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目的建立高效离子色谱法测定淀粉中的顺丁烯二酸。方法样品加水混匀然后用离心机(3000 r/min)离心分离,取上清液过0.22μm滤膜后最过On-Guard RP小柱后进样分析。分离方法采用阴离子色谱柱IonPac AS22分离柱(250 mm×4 mm)和IonPac AG22保护柱(50 mm×4 mm),以4.5 mmol/L Na2CO31.4 mmol/L NaHCO3等度淋洗,进样量25μl,在流速1.0 ml/min的条件下,测定淀粉样品中顺丁烯二酸的含量。结果在0.05 mg/L~100 mg/L范围内线性关系良好,回归方程的线性相关系数为0.9999,在添加10 mg/kg、100 mg/kg、500 mg/kg 3个水平含量的马来酸,样品加标回收率在91%~95%之间,以信噪比(S/N)分别为3时和10时,检出限为0.83 mg/kg,定量限2.8 mg/kg。结论该方法具有灵敏度高,操作简单,重复性好等特点,能够快速准确测定淀粉中的顺丁烯二酸。
Objective To establish a high performance ion chromatography for the determination of maleic acid in starch. Methods The samples were mixed with water and then centrifuged with a centrifuge (3000 r / min). The supernatant was passed through a 0.22 μm membrane filter and then analyzed by On-Guard RP column. The separation method was performed on an anion column IonPac AS22 column (250 mm × 4 mm) and IonPac AG22 guard column (50 mm × 4 mm) with an isocratic elution of 4.5 mmol / L Na2CO3 and 7.4 mmol / L NaHCO3. The injection volume 25 μl, the maleic acid content in the starch sample was measured at a flow rate of 1.0 ml / min. The results showed good linearity in the range of 0.05 mg / L to 100 mg / L with a linear correlation coefficient of 0.9999 for the regression equation. After adding 10 mg / kg, 100 mg / kg and 500 mg / kg of maleic acid The recoveries of spiked samples ranged from 91% to 95%. The detection limit was 0.83 mg / kg and the limit of quantification was 2.8 mg / kg when the S / N ratios were 3 and 10, respectively. Conclusion The method has the characteristics of high sensitivity, simple operation and good repeatability. It can quickly and accurately determine maleic acid in starch.