Analytical techniques for analyte quantification are often complex, time-consuming, and costly. Further, samples must be carefully prepared to make them suitable for each analytical technique, thus increasing complexity and cost and often requiring toxic solvents. In this paper, we propose a simple and quick method for the pre-concentration of analytes using a nonporous adsorbent: nanosilica, which is prepared from rice husks, an ecofriendly waste material. Subsequently, analysis using high-performance liquid chromatography with a photodiode array detector was used for accurate analyte quantification. To test our method, Sudan I and II dyes were selected because these are potential carcinogens that are often used to adulterate foods because of their bright colors. Although nanosilica has been used as an adsorbent before, the adsorption of hydrophobic organic dyes has not been investigated to date. Thus, the optimal conditions for dye adsorption on nanosilica were systematically studied and found to be 1 mM KCl, pH 3.0, and an adsorption time of 120 min, and the maximum adsorption capacities of the nanosilica for Sudan I and II were 0.619 and 0.699 mg·g⁻¹, respectively. The adsorption of the dyes on the nanosilica is discussed in detail with respect to the surface area, functional groups, zeta potential, and adsorption isotherms. Under optimal conditions, the extraction efficiencies of Sudan I and Sudan II reached 98.3% and 92.8%, respectively, and the proposed method was applied for the analysis of several foods and achieved high recoveries (80–100%).

中文翻译：

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纳米硅胶同时吸附-高效液相色谱法测定食品中的苏丹I和II

用于分析物定量的分析技术通常是复杂，费时且昂贵的。此外，必须仔细准备样品以使其适合每种分析技术，从而增加了复杂性和成本，并经常需要使用有毒的溶剂。在本文中，我们提出了一种使用无孔吸附剂进行纳米颗粒预富集的简单，快速的方法：纳米二氧化硅是由稻壳（一种环保废料）制备的。随后，使用带有光电二极管阵列检测器的高效液相色谱进行分析，以进行准确的分析物定量。为了测试我们的方法，选择了苏丹I和II染料，因为它们是潜在的致癌物质，由于其色泽鲜艳，经常被用于掺假食品。尽管以前纳米二氧化硅已被用作吸附剂，迄今为止，尚未研究疏水性有机染料的吸附。因此，系统地研究了染料在纳米二氧化硅上吸附的最佳条件，发现该条件为1 mM KCl，pH 3.0，吸附时间为120分钟，该纳米二氧化硅对苏丹I和II的最大吸附容量为0.619和0.699 mg ·G^-1。关于表面积，官能团，ζ电势和吸附等温线，详细讨论了染料在纳米二氧化硅上的吸附。在最佳条件下，苏丹I和苏丹II的提取效率分别达到98.3％和92.8％，所提出的方法用于几种食品的分析，回收率很高（80-100％）。