纳米氧化铟改性的碳纳米管吸附剂的制备及其在食品防腐剂检测中的应用

Preparation of Indium Oxide Functionalized Multiwalled Carbon Nanotube Adsorbent for Detection of Preservatives in Food Samples

建立了以氧化铟(In_2O_3)纳米粒子改性的多壁碳纳米管(In_2O_3-MWCNTs)为固相萃取吸附剂,与高效液相色谱联用,同时检测红酒及果汁中3种防腐剂(苯甲酸、山梨酸和尼泊金甲酯)的研究方法。本研究利用In_2O_3纳米粒子较大的比表面积及所含丰富的基团,以及碳纳米管良好的热稳定性和化学稳定性,制备了In_2O_3-MWCNTs吸附剂。分别采用透射电镜、热重分析及傅立叶变换红外光谱对吸附剂进行表征,通过正交实验得到最优萃取条件为:吸附剂用量0.15 g、样品体积5.0 m L、洗脱液为ACN-H_2O(60∶40,0.1%甲酸,V/V)、洗脱液体积0.6 m L、样品p H=4.0。在最佳萃取条件下,3种防腐剂的方法检出限为0.004~0.012μg/m L,定量限为0.012~0.038μg/m L,样品加标回收率为70.2%~109.4%。本方法快速、灵敏,能够满足食品样品中防腐剂含量的检测要求。

In_2O_3nanoparticles-modified multiwalled carbon nanotubes( In_2O_3-MWCNTs) were successfully prepared as solid phase extraciton( SPE) adsorbent for the determination of three food preservatives( benzoic acid,sorbic acid, and methylparaben) in beverage samples coupled with high performance liquid chromatography( HPLC). Because of the large surface area and amount of hydroxyl groups on the surface of In_2O_3 nanoparticles, In_2O_3 nanoparticles could interact with specific functional groups. In_2O_3-MWCNTs adsorbent was prepared based on the large surface area of In_2O_3 and superior thermal and chemical stability of MWCNTs. The obtained adsorbent was characterized via transmission electron microscope( TEM),thermogravimetric analysis( TGA), and Fourier transform-infrared( FT-IR) spectroscopy. Several experimental parameters affecting the extraction efficiency were investigated by single-factor experiments,such as adsorbents amount,sample volume,eluent volume,sample p H,and eluent type. The first four factors were then further evaluated by means of a Taguchi's L16( 44) orthogonal array experimental design. According to the results of orthogonal array experiment,the optimal conditions were chosen as follows: 0. 15 g of adsorbent amount,5.0 m L of sample volume,0.6 m L of ACN-H_2O( 60∶ 40,0.1% formic acid,V/V) as eluent,and sample p H 4. 0. Under the optimum conditions,the LODs( S/N = 3) and LOQs( S/N = 10) for three preservatives were in the range of 0.004-0.012 μg/m L and 0.012-0.038 μg/m L,respectively. The recoveries ranged from 70. 2% to 109. 4%. The method is rapid,sensitive,and suitable for the determination of preservatives in food samples.