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研究了反相高效液相色谱法同时测定湿地植物根际土壤溶液中11种低分子有机酸的优化方法。探索了柱温、波长、流速、流动相中的pH值以及有机改良剂对检测效果的影响,并进一步验证方法的精密度、加标回收率、检测限等指标。结果表明,采用Waters Atlantis T3 C18(4.6×250 mm,5μm)色谱柱,在柱温为35℃,紫外检测波长210 nm,流动相为磷酸盐缓冲液(0.01 mol/L,pH 2.5)与乙腈(ACN)混合溶液,在流速0.7 m L/min时,进行梯度洗脱分离。该方法加标回收率在95.6%~103.9%,相对标准偏差在0.3%~5.2%,各酸峰面积与质量浓度线性关系良好(R2≥0.999)。该方法成功用于介质复杂的环境样品中低分子有机酸的检测,2014年4月采集的2种湿地挺水植物根际与非根际土壤溶液检测主要存在草酸与丙二酸。芦苇土壤溶液中草酸总计15.83 mg/L,丙二酸总计18.10 mg/L;扁秆藨草土壤溶液中草酸17.90 mg/L,丙二酸总计17.05 mg/L。2种植物中,根际土壤溶液中丙二酸含量均高于非根际土壤溶液。
A reversed phase high performance liquid chromatography method for the simultaneous determination of 11 low molecular weight organic acids in rhizosphere soil of wetland plants was studied. The column temperature, the wavelength, the flow rate, the pH in the mobile phase and the effect of the organic modifier on the detection were explored. The precision, recoveries and detection limits of the method were further validated. The results showed that the UV detection wavelength was 210 nm at a column temperature of 35 ℃ using a Waters Atlantis T3 C18 column (4.6 × 250 mm, 5 μm). The mobile phase consisted of phosphate buffer (0.01 mol / L, pH 2.5) and acetonitrile (ACN) mixed solution, gradient eluted at a flow rate of 0.7 m L / min. The recoveries of this method ranged from 95.6% to 103.9% with relative standard deviations of 0.3% -5.2%. The linear relationship between peak area and mass concentration was good (R2≥0.999). The method was successfully applied to the detection of low molecular weight organic acids in complex environmental samples. In April 2014, two wetland emergent plants mainly contained oxalic acid and malonic acid in the rhizosphere and non-rhizosphere soil samples. In the reed soil solution, total oxalic acid was 15.83 mg / L, malonaldehyde was 18.10 mg / L, oxalic acid was 17.90 mg / L and total malondic acid was 17.05 mg / L. The contents of malonic acid in rhizosphere soil were higher in both species than those in non-rhizosphere soil.