodynamically favorable (DeltaG = -7.2 kJ/mol) and driven entirely by a large favorable enthalpy decrease (DeltaH = -15.1 kJ/mol) but with an unfavorable entropy decrease (DeltaS = -25.6 J/mol/K). The kinetic data were fit to a second-order equation with the reaction rate constant (k) of (2.18+/-0.10)x10(2) L/(mol x s) under the simulated physiological condition.

A simple chemical etching strategy to generate “ion-imprinted” sites on the surface of quantum dots for selective fluorescence turn-on detecting of metal ions

“…Besides, Zn 2+ can also activate the CdS QDs. 9 To show the role of EDTA and the mechanism of Cd 2+induced fluorescence recovery of the QDs, we used capillary electrophoresis on-line coupled with inductively coupled plasma mass spectroscopy (CE-ICP-MS) 10 to study the speciation of cadmium in the aqueous solution of the QDs before and after EDTA etching (ESIw). Cd 2+ , the Cd-MPA complex and CdTe QDs were found in the solution of the unetched CdTe QDs (Fig.…”

Inorganic species analysis by CE – An overview for 2007–2008

“…CE was shown to preserve the lanthanide aqueous speciation up to the ICP‐MS detector. Another interesting study using CE‐ICP‐MS comprises the competitive binding of zinc and cadmium with glutathione, in which the important kinetic and thermodynamic parameters of this biologically relevant process were determined 147. It is worthwhile to note that that like a good fraction of publications considered in this section, this report is directly related to the field of (bio)speciation analysis.…”

Probing interactions of antimony species with DNA by short column capillary electrophoresis coupled with inductively coupled plasma mass spectrometry

“…A 1/16-inch polyether ether ketone (PEEK) cross fitting was used to connect the make-up solution delivery PTFE tubing, the Pt electrode, the CE capillary and the micro PTFE tubing to the ICP-MS system. 18 To reduce the diffusion of sample zone and to timely transport the separated Sb species in the CE effluent, the capillary was inserted into a micro-PTFE tubing (400-mm i.d. Â 1 mm o.d.)…”