under the supervision of

Prof. M. R. Islam

Dr. Sujit Kumar Ghosh 

Department of Chemistry Assam University Silchar-788011, Assam INDIA

by

Hirak Chatterjee

• Molecules accumulate at the interface between air and solvent.

• Reduces surface tension of the liquid.

• Shape of aggregates changes according to surfactant conc. of

the system.

• Based on the electrostatic interaction between dye & surfactant molecules.

• The following equilibrium occurs: L (aqueous phase, CL) ↔ SLN

(surfactant phase, CS) in L-S solution

• Optical detection method.

• Dye adsorption occur at miceller core.

• Dyes show different adsorption & emission spectra based on surfactant

concentration.

• Applicable for premiceller concentration of surfactants also.

• Premiceller self assembly of dye-surfactant systems can be elucidated.

Dye molecules

Surfactant molecules

Solvent molecules

• Cetylammonium bromide (CTAB)

• CMC=8×10-3 mol/dm3.

N Me3 BrH3C

• Flourescein isothiocyanate (FITC) Two sugar analogues of FITC

• Flourescein isothicyanate-Dextran40S

(Molecular weight =40000g/mol)

• Flourescein isothicyanate-Dextran2000S

(Molecular weight = 2000000g/mol).

450 500 550

0.00

0.04

0.08

0.12A

bsor

banc

e

Wavelength (nm)

0 M

10-6 M

10-5 M

10-4 M

10-3 M

10-2 M

10-1 M

[CTAB]

Absorption spectra of FITC (50 μM) at different CTAB concentration

.

500 525 550 575 6000

200

400

600

800

1000

Flu

ores

cenc

e In

tens

ity

Wavelength (nm)

0.50 nM 0.75 nm 1.0 nM 2.5 nM 5.0 nM 7.5 nM 10.0 nM 25.0 nM

[FITC]

Fluorescence spectra of FITC in aqueous solution at different concentration of the dye molecules

0 5 10 15 20 25

0

200

400

600

800

1000

Flu

ores

cenc

e In

tens

ity (

at 5

20 n

m)

[FITC] (nM)

R2 = 0.9909

Fluorescence intensity as a function of FITC concentration

Emission peak appeared in between the CTAB concentration range 1 to 10 mM

500 520 540 560 580 600

0

50

100

150W

avel

engt

h (n

m)

Wavelength (nm)

0 M

10-6 M

10-5 M

10-4 M

10-3 M

10-2 M

10-1 M

[CTAB]

500 525 550 575 6000

40

80

120F

luor

esce

nce

Inte

nsity

Wavelength (nm)

2 mM 3 mM 4 mM 5 mM 6 mM 7 mM 8 mM 9 mM 10 mM

[CTAB]

• The peak obtained at the minimum CTAB concentration of 3.0 mM.

• The emission maxima was obtained at 526 nm.

• Intensity increases linearly with the CTAB concentration.

1*10-3 2*10-3 3*10-3 4*10-3 5*10-3 6*10-3 7*10-3 8*10-3 9*10-3

-20

0

20

40

60

80

100

120

Inte

nsity

(at

526

nm

)

CTAB concentration (mol/dm3)

500 520 540 560 580 6000

10

20

30F

luo

resc

en

ce I

nte

nsi

ty

Wavelength (nm)

0.3 mM 0.4 mM 0.5 mM 0.6 mM 0.7 mM 0.8 mM 0.9 mM 1.0 mM

[CTAB]

The spectra obtained show the peak at the minimum CTAB

concentration of 0.4 mM.

Maximum intensity of the emission peak corresponding to 0.4mM

CTAB concentration was found at 520 nm.

Intensity increment with CTAB concentration occurs in a non-

linear fashion.

Change in ionic atmosphere & self quenching of probes may be

attributed as the cause for non-linearity.

500 520 540 560 580 6000

10

20

30

Flu

ore

scen

ce I

nten

sity

Wavelength (nm)

1 mM 2 mM 3 mM 4 mM 5 mM

[CTAB]

• FITC-Dextran 40S was diluted 10 times of primary concentration. It was diluted to 0.5 nM.

• Stokes’s shift appeared at CTAB concentration of 2.0 mM.

• Maximum intensity obtained at 526 nm.

• Intensity increased linearly with the increment of CTAB concentration.

1*10-3 2*10-3 3*10-3 4*10-3 5*10-3

-5

0

5

10

15

20

25

30

Inte

nsi

ty [at 526 n

m]

CTAB concentration (mol/dm3)

500 520 540 560 580 6000

10

20

30

Flu

ores

cenc

e In

tens

ity

Wavelength (nm)

2 3 4 5 6

[CTAB]

The spectra obtained show the peak at the minimum CTAB concentration

of 3 μM.

