Electrophoretic analysis of polyamines in exhaled breath condensate based on gold-nanoparticles microextraction coupled with field-amplified sample stacking

Abstract

In this work, citrate-capped gold-nanoparticles (citrate-AuNPs) have been firstly used for selective extraction of trace polyamines, putrescine (Put) and cadaverine (Cad), followed by field-amplified sample stacking (FASS) coupled with capillary electrophoresis and capacitively coupled contactless conductivity detection (FASS-CE-C4D). Put and Cad were extracted by electrostatic attractions between the amine group of the polyamines and the citrate ligands adsorbed on the surfaces of AuNPs. AuNPs microextraction (AuNPs-ME) effectively shortened preparation time (50 min) by introducing ultrasound, and the required sample extraction volume was only 1 mL. Furthermore, a synergistic enrichment strategy based on off-line AuNPs-ME and on-line FASS significantly improved the detection sensitivity, making the enrichment factors up to 1726–1887 times. Under the optimum conditions, Put and Cad could be well separated from the potential coexisting substances and then directly determined by CE-C4D without derivatization. Due to its low sample consumption, high sensitivity (LODs: 0.070–0.17 ng mL−1), and acceptable recoveries (90–105%), this AuNPs-ME/FASS-CE-C4D method provides a rapid, economical and eco-friendly approach for direct determination of polyamines in human exhaled breath condensate, and has potential application prospects in preliminary noninvasive diagnosis of oral and respiratory inflammation.