Study On Trace Bioanalytical Methods Based On Gold-Nanoparticales Selective Extraction Coupled With Electrophoretic Technology

1.PrefaceCapillary electrophoresis(CE)has become a versatile,extensive,and sophisticated separation technique.Capacitively coupled contactless conductivity detection(C~4D)is a kind of universal detection technology for CE.So,CE-C~4D has a wide application prospect in biological and environmental analyses.For the analytical substances with complex matrix and low contents,sample pretreatment has become an indispensable procedure for chromatographic analysis in order to improve sensitivity.In this chapter,CE-C~4D and its application were briefly reviewed,and then the advances of solid phase microextraction techniques and their adsorbent materials were highlighted.2.Trace Analysis of Biological polyamines by AuNPs-ME/CE-C~4D methodIn this work,citrate-capped gold-nanoparticles(citrate-AuNPs)have been frstly used for selective extraction of trace polyamines,putrescine(Put)and cadaverine(Cad),followed by feld-amplifed sample stacking(FASS)coupled with capillary electrophoresis and capacitively coupled contactless conductivity detection(FASS-CE/C~4D).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 signifcantly 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-C~4D without derivatization.Due to its low sample consumption,high sensitivity(LODs:0.070–0.17 ng/mL),and acceptable recoveries(90–105%),this AuNPs-ME/FASS-CE-C~4D 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.3.Trace Analysis of Biological Thoils by Tween 20-AuNPs-ME/CE-C~4D methodIn this work,a Tween 20-AuNPs-ME/CE-C~4D combined method was established for the direct determination of the main biological thiols,GSH,Hcy and Cys in saliva,which fused the high purification and selective enrichment performance of Tween 20-AuNPs,the high separation efficiency of CE and the versatility of C~4D.The target analytes were selectively adsorbed on the surfaces of AuNPs by forming gold-sulfur bonds.Meanwhile,the detection sensitivity of the method(LODs:2.0-5.7 ng/mL)was further improved based on the synergistic enrichment effects of FASS and tween-20-AuNPs-ME,the enrichment factor reached 2083-3112 times,andacceptable recovery(96-101%)could be obtained.Under optimum conditions,GSH,Hcy and Cys could be well separated from the potential coexisting substances and then directly detected by CE-C~4D without derivatization.This method was expected to provide a simple,rapid and economical analytical method for the direct sensitive detection of biological thiols in saliva,and has potential applications in the early non-invasive diagnosis of related diseases.