Determination of alkali metal ion transfers at liquid|liquid interfaces stabilized by a micropipette

A Newly Synthesized Tris(crown ether) Ionophore for Assisted Ion Transfer at NanoITIES Electrodes

“…We applied this tris(crown ether) ionophore for the amperometric detection of ionic species using nanoITIES electrodes, including Mg 2+ , Cu 2+ , Cd 2+ , Li + , and dopamine. While the detection of Mg 2+ , Cu 2+ , Cd 2+ , Li + , and dopamine facilitated by mono(crown ether) at ITIES electrodes have been reported, their amperometric detection facilitated by tris(crown ether) is presented here for the first time. We further measured the stoichiometric coefficients, Gibbs free energy, and binding constants for the ionic complexations with tris(crown ether), TriBCE , using theory developed by Girault and colleagues, and used by others .…”

“…An Ag wire (diameter=250 μm) coated with AgCl (through an oxidation reaction in saturated KCl solution) was placed in the aqueous phase as an outside reference electrode. A two electrode configuration was used as reported previously, where a potential was applied between the inner Pt wire and the outer Ag/AgCl reference electrode . Positive potential is for positive ion transfer from water to oil (1, 2‐DCE), seen as positive current.…”

“…The detection of ionic species with ITIES electrodes is based on the potential driven ion transfer across the polarized interface, which is related to the structure and hydrophilicity of each analyte, following the Nernstian equation . Ions transfer either directly across ITIES without an ionophore, or through its complexation with an ionophore, which is known as the assisted ion transfer . A commonly used ionophore in ITIES is dibenzo‐18‐crown‐6 (DB18C6) .…”

“…[36,37] Ions transfer either directly across ITIES without an ionophore, or through its complexation with an ionophore, which is known as the assisted ion transfer. [9,15,16,[18][19][20][21][38][39][40][41][42][43] A commonly used ionophore in ITIES is dibenzo-18-crown-6 (DB18C6). [9,18,[23][24][25][26]40,41,43] Although great progress has been made in synthesizing ionophores with multiple crown either moieties for ion selective electrodes, [44][45][46][47] such ionophores have yet to be tested for amperometric ion detection at ITIES electrodes.…”

Preparation and crystal structure of tetraoctylphosphonium tetrakis(pentafluorophenyl)borate ionic liquid for electrochemistry at its interface with water

“…For this blank case, the sharp increase (at positive potentials) or decrease (at negative potentials) marks the edge of the polarizable potential window (PPW), which is limited by the transfer of the supporting electrolyte/analyte from the aqueous phase, or the anionic/cationic component of the IL phase. For example, at the positive end this is either K + transfer for aqueous to IL (w to IL) or the anionic component of the IL, B(C6F5)4 -, from IL to w; while at the negative end, this is either NO3from w to IL or P8888 + from IL to w. Owing to the extreme hydrophobicity of the IL components [3,32], it is likely that change in current is due to K + and NO3transfer. In Figure 1B, using Cell 2, when the potential was swept from negative to positive potentials, a peak-shaped wave indicative of N(CH3)4 + transfer from w to IL was observed at a peak potential of 0.298 V. Upon reversal of the scan direction, a second peak-shaped wave can be seen at 0.170 V and is the result of N(CH3)4 + transfer back from IL to w. These peakshaped ion transfer (IT) waves are owing to two factors: (1) the geometric confinement of the aqueous phase within the micro-channel of the pulled pipette for the w to IL transfer wave;…”