Determination of Cr(Ⅵ) by Ratiometric and Visual Fluorescence Method Based on Formaldehyde Functionalized Polyethyleneimine-rhodamine B Hydrazide System†

doi:10.7503/cjcu20150962

Abstract

Abstract:

Formaldehyde functionalized fluorescent polyethyleneimine(FPEI) were prepared via microwave-assisted synthesis. In H₂SO₄ media, the amine groups on the FPEI surface would be protonated and adsorb Cr(Ⅵ) via electrostatic attraction, and the fluorescence intensity of the FPEI at 480 nm decreased accordingly. At the same time, potassium dichromate can oxidize rhodamine B hydrazide(RBH) to rhodamine B in acidic aqueous conditions, resulting in recovery of rhodamine B fluorescence and absorbance, the absorption bands of which ranged from 250 nm to 600 nm, fully covering the emission and excitation bands of FPEI. Thus, the inner filter effect occurring in FPEI/RBH system led to further decrease of the fluorescence intensity of the FPEI. The fluorescence change ratio(F₅₈₀/F₄₈₀) between the fluorescence intensity of rhodamine B at 580 nm and that of FPEI at 480 nm has a good linear correlation with the concentration of Cr(Ⅵ), and a noticeable blue to orange color change was detected under an ultraviolet lamp if Cr(Ⅵ) solution was mixed with the FPEI/RBH. Based on the phenomena, a novel rapid ratiometric and visual fluorescence method for determination of Cr(Ⅵ) was developed. Under optimal conditions, the ratio fluorescence intensity F₅₈₀/F₄₈₀ increased linearly with the concentration of Cr(Ⅵ) ranging from 0.1 μmol/L to 3.6 μmol/L with a detection limit of 12 nmol/L. In addition, the change of fluorescence color was related to the concentration of Cr(Ⅵ) in the range of 0.4—2.8 μmol/L. The proposed method, being highly selective, simple and rapid, could be applied to determine the concentration of Cr(Ⅵ) samples with recovery of 90%—109%.

Key words: Formaldehyde functionalized polyethyleneimine, Rhodamine B hydrazide, Ratiometric fluorescence, Visual fluorescence, Cr(Ⅵ)

CLC Number:

O657.3

TrendMD:

YANG Chuanxiao, YU Mengwen, SONG Duoduo, SUN Xiangying. Determination of Cr(Ⅵ) by Ratiometric and Visual Fluorescence Method Based on Formaldehyde Functionalized Polyethyleneimine-rhodamine B Hydrazide System^†[J]. Chem. J. Chinese Universities, 2016, 37(5): 852.

Figures/Tables 15

Scheme 1 Reaction between FPEI-RBH and Cr(Ⅵ)

Fig.1 Fluorescence spectra and fluorescence change(inset) of FPEI-RBH in the absence(A) and presence(B) of Cr(Ⅵ)

Fig.2 TEM image of FPEI(A), UV-Vis absorption and fluorescence spectra of FPEI(B) and infrared spectra of PEI(a) and FPEI(b)(C)

Fig.3 Ratiometric fluorescence emission(A) and UV-Vis absorption spectra(B) of the reaction between FPEI-RBH and Cr(Ⅵ)Inset of (A): fluorescent change under 365 nm light excitation.

Fig.4 Fluorescence emission spectra of the reaction between FPEI, RBH and Cr(Ⅵ), respectivelya. FPEI; cRBH/(μmol·L-1): b. 0, c. 2.5, d. 5.0, e. 7.5, f. 10. Cr(Ⅵ): 2.0 μmol/L; H2SO4: 2.0 mmol/L; λex=360 nm.

Fig.5 Fluorescence excitation(a) and emission(b) spectra of FPEI and UV-Vis absorption spectrum(c) of RB(A) and effect of the inner filter on the fluorescence intensity of FPEI(B)

Fig.6 Effect of H2SO4 concentration on the reaction between FPEI-RBH(A) and Cr(Ⅵ)(B)

Table 1 Effect of H2SO4 concentration on analytical parameters for the determination of Cr(Ⅵ)

