- Discover essay samples

Fluorescence study of dyes

4.9 of 5.0 (19 reviews)

647 words

Fluorescence study of dyes Page 1
Fluorescence study of dyes Page 2
Fluorescence study of dyes Page 3
Fluorescence study of dyes Page 4
Fluorescence study of dyes Page 5
Fluorescence study of dyes Page 6
The above thumbnails are of reduced quality. To view the work in full quality, click download.

Fluorescence study of dyes

Fluorescence Study of the

Kinetics of Energy

Transfer Between Dyes

1. Introduction

Coumarin 1 and Sodium fluorescein are two dyes which absorb and emit light in the visible region. By using a spectrophotometer we are recording an absorption spectrum and then determining the molar decadic absorption coefficients, which will be used later to interpret and analyse the fluorescence spectra.

For fluorescence spectra, there are two kinds, the excitation and the emission spectrum.

The excitation spectrum is obtained by measuring the intensity of the emission as the excitation wavelength is altered by scanning a monochromator. The emission spectrum is obtained by measuring the emission intensity as a function of wavelength for excitation at a fixed wavelength.

An absorption spectrum and an excitation spectrum are by their nature actually equivalent.

The two dyes exhibit energy transfer properties. The donor is coumarin and the acceptor the fluorescein. When the donor is excited, it is naturally decaying to the ground state. However in presence of an acceptor, this process is enhanced trough energy transfer. We will distinguish between collisional energy transfer and dipole-dipole transfer. From here we will try to determine the quenching constant and the distance at which decay and energy transfer are equally probable, as well as prove that Stern-Volmer's law and F'rster's theory are obeyed.

2. Results

2.1. Electronic Absorption Spectra

We made up stock solutions for both salts and diluted them down to use in the UV/vis spectrometer.

Coumarin 1

C = 8 x10-5 mol dm -3

We obtained a spectrum with a maximum at 376.5nm at an absorbance of 1.4573, using Beer-Lambert's law, we deduced the molar decadic absorption coefficients.

Sodium fluorescein

C = 2.425 x10-5 mol dm -3

Here max was 500.5 nm at an absorbance of 2.0922

Summary of the results obtained.


max (nm)

max (m2 mol-1)

(m2 mol-1)

' (m2 mol-1)

D (Coumarin)


1.82 x 109


1.25 x 106

A (Fluorescein)


5.17 x 107

1.41 x 106

8 x 106

2.2. Fluorimetry

a) Perylene standard

/nm I

Emission Spectrum 438 4.063 EX = 434nm

467 2.620

Excitation Spectrum 410 2.755 EX = 438nm

437 4.208

These are the values for the maxima in both spectrum, for the graphs, see attached sheet.

b) Coumarin 1 C = 4 x10-6 mol dm -3

/nm I

Emission Spectrum 374 1.050 EX = 377nm

443 4.081

Excitation Spectrum 373 4.156 EX = 443 nm

446 1.026

b) Sodium fluorescein C = 1.212 x10-6 mol dm -3

/nm I

Emission Spectrum 516 7.453 EX = 501nm

Excitation Spectrum 501 7.516 EX = 516 nm

On the graphs of the standard and the two dyes, we can nicely see that the excitation and emission spectra are mirror images of each other overlaid.

The excitation wavelength in one is the highest emitting one in the other.

2.3. Energy Transfer

Stern-Volmer equation

0 / = 1 + K [A] (1)

with 0 / being the ratio of quantum yield and

K being the Stern-Volmer ...

You are currently seeing 50% of this paper.

You're seeing 647 words of 1294.

Keywords: fluorescence studies of dyes, which dye is used in fluorescence microscopy, what is the process of fluorescence, what is fluorescence in chemistry, what is fluorescence analysis

Similar essays

EPA urges tough rules on arsenic

Arsenic in Water Person 1- For our table topic we are doing '.' The Environmental Protection agency has concluded that it must adopt a new standard for the amount of arsenic allowed in the nation's drinking water that is at least as though as the one proposed by the Clinton administration, officials said yesterday. Christie Whitman recom...

