离子色谱-在线柱后电化学衍生-荧光法测定酪氨酸

采用自制电解池作为电化学衍生装置，建立了离子色谱一电化学衍生一荧光法测定饮料中的酪氨酸。在碱性淋洗液作用下，酪氨酸在阴离子交换柱上被分离，到达自制电解池的阳极室，在阳极上被氧化，氧化后的产物因具有较强的荧光而被荧光检测器检测。离子化试剂既可以做色谱分离所需的淋洗液，又可以作为电化学反应优良的支持电解液，因此，离子色谱和电化学衍生具有较好的兼容性。最佳的实验条件为：淋洗液NaOH（10mmol／L）＋乙腈（ACN，1＋9），流动相流速1．0mL／min，电解池电压1．0V，激发／发射波长320／420NM。在优化的实验条件下，酪氨酸的线性范围为0．01～10mg／L，检出限为1．2μg／L（信噪比S／N=3）。50μg／L的酪氨酸标准溶液进样7次，得到的色谱峰面积相对标准偏差为2．5％。方法具有快速，灵敏和选择性好的特点，并成功用于饮料中酪氨酸的测定。

Determination of Tyrosine by the Combination of Ion chromatography, online Post-column Electrochemical Derivatization and Fluorescence spectrometry

Using a self-constructed electrolytic cell for electrochemical derivatization treatment, a novel method based on ion chromatography combined with online post-column electrochemical derivatization and fluorescence detection was developed for the determination of tyrosine. Following the separation on the anion exchange column with alkaline eluent, tyrosine was introduced to the anode chamber of the electrolytic cell for electro-oxidization, of which oxidization product has strong fluorescence yield thus can be easily detected by fluorescence detector. Ionization reagent was used both as the eluent for separation and the supporting electrolyte for electrochemical reaction, which guarantee the good compatibility between the ion chromatography and post-column electrochemical derivatization. The optimal experimental conditions are as follows： eluent of NaOH（10 mmol/L）＋acetonitrile（l＋9）, flow rate of 1.0 mE/rain, electro oxidation potential of 1.0 V, excitation and emission wavelength of 320 nm and 420 nm, respectively. Under these optimal experimental conditions, the linear range of tyrosine was from 0.01 to 10 mg/L and the detection limit was 1.2 μg/L with the signal-to noise ratio of 3. After seven replicate injections of 50 μg/L tyrosine, the relative standard deviation of the chromatogram peak area was 2.5%. The method has advantages of rapidity, high sensitivity and good selectivity and was successfully applied for the determination of tyrosine in drink.