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Study of Pesticides
Used in Agriculture
by X-Ray
SpectrometryFelipe Porto Ribeiro
Delson Braz
Leonardo Rodrigues
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Summary
• Introduction
• Objectives
• Theory
• Pesticides
• Methods
• Results
• Conclusions
• References
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Introduction
Our motivation
•Natural products have been replaced by artificial ones, to
ensure agricultural production to competitive levels .
•As one of the largest producers and exporters of food, Brazil is
today the largest consumer of pesticides in the world.
•Pesticides, however, are still pretty dangerous to human health
and to the environment.
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Objectives
• Determine if the detection of food contamination by
pesticides using x-ray diffraction are viable.
• We used one of the most common techniques in this field in
developing this work:
The X-ray diffraction by the powder method
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Theory
• Interactions of Electromagnetic Radiation with Matter
• Photoelectric Effect
• Compton Effect or Incoherent Scattering
• Classic or Coherent Scattering
• The incident energy causes excitation of the atom and the
consequent release of a photon of energy equal to the incident;
• At low angles or regions of low momentum this effect allows to
determine the composition of the material.
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Low
energies
• Bragg's law
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7/17X-ray diffraction by a crystal (CULLITY, 1978)
8
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)('2 θλ sendn =
)()/'(2 θλ sennd=
)(2 θλ dsen=-n is an integer determined
by the order given.
-λ is the wavelength
-d’ is interplanar distance
Pesticides
• We studied five pesticide of the classes of fungicides and
insecticides whose active principles are:
• Imidacloprido – Trademark A;
• Ciromazina – Trademark B;
• Diafentiurom – Trademark C;
• Dimetomorfe – Trademark D;
• Famoxadona – Trademark E;
• Mancozebe – Trademark E.
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Seeds
• We studied organic and
conventional bean
seeds;
• Peels and pulps were
contaminated, dried and
crushed to the state of powder.
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Methods
• Pesticides Preparation
• The pesticides were crushed with mortar and pestle until the
state of powder. Party was housed in the sample holder (three
for each active principle) and part was intended for process
contamination.
• Contamination Process
• Pulp and peel were separated after immersion in water.
• For each trade mark groups were used on both sides to be
contaminated at concentrations of 1, 3, 5, 10 and 15% of active
principles diluted in distilled water.
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Analysis by X-Ray Diffraction
• To obtain the profiles of diffraction we used Shimadzu XRD
6000 diffractometer belonging to LIN - PEN / COPPE / UFRJ.
• Radiating a sample at an angle and intensities predetermined;
• The data are then collected by XRD 6000© software and used to
construct a graph which correlates the radiation measured by the
detector with the scattering angle (2ϴ).
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Results
• Profiles raised:
• One for each active ingredient;
• Peel and pulp of organic beans;
• Peel and pulp of beans conventional uncontaminated;
• Peel and pulp bean conventional sources (1, 3, 5, 10 and 15%).
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• Control group (organic bean)
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0 20 40 60
0,0
0,8
1,6
In
ten
sid
ad
e n
orm
aliz
ada
2θ (graus)
casca 0% (GrupoI)
casca orgânica
0 20 40 60
0,0
0,8
1,6
In
tensid
ade
no
rmaliz
ada
2θ (graus)
polpa 0% (Grupo I)
polpa orgânica
Diffractogram of the
organic bean peel from
Group I (0%).
Diffractogram of the
organic bean pulp from
Group I (0%).
• Convencional bean
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0 20 40 60
0
2
4
6
In
ten
sid
ad
e n
orm
aliz
ada
2θ (graus)
casca 15% (GVI)
casca 10% (GV)
casca 5% (GIV)
casca 3% (GIII)
casca 1% (GII)
casca 0% (GI)
Diffractogram of the
contaminated and
uncontaminated bean
peel with 1% 3% 5% 10%
and 15% of the pesticide
trademark A.
0 20 40 60
0
2
4
6
Inte
nsid
ad
e n
orm
aliz
ada
2θ (graus)
polpa 15% (GVI)
polpa10% (GV)
polpa 5% (GIV)
polpa 3% (GIII)
polpa1% (GII)
polpa 0% (GI)
Diffractogram of the
contaminated and
uncontaminated bean
pulp with 1% 3% 5% 10%
and 15% of the pesticide
trademark A.
Conclusions
• The beans sold conventionally not present traces of pesticide
contamination.
• In the analysis of pulp and peel was not possible to identify
any contamination by pesticides in any percentage.
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References• RODRIGUES, L. ESTUDO DE AGROTÓXICOS USADOS EM AGRICULTURA
ATRAVÉS DA TÉCNICA DE DIFRAÇÃO DE RAIOS X. Rio de janeiro: UFRJ/COPPE, 2012.
• ANVISA. Agência Nacional de Vigilância Sanitária, 2011. AGROTÓXICOS E TOXICOLOGIA. Disponível em: HTTP://www.anvisa.gov.br/. Acesso em: 20 ago. 2011.
• ANVISA, 2006, “RESÍDUOS DE AGROTÓXICOS EM ALIMENTOS”. Rev. Saúde Pública, 40(2), 361-363.
• CULLITY, B.D., 1978, ELEMENTS OF X-RAY DIFFRACTION. 2. ed Reading, Mass., Addison-Wesley.
• DULONG, F. T., JACKSON, J. C., 1997, X-RAY POWDER DIFFRACTION. U. S. Geological Survey.
• MONTGOMERY, D. C.; RUNGER, G. C. 2003, APPLIED STATISTICS AND PROBABILITY FOR ENGINEERS. 3ª ed. John Wiley & Sons.
• STENERSEN, J., 2004, CHEMICAL PESTICIDES: MODE OF ACTION AND TOXICOLOGY. CRC PRESS.
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