Sáenz-López Rubén, Fernández-Zurbano Purificación, Tena María Teresa
Department of Chemistry, University of La Rioja, Madre de Dios 51, E-26006 Logroño (La Rioja), Spain.
J Chromatogr A. 2003 Mar 21;990(1-2):247-58. doi: 10.1016/s0021-9673(02)02006-x.
A capillary zone electrophoresis (CZE) method is proposed for the quantitative determination of anthocyanins in wine as an alternative to high-performance liquid chromatography. The CZE separation was carried out using a 46 cm (effective length) x 75 microm I.D. fused-silica capillary at 10 degrees C and a 50 mM sodium tetraborate buffer at pH 8.4 with 15% of methanol as modifier. A voltage of 25 kV and a hydrodynamic injection of 300 mbar s were used. The electropherograms were recorded at 599 nm. It was found that SO2 (antibacterial and antioxidant agent added to wine during its production) increased the absorbance of anthocyanins at 599 nm in a basic medium. Therefore, a concentration of 250 mg/l of SO2 was added to the samples and the calibration solution before the analysis in order to avoid errors by this matrix effect. The analytical response was linear (R=0.998) between 10 and 700 microg/ml of malvidin-3-O-glucoside. The limit of detection and the reproducibility (as a relative standard deviation, n=11) were 1 microg/ml and 1.5%, respectively. Finally, the CZE method was validated by the analysis of synthetic wine samples (errors less than 8%) and by the comparison of the results obtained in the analysis of different monovarietal wines by CZE with those obtained by the standard HPLC method. In this comparison, a good correlation (R=0.998) with a slope of 1.005+/-0.044 and an intercept of -0.752+/-6.690 was obtained for malvidin-3-O-glucoside.
本文提出了一种毛细管区带电泳（CZE）方法，用于定量测定葡萄酒中的花青素，作为高效液相色谱法的替代方法。CZE分离在一根46 cm（有效长度）×75 μm内径的熔融石英毛细管中进行，温度为10℃，使用pH 8.4的50 mM四硼酸钠缓冲液，并添加15%的甲醇作为改性剂。施加25 kV的电压，采用300 mbar s的液压进样。在599 nm处记录电泳图。研究发现，SO2（葡萄酒生产过程中添加的抗菌和抗氧化剂）在碱性介质中会增加花青素在599 nm处的吸光度。因此，在分析前向样品和校准溶液中添加250 mg/l的SO2浓度，以避免这种基质效应造成的误差。在10至700 μg/ml的矢车菊素-3-O-葡萄糖苷范围内，分析响应呈线性（R = 0.998）。检测限和重现性（相对标准偏差，n = 11）分别为1 μg/ml和1.5%。最后，通过分析合成葡萄酒样品（误差小于8%）以及将CZE法分析不同单一品种葡萄酒所得结果与标准HPLC法所得结果进行比较，对CZE法进行了验证。在该比较中，矢车菊素-3-O-葡萄糖苷的相关性良好（R = 0.998），斜率为1.005±0.044，截距为-0.752±6.690。
