TY - JOUR

T1 - Electromembrane Extraction Using Sacrificial Electrodes

AU - Hansen, Frederik A.

AU - Jensen, Henrik

AU - Pedersen-Bjergaard, Stig

PY - 2020

Y1 - 2020

N2 - In this paper, we report the first example of employing a sacrificial electrode in the acceptor solution during electromembrane extraction (EME). The electrode was based on a silver wire with a layer of silver chloride electroplated onto the surface. During EME, the electrode effectively inhibited electrolysis of water in the acceptor compartment, by accepting the charge transfer across the SLM, which enabled the application of 500 mu A current without suffering gas formation or pH changes from electrolysis of water. The electroplating strategy was optimized with a design-of-experiments (DOE) methodology that provided optimal conditions of electroplating. With an optimized electrode, 1 cm of the electrode in contact with the acceptor solution inhibited electrolysis of water for approximately 30 min at 500 mu A current (redox capacity). Further, the redox capacity of the electrode was found to increase through multiple uses. The advantage of the electrode was demonstrated by extracting polar analytes at high-current conditions in a standard EME system comprising 2-nitrophenyl octyl ether (NPOE) as SLM and 10 mM HCl as sample/acceptor solutions. Application of high current enabled significantly higher recoveries than could otherwise be obtained at 100 mu A Sacrificial electrodes were also tested in mu-EME and were found beneficial by eliminating detrimental bubble formation. Thus, the sacrificial electrodes improved the stability of mu-EME systems. The findings of this paper are important for development of stable and robust systems for EME operated at high voltage/current and for EME performed in narrow channels/tubing where bubble formation is critical.

AB - In this paper, we report the first example of employing a sacrificial electrode in the acceptor solution during electromembrane extraction (EME). The electrode was based on a silver wire with a layer of silver chloride electroplated onto the surface. During EME, the electrode effectively inhibited electrolysis of water in the acceptor compartment, by accepting the charge transfer across the SLM, which enabled the application of 500 mu A current without suffering gas formation or pH changes from electrolysis of water. The electroplating strategy was optimized with a design-of-experiments (DOE) methodology that provided optimal conditions of electroplating. With an optimized electrode, 1 cm of the electrode in contact with the acceptor solution inhibited electrolysis of water for approximately 30 min at 500 mu A current (redox capacity). Further, the redox capacity of the electrode was found to increase through multiple uses. The advantage of the electrode was demonstrated by extracting polar analytes at high-current conditions in a standard EME system comprising 2-nitrophenyl octyl ether (NPOE) as SLM and 10 mM HCl as sample/acceptor solutions. Application of high current enabled significantly higher recoveries than could otherwise be obtained at 100 mu A Sacrificial electrodes were also tested in mu-EME and were found beneficial by eliminating detrimental bubble formation. Thus, the sacrificial electrodes improved the stability of mu-EME systems. The findings of this paper are important for development of stable and robust systems for EME operated at high voltage/current and for EME performed in narrow channels/tubing where bubble formation is critical.

KW - SUPPORTED LIQUID-MEMBRANES

KW - POLAR BASIC DRUGS

KW - PULSED ELECTROMEMBRANE

KW - ELECTROLYSIS

KW - URINE

KW - PLASMA

U2 - 10.1021/acs.analchem.0c00626

DO - 10.1021/acs.analchem.0c00626

M3 - Journal article

C2 - 32202410

VL - 92

SP - 5595

EP - 5603

JO - Industrial And Engineering Chemistry Analytical Edition

JF - Industrial And Engineering Chemistry Analytical Edition

SN - 0003-2700

IS - 7

ER -