University of Campinas, Institute of Chemistry, Campinas, SP, Brazil.
Anal Chim Acta. 2012 Mar 9;718:116-20. doi: 10.1016/j.aca.2011.12.062. Epub 2012 Jan 8.
This work reports an ion chromatographic (IC) method for the quantitative determination of inorganic cations (Na(+), K(+), Mg(2+) and Ca(2+)) in biodiesel samples that were synthesized from different vegetable oils and fat. The proposed method uses water extraction, heating and ultrasound. The limits of detection (LOD) for each ion, in milligrams of the analyte per kilogram of biodiesel (mgkg(-1)), were respectively: 0.11 (Na(+)); 0.42 (K(+)); 0.23 (Ca(2+)); and 0.36 (Mg(2+)). The accuracy of the method was studied through recovery tests. For comparison, two samples were also analyzed using an Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) procedure. The paired Student t test and the Snedecor F test showed that both methods offer equivalent results in terms of accuracy and precision. The operational simplicity, accuracy and precision of the proposed method suggest that it can be a good alternative for the determination of inorganic cations in biodiesel samples.
本工作报道了一种离子色谱（IC）方法，用于定量测定由不同植物油和脂肪合成的生物柴油样品中的无机阳离子（Na(+)、K(+)、Mg(2+)和 Ca(2+)）。该方法采用水提取、加热和超声处理。每种离子的检出限（LOD），以生物柴油中分析物的毫克数表示（mgkg(-1)），分别为：0.11（Na(+)）；0.42（K(+)）；0.23（Ca(2+)）和 0.36（Mg(2+)）。通过回收测试研究了该方法的准确性。为了比较，还使用电感耦合等离子体发射光谱法（ICP-OES）对两个样品进行了分析。配对学生 t 检验和斯奈迪克 F 检验表明，两种方法在准确性和精密度方面均具有等效结果。该方法操作简单、准确且精确，表明它可以成为生物柴油样品中无机阳离子测定的一种良好替代方法。
