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Using Raman Spectroscopy to

investigate the ackee (BlighiaSapida) seed for Hypoglycin and

other chemicals.

Author: T. Strachan

Supervisor: r. !. "d#ard

Author $nformation

Name: Theodore S. Strachan

ID Number: 620033391

Major: Medical Ph!ic!

"uthor Note

 Thi! re#ort $a! #re#ared %or the cour!e Ph!2200 Practice! in

Med. Ph!ic! 1& 'ni(er!it o% the )e!t Indie! Mona& Science *

 Technolo+ ,acult- Ph!ic! De#artment

Date o% Submi!!ion: "#ril 2 201/

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Hi story of Raman Spectroscopy

Raman spectroscopy was first proposed in1923 by Alfred Smekal, it was based on the idea of 

the inelastic scattering of light[2,3! "t was later pro#ed and #erified by $% Raman and

&rishna in 192'[2,3(1! He recei#ed the noble pri)e later in 193* for this work[2,3(2! Raman

spectroscopy has since flo+rished with ad#ancements in tiss+e, cell and diseases st+dy

especially considering its ad#antages against the in vivo1 fl+orescence techni-+es ![. Some

of these ad#ancements incl+de the +se near(infrared /o+rier transform 0"R(/2 in the

regions of 04'*nm(9**nm and more recently $$50charged(co+ple de#ice systems allow

faster scan times![.(1

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Abstract

he problem that we are faced with is obtaining a Raman spectra that can be +tili)ed to

determine chemicals in o+r sample of the seed of the 6lighia Sapida 1 0ackee! ests ha#e been

done on the ackee seed prior to this research p+blication [1 b+t ne#er before with the +se of an

ad#anced Raman system! 7hat this research seeks to in#estigate is if we do ha#e Raman signals

can we discern a chemical s+ch as hypoglycin from the spectra and if not what does the spectra

indicate! he e8periment was done on se#eral ackees and from the spectra chemicals were

disco#ered b+t nothing concrete: that depicted the presence of Hypoglycin!

1. In vivo stands for invasive studies of biological samples(living samples)2. The Fourier transformation is named after Joseph Fourier which made a transfer between spatial time and 

 frequenc possible. It has man applications in phsics and engineering.

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"ntrod+ction

Raman spectroscopy is a +sef+l tool for +s to e8amine the nat+re of any small s+bstance or

ob;ect!

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Raman Spectroscopy bases its technology on the scattering of light! A molec+le is able to

 be e8cited if eno+gh energy is fire onto it, when light photons are scattered off of it they

do so with a wa#elength and fre-+ency [3,. ! Cost of the light scattered will contain thesame amo+nt of energy and wa#elength as the incident light so+rce this is Rayleigh

scattered light a small amo+nt howe#er 01 in 1*4 of the scattered will do so with a

different fre-+ency and wa#elength 0often less! he process that leads to this is termedRaman Scattering! his can occ+r with a change in #ibrational rotational or electrical

energies [2,3,.!!! 7hen light is elastically scattered it is termed Rayleigh1 scattering! Any

inelastic scattering is termed Raman scattering[.!

/ig! .2

 showing stokes and anti(stokes scattering

he arrows in /ig! . represent the difference in energies of the incident and scattered photons! Raman spectroscopy is associated with both stokes and anti(stokes scattering b+t

more so with the former!

∆ E=h ∆ v ..en. 1 Thi! i! the ener+ o% a #hoton $here h i!

#lanc45! con!tant& i! ener+ and ( the (elocit738.

 

h#o ( h#r h#f  ( h#iIIIe-n! 02 Represents a relation between incident and scattered

 photons![.

h#o represents the scattered photons and h#r represent the incident photons! he law of

energy m+st be conser#ed so that whene#er one is less h#o or h#r the change in energym+st be the same! his e-+ation represents the change in fre-+ency of the photons!

he motion of the scattered photons are collected by a $$5 system and transformed into

a spectra! "n detail spectrometers can detect these low le#el wa#elengths associated with

and transform these light energies into electrical signals[2! B+r spectrometer reads the

change in this wa#elength as cm(1 a form+la relates the fre-+ency to these raman shifts

cm(1['!

v́  1

 Λinc  (

1

 Λ  scattered IIIe-n 03[.(2 this e-+ation deri#es o+r Raman

shifts0cm(1 that we see on o+r spectra! hese shifts also represent the chemical bonds

that are located in a test s+bstance!

 GGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGG 1! Rayleigh scattering was disco#ered by 6ritish physicist Jord Rayleigh

2! =ict+re taken from so+rce[!!

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=resentation of 5ata

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Spectra for medium %ature ackee t&

Raman Spectra 'Small Ackee seed t(

Raman Spectra')arge Ackee seed t(

,i+. Sho$in+ raman !#ectra %or

" Small "c4ee (! ar+e "c4ee

%rom the !ame %ruit.

