The facile preparation and characterization of a cationic polyelectrolyte (polydiallyldimethylammonium chloride, PDDA) fabricated graphene oxide-grafted silica microsphere (PDDA@GO@Sil) with high positive charge density as the sorbent for the high selective capture of acidic herbicides were reported. The theoretical calculation showed that there were strong adsorption energies between the PDDA and analytes, and the main interaction was the hydrogen bonding from OH…Cl and CO…HC. Static- and dynamic- state adsorption results indicated that acidic herbicides were the monolayer coverage onto the PDDA@GO@Sil due to the electrostatic attraction between the sorbent and analytes, and electrostatic repulsion among analytes. Under the optimized conditions obtained with the single-factor experiment and response surface methodology, this established method was used for the enrichment and determination of herbicides in two vegetables. Method detection limits were in the range of 0.75-1.50 µg L-1 indicating that the introduction of PDDA provided the excellent extraction capacity toward acidic herbicides. The obtained results exhibited that the developed method was feasible, reliable, selective and accurate for the determination of acidic herbicides in real samples.

中文翻译：

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阳离子聚电解质/氧化石墨烯作为一种有效的吸附剂，可用于蔬菜中痕量酸性除草剂的提取和分析。

报道了一种阳离子聚电解质（聚二烯丙基二甲基氯化铵，PDDA）的制备方法和表征，这些阳离子聚电解质是氧化石墨烯接枝的二氧化硅微球（PDDA @ GO @ Sil），具有高正电荷密度，可以作为吸附剂，用于高选择性地捕获酸性除草剂。理论计算表明，PDDA与分析物之间具有很强的吸附能，主要的相互作用是OH…Cl和CO…HC的氢键。静态和动态状态的吸附结果表明，由于吸附剂和分析物之间的静电吸引以及分析物之间的静电排斥，酸性除草剂被单层覆盖在PDDA @ GO @ Sil上。在通过单因素实验和响应面方法获得的最佳条件下，该既定方法用于两种蔬菜中除草剂的富集和测定。方法检测限在0.75-1.50 µg L-1范围内，这表明PDDA的引入提供了对酸性除草剂的出色提取能力。所得结果表明，所建立的方法用于实际样品中酸性除草剂的测定是可行，可靠，选择性和准确的。