Maximum intensity of the emission peak corresponding to 3 μM CTAB

concentration was found at 515 nm.

Intensity increment with CTAB concentration occurs in a non-linear

fashion.

Change in ionic atmosphere & self quenching of probes may be attributed

as the cause for non-linearity

500 525 550 575 6000

10

20

30

40F

luor

esce

nce

Inte

nsity

Wavelength (nm)

1 mM 2 mM 3 mM 4 mM 5 mM 6 mM 7 mM 8 mM

[CTAB]

• Involves dilution of 5nM FITC-Dextran(2000S) to thousand times,

i. e., 5 pM solution was taken.

• Stokes’s shift appeared at CTAB concentration of 2.0 mM.

• Maximum intensity obtained at 546 nm.

• Intensity increased linearly with the increment of CTAB concentration.

0 2 4 6 8 10

0

5

10

15

20

25

30

35

Inte

nsi

ty [at 546 n

m]

CTAB concentration (mM)

Solution System Variable

ComponentIntensity

Incrementλem λex

FITC +Water FITC concentration Linear 516 nm 490 nm

FITC + CTAB CTAB concentration

Linear 526 nm 490 nm

FITC D 40 S + CTABCTAB

concentrationNon-linear 523 nm 490 nm

FITC D 40 S + CTAB (BACK)

CTAB concentration

Linear 526 nm 490 nm

FITC D 2000S + CTABCTAB

concentrationNon-linear 515 nm 490 nm

FITC D 2000 S+ CTAB (BACK )

CTAB concentration

Linear 546 nm 490 nm

The minimum concentration at which CTAB & FITC forms

premiceller self-assembly was determined by spectrometric method ,and

effect of sugar bulk on the self assembly was determined by correlated

studies.

The dye-surfactant interaction below the CMC of CTAB has been

characterised by UV-vis and fluorescence emission spectroscopic studies.

This study has explored several features of miceller chemistry in one

hand and versatile behavior of interaction with the surfactant used with

a fluorescence probe with increasing its bulkiness in another.

1. Rosen, M. J. Surfactants and Interfacial phenomena ; 3rd edition;Wiley-Interscience (2004).2. Gohain, B.; Dutta,R. K., Premicellar and micelle formation behavior of dye-surfactant ion-pairs In aqueous solutions: Deprotonation of dye in ion pair micelles, J. Colloid Interface Sci. 2008, 323,395-402.3.Gao, H. W.; Zhou, D. Y. Langmuir Aggregation of Fluorescein Isothiocyanate (FITC) on Cetyl Trimethylammonium Bromide (CTAB) and Application to Determination of Anionic Detergent in Sewage, Bull. Korean Chem . Soc. 2002, 23, 29-34.4. Diaz Garcia, M. E.; Sanz-Medel, A. Dye-surfactant interactions: a review, Talanta 1986, 33, 255-264. 5. Acharya, S.; Rebery B. Fluorescence Spectrometric Study of Eosin Yellow Dye-Surfactant Interactions, Arabian J. Chem. 2009, 2, 11-19.6. Lakowicz, J. R. Principles of Fluorescence Spectroscopy: Plenum Press: NewYork(1983).7. TdB Consultancy AB, www.tdbcons.se, Version: FD010AA, Date: 12/2010.8. Garćia-verdugo, I., Śanchez-Barbero, F., Soldau, K., Tobias, P. K.; Casals,C. Interaction of SP-A (surfactant protein A) with bacterial rough lipopolysaccharide (Re-LPS), and effects of SP-A on the binding of Re-LPS to CD14 and LPS-binding protein, Biochem. J. 2005, 391, 115-124.9. Determana, A. S.; Trewyn, B.G.; Lin, V. S. -Y.; Hamilton, M. N-, Narasimhana, B., Encapsulation, stabilization, and release of BSA-FITC from poly anhydride microspheres, J. Controlled Release 2004,100, 97-109. 10. Garcia-Verdugo, I.; Tanfin, Z.; Dallot, E ; Leroy, M. J.; Breuiller-Fouché, M. Surfactant Protein A Signaling Pathways in Human Uterine Smooth Muscle Cells, Biol. Reproduct. 2008, 79, 348-355.

HOD, Chemistry

All Faculty Members

Non-Teaching Staff Members

Research Scholars

4th and 3rd Semester Students

Spervisor:Prof.M.R.Islam

Co-Supervisor: Dr. Sujit Kumar Ghosh