 

Spectra for a medium $mmature Ackee seed t&

,i+. 6 !ho$in+ a com#ari!on

bet$een medium !ied mature

and immature ac4ee !eed!.

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*eneral Raman Spectra

/ig! 4 showing a general Raman Spectra of A medi+m Ackee Seed from tD

• (

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5isc+ssion K Analysis

• A t(test was done on the Raman "ntensities0y #al+es fig!D and a res+lt of

1!9*1?81*(2D? was obtained this is E*!D and therefore statistically significant! /rom

/ig+re D it is clear that a smaller ackee seed0E2cm holds less chemical content

than a larger ackee seed0F2!Dcm, specifically the highest peakintensity on smallackee seed t3:(fig+re D is aro+nd the .,D** while on the corresponding large

ackee seed t3:(fig+re D its highest peak is abo#e 9***! So if there is some

hypoglycin content then it can be said that it0H@(A or H@(6 e8ists at higherle#els in the larger ackee seed!

• A t(test was completed on the Raman intensities for an immat+re ackee #s a

mat+re ackee of the same tree and a res+lt of *!2*.'9 was obtained! his is E*!Dand therefore statistically significant ! 6eca+se of the close pro8imity of peak

#al+es between the mat+re seed and the immat+re seed ass+mptions were made!

he first is that the time of capt+ring samples was relati#ely close0less than aweek so this co+ld e8plain why the chemical le#els are aro+nd the same! 7hat it

does not e8plain is the idea that the seed sho+ld lose some of its to8icity when

e8posed to the open air[1,?! /rom obser#ation fig!? it wo+ld seem that betweenthe shifts of 1D**(19**cm(1 that the peaks are higher in comparison to the mat+re

seed! his co+ld indicate presence of higher chemical le#els in that region!

•

/ig+re 4 shows +s the general Raman spectra for a medi+m si)ed immat+re ackeeseed! here are se#eral peaks on this graph that co+ld hint at chemical bonds

incl+ding the general form+la of Hypoglycin $4H11 B2! Hypoglycin(6 is what we

are really interested in as it is the largest component of H@ in the seed[1 andeasier to detect, chemical bonds of $B2H are a ma;or component this is

carbo8ylic acid and from o+r research[4 it lies in the raman shifts of 92*(9DDcm (1

! /rom all fig+res we can see peaks aro+nd the 9**cm(1 band and this co+ld be anindicator of the presence of this bond! H2, H, B and H are also present within

the chemical make(+p of Hypoglycin(6! Hydrogen and o8ygen bands occ+r and

o#erlap right across the shifts so their presence is more than likely! H or amino

gro+p occ+r shifts between 3*** and 3D**cm(1, +nfort+nately none of o+r spectra

allows +s to see shiftsbands in that range! An H bond may e8ist somewhere below 3*** b+t none of the reso+rces[4(2 has allowed +s to find that range!

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$oncl+sion

here isn:t eno+gh e#idence for +s to make the claim that by +sing Raman spectroscopy

we can detect the presence of any Hypoglycin component! Howe#er the peaks do point

o+t the presence of se#eral chemical components! 7hether these peaks from o+r spectrarelate to other +sef+l or harmf+l chemicals they can be +sed to facilitate f+rther research

+sing the Raman system on the ackee seed!

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References

1! 5+ndee >!S! S! K Cinott A! 5!02*11! Impact of seed si!e on residual hpoglcin

levels in ac"ee! /ood Research "nternational .4! 3*?L3*9

2!$olth+p, ! 6!, 5aly, J! H!, K 7iberley, S!

 #aman spectroscop! ohn 7iley K Sons! =!1(14

.! Horn R!02**9 $odern $ethods in eterogeneous *atalsis+ %cript to ,ecture

 #aman %pectroscop./rit)(Haber("nstit+te of the C=@

5epartment of "norganic $hemistry

D! 6oyle, 7! S!, K Smith, @!

System echnical >o+rnal, .90., D'4(D93!

? &ean,

=ress!

4! Socrates, @!, K Socrates, @! 02**1! "nfrared and Raman characteristic gro+p

fre-+enciesN tables and charts 0%ol! 2.D! $hichesterN 7iley! =g!12D(12'

'! Hager R!, Anderson >R! and R, 0194*! Theor of the -erivative %pectrometer , >! Bpt!

Soc! Am! ?*, 1...(1..9

9! 6ressler, R!, $orredor, $!, K 6rendel, &! 019?9! Hypoglycin and hypoglycin(like

compo+nds! =harmacological re#iews, 2102, 1*D(13*!

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Acknowledgements

• " wo+ld like to thank my classmates in partic+lar $heddi @rierson and Shanice 7hyte for their contrib+tions!

• " wo+ld also like to thank 5r! &!