基于金属有机骨架材料的磁固相萃取与高效液相色谱-紫外检测法分析饮料和方便面中4种防腐剂

通过简单的搅拌共混方式制备了磁性氨基功能化的金属有机骨架化合物（MOFs）材料，得到的复合材料磁性和热稳定性良好，比表面积大，被用于不同极性防腐剂（苯甲酸、山梨酸、对羟基苯甲酸丙酯和对羟基苯甲酸丁酯）的萃取。优化磁固相萃取及解吸条件后，将解吸液引入高效液相色谱-紫外检测分析仪器，采用Purospher^® STAR LP C18色谱柱（250 mm×4.6 mm，5 μm）分离，以甲醇-10 mmol/L醋酸铵水溶液（50：50，v/v）为流动相进行梯度洗脱。结果表明，目标防腐剂的检出限为0.51~1.89 μg/L；苏打水、维生素饮料和方便面面饼中目标防腐剂的加标回收率为72.2%~109%。该方法简单快速，准确可靠，适用于饮料和食品中不同极性防腐剂的分析，为食品安全及质量监控提供了有效的技术有段。

Analysis of four preservatives in beverages and instant noodle samples by high performance liquid chromatography-ultraviolet detection coupled with magnetic solid phase extraction based on metal-organic frameworks

Magnetic amino functionalized metal-organic frameworks (MOFs) were prepared by a simple stirring and blending process. The obtained composites had good magnetic and thermal stability with a large specific surface area, and were used for the extraction of four preservatives with different polarities (benzoic acid, sorbic acid, propyl p-hydroxybenzoate and butyl p-hydroxybenzoate) in soda water, vitamin beverage and instant noodle cake samples. After optimizing the conditions for magnetic solid phase extraction (MSPE) and desorption, the four preservatives were analysed by a high performance liquid chromatography-ultraviolet detection (HPLC-UV) method. The analytes were separated on a Purospher^® STAR LP C18 column (250 mm×4.6 mm, 5 μm). Methanol and 10 mmol/L ammonium acetate aqueous solution (50:50, v/v) were used as the mobile phases with gradient elution. The limits of detection of the four preservatives were 0.51-1.89 μg/L. The recoveries of the target preservatives were 72.2%-109% in the soda water, vitamin beverage and instant noodle cake samples. The method is simple, rapid, accurate and reliable, and is suitable for the analysis of preservatives with different polarities in beverages and foods. The method can provide an effective technology for food safety and quality control.