Packed hybrids of gold nanoparticles and halloysite nanotubes for dispersive solid phase extraction of triazine herbicides, and their subsequent determination by HPLC

Halloysite nanotubes (HNTs) were functionalized with gold nanoparticles. The morphology and structures of this composite were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, powder X-ray diffraction, and surface area and pore-size analyses. The material was employed, in conjunction with a syringe pump and an organic filter head, to the enrichment of five triazines (atrazine, desmetryn, prometorn, tebumeton, ametryn) in spiked rice samples. Several parameters that may affect the extraction efficiencies, including type and volume of extraction solvent, amount of sorbent, times of ultrasonic extraction and adsorption, volume and flow rate of elution solvent, were optimized. Following elution with acetonitrile, the herbicides were quantified by using HPLC. Under the optimum conditions, the LODs of the method, when applied to spiked rice samples, are the range from 0.06 to 1.32 ng g⁻¹ (LODs = 3SD/k). The relative intra-day and inter-day recoveries ranged from 80.6 to 106.5% and 80.4–107.3%, respectively, and relative standard deviations ranged from 0.8 to 8.7% and 3.6–9.6%, respectively. [Figure not available: see fulltext.].