Combined use of supported liquid membrane and solid‐phase extraction to enhance selectivity and sensitivity in capillary electrophoresis for the determination of ochratoxin A in wine

Abstract

This paper proposes a novel strategy to enhance selectivity and sensitivity in CE, using supported liquid membrane (SLM) and off-line SPE simultaneously. The determination of ochratoxin A (OA) in wine has been used to demonstrate the potential of this methodology. In the SLM step, the donor phase (either a 20 mL volume of a standard solution at pH 1 or a wine sample at pH 8) was placed in a vial, where a micromembrane extraction unit accommodating the acceptor phase (1 mL water, pH 11) in its lumen was immersed. The SLM was constructed by impregnating a porous Fluoropore Teflon (PTFE) membrane with a water-immiscible organic solvent (octanol). In the off-line SPE step, the nonpolar sorbent (C-18, 4 mg) selectively retained the target ochratoxin, enabling small volumes of acceptor phase (1 mL) to be introduced. The captured analytes were eluted in a small volume of methanol (0.1 mL). This procedure resulted in sample cleanup and concentration enhancement. The method was evaluated for accuracy and precision, and its RSD found to be 5%. The LODs for OA in the standard solutions and wine samples were 0.5 and 30 microg/L, respectively. The results obtained demonstrate that SLM combined with off-line is a good alternative to the use of immunoaffinity columns prior to CE analysis.

Determination of Ochratoxin A in Food by High Performance Liquid Chromatography

“…Other applied techniques for OTA determination are high performance thin layer chromatography (HPTLC) (Welke et al 2010), gas chromatography coupled with MS (GC-MS) (Olsson et al 2002), enzyme immunoassay (EIA) (Saha et al 2007), and fluorescence polarization immunoassay (Zezza et al 2009). Also, capillary electrophoresis (CE) with UV=Vis detection has also been proposed for the determination of OTA in wine (Almeda, Arce, and Valcárcel 2008;González-Peñ as et al 2006). The use of laser induced fluorescence (LIF) as a more sensitive detection system has been proposed for the determination of OTA in different food samples (roasted coffee, corn, and sorghum) using capillary electrophoresis (Corneli and Maragó s 1998) and in wine (ArroyoManzanares, Gámiz-Gracia, and García-Campaña 2012).…”

Alternatives for sample pre-treatment and HPLC determination of Ochratoxin A in red wine using fluorescence detection

“…However, although sufficient selectivity was obtained, a lower sensitivity than the IAC treatment was observed [15]. Other techniques, like Capillary Electrophoresis, have been evaluated, obtaining unfavorable sensitivities [16][17][18][19]. Consequently, this technique is not appropriate to determine OTA in wine, considering the concentration levels commonly found [15,20].…”

Capillary Electrophoresis as a Promising Technique to Evaluate Metabolites Secreted by Fungal Biocontrol Agents

“…In order to choose a suitable buffer to detect dtxs, different buffers previously used to separate other mycotoxins were taken into account [22][23][24][25]. The best conditions were achieved using micellar electrokinetic chromatography (MEKC) with a mixture of sodium tetraborate, SDS and a basic pH.…”