Electronic Supplementary Material

Enhanced chemiluminescenceof the luminol–KIO4 system byZnS nanoparticles

Shifeng Li[*], Xiangzi Li, Yanqi Zhang, Fei Huang, Fenfen Wang, Xianwen Wei[*]

College of Chemistry and Materials Science, Anhui Key Laboratory of Functional Molecular Solids, Anhui Key Laboratory of Molecule-based Materials, Anhui Normal University, Wuhu 241000, P. R. China

Preparation of ZnS Nanoparticles

Functionalized ZnS nanoparticles were synthesizedaccording to refs 34 and 35 with little modification. Briefly, the synthesis of the colloidal solutionswas carried out in a 250 mL three-neckedround bottomed flask with a pH electrode. Deionized water (100 mL) werepurged with nitrogen for 30 min, 1.25 mmol ZnCl2 and 3mmol mercaptoethanol (or 3-mercaptopionic acid)were added to the flask, and the pH was adjusted to 10.2 (or 12.16) using 1.0 mol L–1 NaOH. Under vigorous stirring,sulfureted sodium solution wasadded drop by drop. For the purified ZnS NPs samples, the free Zn2+, Cl–, S2– and ME (or MPA) were removed via dialysis for two days in 0.01mol L–1NaOH solution according to the procedure inliterature [12]. Dialyzed sample was further mixed with ethanol and stirred thoroughly. The solution was centrifuged to obtain the precipitate, then dried in a vacuum to obtain a fine white powder for XRD analyse.

Enhancement of Luminol CL

Fig. S1 Kinetic characteristics of the CL system, a: Luminol–KIO4 CL system, b: luminol–KIO4MP/ZnS NPs, c: luminol–KIO4MPA/ZnS NPs, d: c+ofloxacin, e: c+ciprofloxacin, f: c+lemofloxacin, g: c+fleroxacin, h: c+levofloxacin, i: c+norfloxacin.

Optimization of the Reaction Conditions

The effect of the concentration of luminol on the increased CL intensity was examined in the range of 7.5×10–6 to 1.0×10–4 mol L–1. The optimum CL intensity was obtained with1.0×10–5 mol L–1 luminol(Fig.S2-A). It is well known that the CL of the luminol–KIO4 system occurs in alkaline mediums.The effect of NaOH concentration on the increased CL intensitywas examined from 0.006mol L–1 to 0.06mol L–1 (Fig. S2-B). Maximum increased CL intensity obtained when the concentrationof NaOH was fed at 0.02mol L–1. The effect of KIO4 concentration was tested in the range 1.010–51.0×10–4 mol L–1(Fig. S2-C), the result showed that the CL intensity increased with increasing KIO4 concentration in the range of 1.0×10–52.0×10–5 mol L–1 and then decreased when the concentration of KIO4was higher than 2.0×10–5 mol L–1. The influence of the media of KIO4 solution on the increased CL reaction was also investigated(Fig. S2-D).The relative CL intensityreached the maximum and the highest ratio of the peak height of CL signal to noise(S/N) was obtainedatKOH media of 0.04 mol L–1. The effect of flow rate on the CL reaction was also examined. The relative CL intensity continued to increase with increasing the flow rate from 1.5 to 5.0 mlmin–1. But a high flow rate might lead to the irreproducibility and excess consume of the reagents. Finally, 3.0 mlmin–1 of flow rate was chosen by considering the sensitivity, reagents consumption and reproducibility.

Fig. S2 Effects of reaction conditions on the CL intensity, (A) luminol concentration, (B) NaOH medium1, (C) KIO4 concentration, (D) KOH medium

Table S1Determination of lemofloxacin in pharmaceutical capsules (n=9)

Sample / Labeled value
(g mL–1) / Lemofloxacin
added (g mL–1) / Found (g mL–1) / Recovery (%) / R.S.D. (%)
1
2
3
4
5 / 2.510-7 / 0
1.010-7
2.010-7
3.010-7
4.010-7 / 2.6310-7
3.4210-7
4.6710-8
5.7510-7
6.5910-7 / −
97.7
103.8
104.5
101.4 / 1.5
2.1
2.8
3.1
2.3

It can be seen that there are no significant differences between labeled contents in pharmaceutical formulation samples and those obtained by the proposed method. From the recovery of 97.7–104.5% obtained, the feasibility of the development method for real sample analysis can be confirmed.

1

[*]Corresponding author. Tel.: +86 553 3937138; fax: +86 553 3869303.

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