direct immersion spme sampling of phytohormones in plants using an aptes-chitosan sorbent followed by hplc-uv quantification

Herein, a simple technique for the extraction and quantification of the phytohormones of gibberellic acid (ga), indole-3-acetic acid (iaa), and abscisic (aba), in plant samples is described 1. a hybrid gel biopolymer, 3-aminopropyltriethoxysilane-chitosan (aptes-cs), was synthesized and coated on a activated titanium substrate and used for direct-immersion solid-phase microextraction (di-spme) of the phytohormones. the analytes were separated and determined using rp-hplc after desorption from the fiber. structural characteristics and surface morphology of the aptes-cs sorbent was studied using fourier transform infrared spectroscopy (ft-ir) and scanning electron microscopy (sem). experimental variables affecting on the extraction efficiency were optimized through response surface methodology through a box-behnken design (bbd). the limits of detection were obtained 0.1 mg/l for ga and aba, and 0.05 mg/l for iaa. calibration graphs were linear over the range of 0.5 - 200 mg/l. the relative standard deviations (rsds, n = 6) for intra-day and inter-days repeatability were obtained 4.32 - 6.3% and 1.31 - 7.33%, respectively. the developed technique was successfully used to analyze phytohormones in plant samples with average recoveries over the range of 80.9 - 118.17%. activation of the fiber substrate created plenty of superficial reactive groups which ensured strong bonding between the substrate and the hybrid gel biopolymer. this fact led to an increased surface porosity, enhanced sorption capability, and high coating durability compare to the reported commercial and homemade fibers, employed for the di-spme sampling 2-4. fiber spme coated with biopolymer aptes-cs used in this work showed high performance and low detection limit which makes it a simple, reliable, fast and cost effective method to determine phytohormones in the plant.