, 2008 and Teixidó et al., 2011). Capillary electrophoresis

has been applied to 5-HMF determination employing the micellar electrokinetic capillary chromatography (MEKC) mode. Morales and Jiménez-Pérez (2001) developed a procedure for determining HMF in milk-based products using MEKC and compared with the classical reversed-phase HPLC method it gives similar values of repeatability and recovery. The 5-HMF peak was resolved using an uncoated fused-silica capillary with phosphate buffer containing sodium dodecyl sulphate (SDS) (pH 7.5), and separation was completely achieved in 5 min. Silva et al. (2008) applied MEKC for the determination of 5-HMF in honey samples within 5 min. The recovery was 98%

and the limit of detection was 0.025 mg kg−1. More recently, Teixidó et al. (2011) found LY294002 chemical structure 5-HMF in several foodstuffs, Gefitinib chemical structure and the MEKC method (analysis time of 6 min) was compared with the results obtained by liquid chromatography, coupled to tandem mass spectrometry. The sample limit of detection (LOD, 0.7 mg kg−1) and limit of quantification (LOQ, 2.5 mg kg−1) were established by preparing the standards in a blank matrix. This study attempted to design a rapid method for the determination of 5-HMF in honey samples, using a MEKC methodology with a 32 factorial design and electrolytes composed of tetraborate/SDS and modified by methanol. The method performed under the optimised much conditions was validated and further applied in the determination of 5-HMF in honey samples of different geographical and botanical origins. No reports of a

method faster than that presented in this paper using capillary electrophoresis can be found in the literature. The CE assays were conducted in a capillary electrophoresis system (model 7100, Agilent Technologies, Palo Alto, CA, USA), equipped with a diode array detector set at 284 nm, a temperature control device maintained at 25 °C and acquisition and data treatment software supplied by the manufacturer (HP ChemStation, rev. A.06.01). An uncoated fused-silica capillary (Polymicro Technologies, Phoenix, AZ, USA) was used, with dimensions of 32.0 cm total length, 8.5 cm effective length, an inner diameter of 50 μm and an outer diameter of 375 μm. The background electrolyte (BGE) was composed of 5 mmol L−1 STB at pH 9.3 containing 120 mmol L−1 SDS. At the beginning of each day, the capillary was conditioned by flushing with 1 mol L−1 NaOH (10 min) followed by a 10 min flush with deionised water and BGE solution (15 min). In between runs, the capillary was reconditioned with the background solution (1 min flush). At the end of each working day, the capillary was rinsed with 1 mol L−1 NaOH (5 min) and water (10 min) and then dried with air (2 min).