Miniaturized molecularly imprinted matrix solid-phase dispersion coupled with high performance liquid chromatography for rapid determination of auxins in orange samples

A simple, convenient and high selective miniaturized molecularly imprinted matrix solid-phase dispersion (mini-MI-MSPD) technique using l-tryptophan-imprinted polymers as sorbents was proposed for simultaneous extraction of four auxins (indole-3-acetic acid (IAA), indole-3-propionic acid (IPA), indole-3-butyric acid (IBA) and 1-naphthaleneacetic acid (NAA)) from orange samples coupled with high performance liquid chromatography–ultraviolet detection. The molecularly imprinted polymers (MIPs) synthesized using l-tryptophan as dummy template showed high affinity and selectivity to auxins, and so they were applied as the specific dispersant of MSPD to simultaneously eliminate the effect of template leakage on quantitative analysis. Under the optimized conditions, good linearity was obtained in a range of 0.02–2.00 μg g−1 and the average recoveries of four auxins at three spiked levels ranged from 87.6% to 104.5% with the relative standard deviation (RSD) ≤4.4%. The presented mini-MI-MSPD method combined the advantages of MSPD for allowing the extraction, dispersion and homogenization in a single step and the advantages of MIPs for high affinity and selectivity towards four auxins, which could be applied to the determination of auxins in complicated vegetal samples.

► A simple and rapid mini-MI-MSPD method for isolation of auxins in orange.
► MIP synthesized by tryptophan as dummy template show high affinity to auxins.
► Rapid screening of four auxins from orange samples with improved purification effect.
► Extraction efficiency was markedly increased with reduced equilibrium time.
► The mini-MI-MSPD–HPLC method improved the selectivity and eliminated the effect of template leakage on quantitative analysis.