胶束电动毛细管色谱-间接紫外检测法测定糖蜜酒精废液中的有机酸

Determination of Organic Acids in Cane Vinasse by Micellar Electrokinetic Capillary Chromatography with Indirect Ultraviolet Detection

建立了一种利用胶束电动毛细管色谱-间接紫外检测法同时测定丙二酸、甲酸、酒石酸、苹果酸、琥珀酸、戊二酸、乙酸、乳酸和谷氨酸的新方法。以7.5mm o l/L邻苯二甲酸氢钾-1.5mm o l/L十六烷基三甲基溴化铵(用0.1m o l/L氢氧化钠调pH至6.50)混合液作为电泳介质,检测波长为300nm,参比波长为210nm,未涂层弹性石英毛细管(50μm i.d.×64cm)为分离通道,在6m in内实现了9种酸的完全分离。9种有机酸的浓度与其峰面积在一定的范围呈良好的线性关系,检出限均低于1.5m g/L,迁移时间和峰面积的日内、日间相对标准偏差均小于6%。该法用于糖蜜酒精废液中有机酸的测定,结果令人满意,9种有机酸的样品加标回收率均在93%以上。

Micellar electrokinetic capillary chromatography （MECC） with indirect ultraviolet （UV） detection method for the separation and determination of several organic acids in cane vinasse, including malonic, formic, tartaric, malic, succinic, glutaric, acetic, lactic and glutamic acids, were developed. Electrophoretic conditions were as follows： uncoated fused silica capillary （56 cm/ 64 cm（effective/total length）, 50 μm i. d. ）, 7.5 mmol/L potassium acid phthalate-1. 5 mmol/L cetyltrimethyl-ammonium bromide （CTAB） at pH = 6. 50 as buffer solution, applied voltage -25 kV, temperature 25 ℃, detection wavelength 300 nm, reference wavelength 210 nm. Good linearities were obtained for nine organic acids, and the detection limits were 0. 5 mg/L, 0. 3 mg/L, 1.5 mg/L, 1.5 mg/L, 0. 3 mg/L, 0. 3 mg/L, 0. 4 mg/L, 0. 4 mg/L, 0. 4 mg/L for malonic, formic, tartaric, malic, succinic, glutaric, acetic, lactic and glutamic acid, respectively. The relative standard deviations （RSDs） for migration times and peak areas of nine organic acids within a day were 0. 4% - 0. 6% and 2. 3% - 4. 8%, respectively. The corresponding data for five days were 0. 5% - 0. 7% and 3. 3%- 5. 2%. The recoveries of acid standards were above 93%. The method can be applied to determine the organic acids in cane vinasse with satisfactory results.