Colorimetric detection nd seprtion of chirl tyrosine sed on N-cetyl-L-cysteine modified gold nnoprticles Hiyn Su, Qiuling Zheng nd Hiing Li* Key Lortory of Pesticide nd Chemicl Biology (CCNU), Ministry of Eduction, College of Chemistry, Centrl Chin Norml University, Wuhn 430079 (P. R. Chin), E-mil: lhing@mil.ccnu.edu.cn Mterils nd regents All chemicls used were of nlyticl grde or of the highest purity ville. HAuCl4.3H2 ws purchsed from Shng Hi Chemicl Regent C., LTD., Chin. Sodium orohydride (NBH4, 98%) ws purchsed from Tinjin Chemicl Regent Plnt, Chin. N-cetyl-L-Cysteine ws purchsed from Shnghi Bio Science & Technology. Co., LTD, Chin. L-Tyrosine, D-Tyrosine nd rcemic Tyrosine were purchsed from Shnghi Source poly Biotechnology Co., Ltd, Chin. Wter used in this experiment ws purified y distilltion of deionized wter. Chrcteriztion The morphology nd size of Au NPs, NALC-Au NPs nd fter tretment with Tyr were chrcterized y trnsmission electron microscopy (TEM) y Philips TecniG2 TEM using n ccelerting voltge of 200kV. The UV-visile (UV-vis) sorption spectr were tken t room temperture on UV-2501 spectrophotometer (SHIMADZU CRPRATIN) with vrile 1
wvelength etween 200 nd 1000 nm using glss cuvette with cm opticl pth. The infrred (IR) spectr were collected on Thermo Nicolet NEXUS IR spectrometer in the wvenumer rnge 400-4000cm -1 t resolution of 4 cm -1. The smples were prepred in the form of pellets together with KBr. Synthesis of NALC-Au NPs 100 ml queous solution of HAuCl4. 3H2 (89 mg/ml) nd ml 2 10-3 queous solution of N-cetyl-L-Cysteine were mixed stirring for 20 min, then ml of 10-3 M fresh sodium orohydride ws dded nd otined N-cetyl-L-Cysteine modified Au NPs (NALC-Au NPs). L-Tyr chirl recognition experiments y NALC-Au NPs ml D- or L-tyrosine solution ws respectively dded in 1.5 ml NALC-Au solution nd ultrviolet-visile spectroscopy were determined. Then centrifuge for 5 min in the speed 12000 r/min nd tke out the cler liquid to show color experiment y ninhydrin Tyr enntiomeric seprtion experiments y NALC-Au NPs ml rcemic tyrosine solution ws dded in 1.5 ml NALC-Au solution nd ultrvioletvisile spectroscopy were determined. Then centrifuge for 5 min in the speed 12000 r/min nd tke out the cler liquid to show color experiment y ninhydrin. Determintion of Tyr content of the solution y ninhydrin efore nd fter the seprtion Tow copies of 1.8 ml Tyr solution were respectively dded to ml 5 10-2 M ninhydrin solution efore nd fter the seprtion, oiling for 10 min nd cooling to room temperture, the UV - visile sorption spectroscopy were determined. 2
Supplementry Figures HAuCl 4 HS H 3 C HN NBH4 H - H 3 C HN S S Au NH CH 3 S - - HN CH 3 Scheme S1 Synthesis of NALC-Au NPs. 100 100 80 80 %T 60 %T 60 40 40 C=: 1637 cm-1 20 20 0 3500 3000 2500 2000 1500 1000 500 Wvenumer (cm -1 ) 0 3500 3000 2500 2000 1500 1000 500 Wvenumer(cm -1 ) Fig. S1 The FT-IR spectrum of unmodified Au NPs () nd NALC-Au NPs (). 3
35 30 percentge(%) 25 20 15 10 5 0 5 6 7 8 9 10 11 12 13 Size (nm) Fig. S2 The size distriution of NALC-Au NPs. 100 prticles re mesured to get the size distriution. According to the size distriution, the dimeter of NALC-Au NPs is out 7 nm. 0.6 A 522 0 2 4 6 8 10 dy(d) Fig. S3 UV-vis sorption spectr of NALC-Au NPs ffected y dy t 522 nm. 4
0.6 A 522 0 2 4 6 8 10 12 14 Fig. S4 UV-vis sorption spectr of NALC-Au NPs ffected y ph t 522 nm. ph Fig. S5 TEM imges of NALC-Au NPs efore () nd fter () tretment with rcemic tyrosine. 5
Asornce 0.75 0 5 250 μm L-Tyr 250 μm L-Tyr (fter seprtion) 188 μm L-Tyr 188 μm L-Tyr (fter seprtion) A 570 Before seprtion After seprtion 0 500 600 700 800 Wvelength(nm) 250 μm L-Tyr 188 μm L-Tyr Fig. S6 The UV-vis sorption spectr of the systems tht Ninhydrin solution rected with L-Tyr solutions (250 nd 188 μm, respectively) efore nd fter seprtion () nd the corresponding sorption vlue t 570 nm (). Asornce 0.75 0 5 250 250 fter seprtion 188 188 fter seprtion A 570 Before seprtion After seprtion 0 600 800 Wvelength (nm) 250 188 Fig. S7 The UV-vis sorption spectr of the systems tht Ninhydrin solutions rected with rcemic Tyr solution (500 nd 188 μm, respectively) efore nd fter seprtion () nd the corresponding sorption vlue t 570 nm (). 6
B D-Tyr L-Tyr A L-Tyr D-Tyr Fig. S8 Chirl HPLC system used for confirming the seprtion of rcemic Tyr mixture, (A) efore ggregtion with the nnoprticles, the rtion of [D-Tyr] to [L-Tyr] concentrtion ws out. (B) fter ggregtion, the rtion incresed to 0.73, which could e seen from the integrtion re in the ove grph. References [1] M. M.Mye,; L. Hn,; N. N. Kriuki,; N. K. Ly,; W. B. Chn,; J. Luo,; C. J. Zhong, Anl. Chim. Act., 2003, 496, 17-27. 7