$c H 2 S O 4$ /(mmol·L^-1)	Linear range/(μmol·L^-1)	R²	Linear regression equation
0.5	0.0—2.0	0.9826	F₅₈₀/F₄₈₀=0.46c+0.27
1.0	0.0—3.2	0.9984	F₅₈₀/F₄₈₀=0.84c+0.19
2.0	0.0—3.6	0.9948	F₅₈₀/F₄₈₀=1.10c+0.01
4.0	0.0—2.0	0.9814	F₅₈₀/F₄₈₀=0.95c+0.10
4.0	2.0—3.6	0.9906	F₅₈₀/F₄₈₀=1.89c-1.85
8.0	0.0—2.0	0.9923	F₅₈₀/F₄₈₀=0.84c+0.16
8.0	2.0—3.6	0.9912	F₅₈₀/F₄₈₀=2.13c-2.48
12.0	0.0—2.0	0.9795	F₅₈₀/F₄₈₀=0.95c+0.09
12.0	2.0—3.6	0.9875	F₅₈₀/F₄₈₀=2.34c-3.09
16.0	0.0—1.6	0.9829	F₅₈₀/F₄₈₀=0.98c+0.12
16.0	1.6—3.6	0.9767	F₅₈₀/F₄₈₀=1.92c-1.32

Table 1 Effect of H2SO4 concentration on analytical parameters for the determination of Cr(Ⅵ)

$c H 2 S O 4$ /(mmol·L^-1)	Linear range/(μmol·L^-1)	R²	Linear regression equation
0.5	0.0—2.0	0.9826	F₅₈₀/F₄₈₀=0.46c+0.27
1.0	0.0—3.2	0.9984	F₅₈₀/F₄₈₀=0.84c+0.19
2.0	0.0—3.6	0.9948	F₅₈₀/F₄₈₀=1.10c+0.01
4.0	0.0—2.0	0.9814	F₅₈₀/F₄₈₀=0.95c+0.10
4.0	2.0—3.6	0.9906	F₅₈₀/F₄₈₀=1.89c-1.85
8.0	0.0—2.0	0.9923	F₅₈₀/F₄₈₀=0.84c+0.16
8.0	2.0—3.6	0.9912	F₅₈₀/F₄₈₀=2.13c-2.48
12.0	0.0—2.0	0.9795	F₅₈₀/F₄₈₀=0.95c+0.09
12.0	2.0—3.6	0.9875	F₅₈₀/F₄₈₀=2.34c-3.09
16.0	0.0—1.6	0.9829	F₅₈₀/F₄₈₀=0.98c+0.12
16.0	1.6—3.6	0.9767	F₅₈₀/F₄₈₀=1.92c-1.32

Fig.7 Effects of RBH concentration(A) and FPEI amount(B) on the reaction between FPEI-RBH and Cr(Ⅵ)

Fig.8 Effect of HCHO concentration on the reaction between FPEI-RBH and Cr(Ⅵ)Inset: effect of HCHO amount on the fluorescent intensity of FPEI.

Fig.9 Infrared spectra of FPEI with different microwave powersInset: effect of microwave power on A1580/A1662.

Fig.10 Tolerance of substance on the determination of Cr(Ⅵ)(A) a. Blank; b. Cr(Ⅵ); c. Ca2+; d. K+; e. Na+; f. Mg2+; g. Cu2+; h. Fe2+; i. Fe3+; j. Pb2+; k. Zn2+; l. Ag+; m. Mn2+; n. Hg2+; o. Cd2+; p. Al3+; q. Cr3+; r. Ni2+; s. Co2+. (B) a. CTAB; b. SLS; c. SDS; d. STPP; e. F-; f. Br-; g. I-; h. PO43-; i. CO32-; j. H2O2; k. NO3-; l. NO2-; m. MnO4-; n. ClO3-; o. IO4-; p. ClO-; q. S2O32-; r. S2-; s. SO32-.

Fig.11 Plots of fluorescence intensity at 580 nm and F580/F480 via the concentrations of Cr(Ⅵ)Inset: Visual detection of Cr(Ⅵ) with different concentrations.

