The polyaniline-coated magnetite/silica nanomaterials (Fe₃O₄@SiO₂/PANI) have been synthesized and successfully applied as an effective sorbent for preconcentration of several typical organic acids from environmental water samples. The properties of Fe₃O₄@SiO₂/PANI are characterized by FT-IR and XPS. These magnetic materials can enrich trace organic acids effectively by solid-phase extraction. Three kinds of organic acids, including benzoic acids, phthalic acids, and p-toluene sulfonic acids, are selected as target analytes for magnetic solid phase extraction (MSPE). Various experimental parameters of the MSPE were investigated and optimized. After the desorption process, the elution is detected by the UV-visible spectrophotometer. The spectroscopic data are analyzed through the partial least squares (PLS) method, which facilitate quantitation of mixture from complex data. The enrichment factor of benzoic acids, phthalic acids and p-toluene sulfonic acids reached 19.53, 20.31, and 16.89, respectively. A wide measurement range of 10 μg L^-1 to 50 mg L^-1 is obtained. The LOD is 0.8 μg L^-1. The spiked recoveries in the range of 94%-101% with RSD (n=8) lower than 4%. The results illustrated that the combined approach of MSPE and PLS has great applied potential for a mixture of trace compounds in different fields because of its high efficiency, easy to operate conditions, speediness, and simplicity.

中文翻译：

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磁性固相萃取-化学计量学同时测定水样中的痕量混合有机酸

合成了聚苯胺包覆的磁铁矿/二氧化硅纳米材料（Fe ₃ O ₄ @SiO ₂ / PANI），并成功地用作有效富集剂，用于从环境水样品中预浓缩几种典型的有机酸。用FT-IR和XPS表征了Fe ₃ O ₄ @SiO ₂ / PANI的性能。这些磁性材料可以通过固相萃取有效地富集微量有机酸。三种有机酸，包括苯甲酸，邻苯二甲酸和对苯二甲酸选择甲苯磺酸作为磁性固相萃取（MSPE）的目标分析物。对MSPE的各种实验参数进行了研究和优化。解吸过程后，通过紫外可见分光光度计检测洗脱。通过偏最小二乘（PLS）方法分析光谱数据，这有助于从复杂数据中定量混合物。苯甲酸，邻苯二甲酸和对甲苯磺酸的富集系数分别达到19.53、20.31和16.89。获得了10μgL ^-1至50 mg L ^-1的宽量程。LOD为0.8μgL ^-1。RSD的加标回收率在94％-101％范围内（n= 8）低于4％。结果表明，MSPE和PLS的组合方法具有高效，易于操作的条件，快速且简便的特点，因此在不同领域中的痕量化合物混合物具有巨大的应用潜力。