Room temperature ionic liquids (RTILs), as novel solvents, have many fascinating properties which make them of fundamental interest to all chemists. Herein, we report the first application of an RTIL in the chemical vapor generation (CVG) of transition and noble metals following reduction of acidified analyte solution with KBH4. Copper, silver and gold were selected as model analytes, and N-butylpyridinium tetrafluoroborate ([N bupy][BF4]) was used as a model RTIL. The RTIL-enhanced CVG of copper, silver and gold was evaluated by flow injection atomic fluorescence spectrometry (FI-AFS). The addition of [N bupy][BF4] leads to a 4.8-, 2.7- and 3.6-times improvement in the CVG efficiencies for copper, silver and gold, respectively. Interference from Zn(II), Fe(III), Co(II), Ni(II), Pb(II), Se(IV) and As(III) was also reduced in the presence of [N bupy][BF4]. The role of the RTIL was supposed to be inhibition of further coalescence of the metal nanoparticles which may constitute the volatile metal species leaving the solution and/or reaching the atomizer, and hence prevention of the loss of volatile metal species. With the consumption of a 0.5 mL sample solution, the detection limits (3s) for Cu, Ag and Au are 19, 15 and 6.3

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 Zn2+ against Cd2+ for glutathione (GSH), which is related to the detoxification of Cd2+ in biological system, and introduce a method to evaluate the kinetics and thermodynamics for the competitive binding of Zn2+ against Cd2+ for GSH. The CE-ICP-MS hybrid technique allows easy and sensitive probing of the competitive binding of Zn2+ against Cd2+ for GSH and quantitative determination of the important thermodynamic and kinetic parameters of the competitive binding of Zn2+ against Cd2+ 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 Zn2+ against Cd2+ for GSH from the systematic data obtained by CE-ICP-MS. The competitive binding of Zn2+ against Cd2+ for GSH was demonstrated exothermic and thermodynamically favorable (△G = -7.2 kJ/mol) and driven entirely by a large favorable enthalpy decrease (△H = -15.1 kJ/mol) but with an unfavorable entropy decrease (△S = -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)×102 L/(mol·s) under the simulated physiological condition.

We report an ion imprinted mesoporous silica based fluorescence turn-on sensor array for discrimination of metal ions. A novel fluorescent functional monomer containing an 8-hydroxyquinoline (8-HQ) moiety in combination with one-pot co-condensation method was employed to prepare fluorescent ion imprinted mesoporous silica. The imprinted materials for Zn2+ and Cd2+ as well as a control blank nonimprinted material (NIM) were synthesized. With the covalently anchored organic fluorophore in the inorganic mesoporous silica matrix, the binding of metal ions to the imprinting site was directly transformed into fluorescence signals. Both the imprinted materials displayed faster binding kinetics toward metal ions than NIM. Apparent binding constants (adsorption constants) for the materials with the metal ions in water were determined by a Langmuir-type analysis of the spectrofluorimetric titration data. The sensor array composed of the three materials allows discriminating the two template metal ions (Zn2+ and Cd2+) plus three non-template metal ions (Mg2+, Ca2+ and Al3+) at two different concentrations. This work proves that using a simple fluorescent receptor can provide a pattern based fluorescent sensing system by taking advantage of the imprinting effect.

To get insight into the mechanism of the effect of room-temperature ionic liquids (RTILs) on the chemical vapor generation (CVG) of noble metals, gold was taken as a model element, and eight RTILs were examined. All the RTILs resulted in 3–24 times improvement in sensitivity for Au, depending on their nature. For the RTILs with identical anion, the RTILs with the cations of short chain exhibited better enhancement effect than those with long alkyl chain length or complex branch chain. For the RTILs with identical cation, the RTILs with Br− gave the best enhancement effect. The formation of ion pairs between the cation of RTILs and the anion species of gold via electrostatic interaction, and/or the substitution of the Cl− in the anion species of gold by the anion of RTILs likely enabled a more effective CVG reaction to occur. The RTILs also facilitated the generation of small bubbles and provided an electrostatic stabilization to protect the unstable volatile gold species and to help fast isolation of volatile gold species from the reaction mixture. 1-Butyl-3-methylimidazolium tetrafluoroborate [C4mim]Br gave the best improvement in the sensitivity (24 times) among the RTILs studied, and also reduced the interferences fromcommontransition and other noble metals. Based on the enhancement effect of [C4mim]Br, a novel flow injection–CVG–atomic fluorescence spectrometric method with a detection limit (3s) of 1.9 µgL−1 and a precision of 3.1% (50 µgL−1, RSD, n = 11) was developed for the determination of trace gold in geological samples.