Table 2 Analytical parameters for the determination of Cr(Ⅵ)

Method	Linear regression equation	R²	Linear range/(μmol·L^-1)	LOD/(nmol·L^-1)
Ratiometric fluorescence	F₅₈₀/F₄₈₀=0.98c+0.11	0.9933	0.1—3.6	12
Single fluorescence	F₅₈₀=126.45c+58.33	0.9909	0.2—2.0	25

Table 3 Results for the determination of Cr(Ⅵ) in water samples

Sample	Content/(μmol·L^-1)	c_Cr(Ⅵ)/(μmol·L^-1)		Recovery(%)
Sample	Content/(μmol·L^-1)	Added		Found
1	0	0.4	0.41	103.3
2	0	0.8	0.72	90.0
3	0.11	1.2	1.42	109.1

References 22

[1]	Barrera-Díaz C. E., Lugo-Lugo V., Bilyeu B., J. Hazard.Mater., 2012, 223, 1—12
[2]	Li L. L., Fan L. L., Sun M., Qiu H. M., Li X. J., Duan H. M., Luo C. N., Colloids Surf.Biointerfaces, 2013, 107, 76—83
[3]	Fang J., Gu Z. M., Gang D. C., Liu C. X., Ilton E. S., Deng B. L., Environ. Sci.Technol., 2007, 41, 4748—4753
[4]	Ma H. L., Zhang Y., Hu Q., Yan D., Yu Z., Zhai M., J. Mater.Chem., 2012, 22, 5914—5916
[5]	Wei Y. X., Tu W. X., Chem. J. Chinese Universities,2014, 35(11), 2397—2402
	(魏英祥, 涂伟霞. 高等学校化学学报, 2014, 35(11), 2397—2402)
[6]	Vacchina V., de la Calle I., Séby F., Anal. Bioanal.Chem., 2015, 407(13), 3831—3839
[7]	Wang X., Xing Y. N., Chen Z. Y., Huo J. Y., Chen L. Q., Chinese J. AnalChem., 2013, 41(1), 123—127
	(王欣, 幸苑娜, 陈泽勇, 霍巨垣, 陈丽琼. 分析化学, 2013, 41(1), 123—127)
[8]	Liu C., He C., Xie T., Xie T. P., Yang J., Fullerenes Nanotubes and CarbonNanostructures, 2015, 23(2), 125—130
[9]	Wei J., Guo Z., Chen X., Han D. D., Wang X. K., Huang X. J., Anal.Chem., 2015, 87(3), 1991—1998
[10]	Ji W., Wang Y., Tanabe I., Han X. X., Zhao B., Ozaki Y., Chem.Sci., 2015, 6(1), 342—348
[11]	Liu S. P., Liu Q., Liu Z. F., Li M., Huang C. Z., Anal. Chim.Acta, 1999, 379(1), 53—61
[12]	Sereshti H., Farahani M. V., Baghdadi M., Talanta, 2016, 146, 662—669
[13]	El-Shahawi M. S., Al-Saidi H. M., Bashammakh A. S., Al-Sibaai A. A., Abdelfadeel M. A., Talanta, 2011, 84(1), 175—179
[14]	Dalavi D. K., Bhopate D. P., Bagawan A. S., Gore A. H., Desai N. K., Kamble A. A., Mahajan P. G., Kolekar G. B., Patil S. R., Anal.Methods, 2014, 6(17), 6948—6955
[15]	Liu S. H., Lu F., Zhu J. J., Chem.Commun., 2011, 47, 2661—2663
[16]	Zheng M., Xie Z. G., Qu D., Li D., Du P., Jing X. B., Sun Z. C., ACS Appl. Mater.Interfaces, 2013, 5(24), 13242—13247
[17]	Xiang Y., Mei L., Li N., Tong A. J., Anal. Chim.Acta, 2007, 581, 132—136
[18]	Zheng A. F., Chen J. L., Wu G. H., Wu G. L., Zhang Y. G., Wei H. P., Spectrochim. Acta PartA, 2009, 74, 265—270
[19]	Ye C. L., Wang X. M., Fan J., Feng S. L., Spectrosc. Spect.Anal., 2006, 26, 1294—1297
	(叶存玲, 王新明, 樊静, 冯素玲. 光谱学与光谱分析, 2006, 26, 1294—1297
[20]	Sun X. F., Ma Y., Liu X. W., Wang S. G., Gao B. Y., Li X. M., WaterRes., 2010, 44, 2517—2524
[21]	Deng S., Ting Y. P., Environ. Sci.Technol., 2005, 39(21), 8490—8496
[22]	Larraza I., López-Gónzalez M., Corrales T., Marcelo G., J. Colloid Interface Sci., 2012, 385(1), 24—33