抑制型离子色谱法检测植物样品中植酸根及磷酸根的含量

采用抑制型高效离子色谱法检测植物样品中植酸根和磷酸根的含量。样品用1%(质量分数)三氯乙酸处理,离心沉降 后取上清液经0.45 μm微孔滤膜过滤后注入离子色谱仪。用0.22 mol/L氢氧化钠水溶液、水和50%(体积分数)异丙醇水 溶液进行梯度淋洗,经微膜抑制后检测其电导率。实验结果表明,植酸根与磷酸根的检测不受F-、Cl-、SO2-4、NO-3、CC l3CO-2等阴离子的干扰。植酸根、磷酸根的质量浓度分别为5~400 mg/L和5~500 mg/L 时与峰面积呈良好的线性关系(r2分别为0.9994和0.9999),检出限分别为3.5 mg/L和1.5 mg/L;植酸根、磷酸根的平均 回收率分别为99.8%和98.4%,检测结果的相对标准偏差分别为1.98%和2.09%。

Determination of Phytate and Phosphate in Plant Samples by Suppressed Conductivity Ion

Determination of phytate and phosphate by suppressed conductivity ion chromatography was investigated. Plant samples were extracted with 1% (mass fraction) trichloroacetic acid (TCA). After centrifugal settling, the supernatant was filtered with a 0.45 microm filter membrane before injected into the ion chromatographic system and detected by suppressed conductivity. The gradient eluent was composed of 0.22 mol/L sodium hydroxide solution, water and 50% (v/v) isopropyl alcohol solution. Phytate and phosphate were determined within 15 min, and no interference was found in the presence of fluorate, chlorate, nitrate, sulphate and TCA. Good linearities for phytate and phosphate were obtained in the ranges of 5-400 mg/L (r2 = 0.9994) and 5-500 mg/L (r2 = 0.9999), and the detection limits (S/N = 3) were 3.5 mg/L and 1.5 mg/L, respectively. The average recoveries for phytate and phosphate were 99.8% and 98.4%, and their relative standard deviations were 1.98% and 2.09%, respectively.