171 reviews
Comparison of prokaryotic and eukaryotic cells

Comparison of Plant and Animal Cells Introduction Eukaryotic cells are very complex; there are many organelles, each serving a distinct function, present in eukaryotic cells. We can divide the eukaryotic group of cells in to two main groups, according to the presence of these membrane bound organelles, and the structural differences a...

143 reviews
How eagles live

How the Eagles Live My purpose of this paper is to explain the different types of eagles and how they live. The bald eagle has the scientific name of haliaetus leucocephalus and is named for its white feathers that cover its head and neck. It is from the family accipitridae. An adult bald eagle is usually 40 inches long, and...

185 reviews
A Fabulous Analysis of the Flamboyantly Gay

Reaching the Breaking Point Have you ever heard a heterosexual talking about a homosexual, saying things like 'Jake would be a cool guy if he wasn't such a flamer' or 'I don't have a problem with gays, but I just want to know why he has to act so gay'? Perhaps you have even said something similar yourself. Unfortunately the catalyst of t...

22 reviews

: The True Story of a Lone Genius Who Solved the Greatest Scientific Problem of His Time is written by Dava Sobel. The book is called because it is about a clock maker who was able to determine longitude. Determining longitude was the superlative scientific question in the eighteenth century that Galileo and Newton were not able to resolve....

108 reviews
Corrosion and Rusting

Introduction Some people may be annoyed by their car ?wearing out?. Kids may have trouble with rust forming on their bicycles. One may think how to prevent rusting, but do one knows what is happening when a metal corrode? ?Corrosion is defined as the involuntary destruction of substances such as metals and mineral building...

145 reviews
Chlamydial infection

Chlamydia is the most common bacterial sexually transmitted disease in the United States today. The U.S. Centers for Disease Control and Prevention estimates that more than 4 million new cases occur each year. The highest rates of chlamydial infection are in 15 to 19-year old adolescents regardless of demographics or location. Pelvic inflam...

97 reviews
Global warming 2

- Global Warming I have chosen to speak about Global warming because it is a major scientific issue in the media. Problems facing the environment today are vast and diverse. Destruction of the world's rain forests, the depletion of the ozone layer, air pollution, water pollution, chemical pollution and global warming are just some of...

155 reviews
Transmission of Aids

INTRODUCTION As we all know, AIDS (Acquired Immune Deficiency Syndrome) is a fatal infection caused by the Human Immunodeficiency Virus (HIV). The virus attacks the body's immune system and, over a period of time, destroys it. This disables the body's ability to fight off infections by other germs and the growth of cancers, eventually resulti...

209 reviews
Chromosome probes at the university of toronto

Chromosome Probes at the University of Toronto Uploaded: November 29, 1986. Sensitive chromosome probes recently discovered by a University of Toronto geneticist will make it easier to detect certain types of genetic and prenatal diseases, as well as being used to determine paternity and provide forensic evidence in criminal cases. Probe...

16 reviews
Clouds Formations

Cloud formations have always been observed by people, many centuries before our time. People were always fond of clouds. They always wondered why some clouds were dark and others were white and fluffy, and why some clouds are so up high and others were so low that they looked reachable by the human hands. The most recent classi...

132 reviews
The Jovian Planets

Far beyond Earth in the solar nebula lies an ice belt and beyond that lay the four Jovian planets. They are Jupiter, Saturn, Uranus and Neptune. Jovian means "Jupiter- like" in which the rest of the jovian planets do coincide with the name. Uranus Neptune and Saturn, all carry the same traits as Jupiter. The jovian planets are large gas...

32 reviews
Transplants and Diabetes

Three Toronto scientists have developed an organ transplant procedure that could, among its many benefits, reverse diabetes. The procedure was developed by Bernard Leibel, Julio Martin and Walter Zingg at the University of Toronto and the Hospital for Sick Children. The story of their work began in 1978, when they delved into...

180 reviews
Biological and chemical weapons

The Development and Control of Chemical and Biological Warfare The year, 600 BC. Solon, the legislator of the Athenians, contaminated the River Pleisthenes with hellebores (skunk cabbage) to give the defenders of Kirrha violent diarrhea leading to their defeat. This is the first recorded use of plants as a source of chemicals for warfare....

2 reviews
Atsisiųsti šį darbą