[Characteristics and applications of amide bridged calix [ 4 ] arene solid-phase microextraction fiber]

A novel solid-phase microextraction (SPME) fiber coated with 25,27-dihydroxy-26, 28-(1', 10'-dioxa-4', 7'-diaza-3', 8'-dioxooctylene ) -p-tert-butylcalix [ 4 ] arene/hydroxy-terminated silicone oil (amide bridged -C[4]/OH-TSO) was prepared with sol-gel technology and applied to the analysis of aliphatic amines and aromatic amines without derivatization. It demonstrated high thermal stability of up to 380 degrees C and stability in organic and inorganic solvents, a prolonged lifetime of over 200 times for headspace SPME, great fiber-to-fiber reproducibility with a relative standard deviation (RSD) of no more than 6.3% for aromatic amines, etc. Due to the introduction of polar amide bridge in calixarene molecules, polarity of the coating increases and thus the fiber shows better extraction efficiency in most of the investigated aliphatic amines and aromatic amines compared to the extraction efficiency of commercial fibers, indicating specific selectivity and sensitivity to amines. The detection limits (LODs) were determined to be 0.19 - 39.51 microg/L, the linear ranges were 3 orders of magnitude with a precision better than 5.1% for aliphatic amines, and they were 1.21 - 40.73 ng/L, 4 - 6 orders of magnitude with a precision better than 6.0% for aromatic amines. The application of this SPME technique coupled with gas chromatography has been shown to be feasible for the rapid determination of fish freshness.