García-Marco Sonia, Torreblanca Ana, Lucena Juan J
Sección de Química Agrícola, Universidad Autónoma de Madrid, 28049 Madrid, Spain.
J Agric Food Chem. 2006 Feb 22;54(4):1380-6. doi: 10.1021/jf051745x.
EDDHA/Fe3+ chelates are the most common fertilizers used to solve Fe chlorosis in established crops. Commercial products contain two regioisomers, ethylenediamine-N,N'-bis(o-hydroxyphenylacetic) acid (o,o-EDDHA)/Fe3+ and ethylenediamine-N-(o-hydroxyphenylacetic)-N'-(p-hydroxyphenylacetic) acid (o,p-EDDHA)/Fe3+. Although several chromatographic methods exist for the determination of Fe3+ chelated by the o,o-EDDHA isomer, no method has been described for the quantification of Fe3+ chelated by o,p-EDDHA. In this work, factors that affect the behavior of o,p-EDDHA/Fe3+ in ion pair chromatography are reviewed: pH, ion pair reagent, and organic modifier. The best chromatographic performance was obtained with an aqueous mobile phase at pH 6.0 containing 35% acetonitrile and 5 mM tetrabutylammonium hydroxide under isocratic elution conditions. This method was applied to the quantification of commercial samples.
乙二胺二邻羟苯基乙酸/铁（III）螯合物是用于解决已种植作物缺铁黄化病的最常见肥料。商业产品包含两种区域异构体，即乙二胺-N,N'-双（邻羟基苯基乙酸）（邻，邻-乙二胺二邻羟苯基乙酸）/铁（III）和乙二胺-N-（邻羟基苯基乙酸）-N'-（对羟基苯基乙酸）（邻，对-乙二胺二邻羟苯基乙酸）/铁（III）。尽管存在几种用于测定由邻，邻-乙二胺二邻羟苯基乙酸异构体螯合的铁（III）的色谱方法，但尚未描述用于定量由邻，对-乙二胺二邻羟苯基乙酸螯合的铁（III）的方法。在这项工作中，对影响邻，对-乙二胺二邻羟苯基乙酸/铁（III）在离子对色谱中行为的因素进行了综述：pH值、离子对试剂和有机改性剂。在等度洗脱条件下，使用含35%乙腈和5 mM氢氧化四丁铵的pH 6.0水相流动相可获得最佳色谱性能。该方法应用于商业样品的定量分析。
