foundation for research and technology-hellas … of electronic structure and laser (iesl) ......

National Technical University of Athens

School of Applied Mathematical and Physical sciences

Foundation for Research and Technology-Hellas (FORTH)

Institute of Electronic structure and Laser (IESL)


School of Applied Mathematical and Physical sciences

Terahertz detection

of harmful residues in honey

Dr. M. Massaouti

PHOTOTECH: BIOSENSORS & BIOCHIPS21st-25th October 2013 , Athens , Greece

[email protected]


THz radiation and Food industry

2

Motivation

New methods for food analysis and inspection:

rapid portable (increase of testing capacity) non-destructive with no need of food pre-treatment real-time testing on the production line

Current analytical methods (few of them…)

High-performance liquid chromatography (HPLC)

Gas chromatography (GC)

mass spectrometry (MS)

nuclear magnetic resonance (NMR)

infrared spectroscopy (IR)

Fluorescence spectroscopy

Electrochemical (including also biosensors here), and so forth.

Contaminantsin food products

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Terahertz radiation

3

Molecular rotations ImagingLattice phononsSuperconductivity gap

Photonic “THz gap” Electronic

λ 10μm - 3mm

hν 120 - 0.413 meV

Hydrogen Bonds, Torsions, collective vibrational modes

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Terahertz radiation

4

Non–ionizing/invasive radiation

Transparent to non-conductingmaterials (paper, wood, plastic, etc.)

High sensitivity to water

Fingerprint spectrum:low-frequency torsional and vibrationalmotion of molecules

ImagingSecurity Drugs and explosives

Medical- Cancer

THz pump/probe

Plant stress

Ubiquitin: 76-residue, β-sheet protein

Protein folding DNA damage or repair

Discrimination of molecular structures

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THz radiation and Food industry

5

Detection of foreign bodies in food Non–ionizing/invasive radiation

Transparent to non-conductingmaterials (paper, wood, plastic, etc.)

High sensitivity to water

Fingerprint spectrum:low-frequency torsional and vibrationalmotion of molecules

Opt. Eng., 47 (3), 037003 (2007)

Moisture detectionJ Infrar. Milli. Terahz. Waves.33,97 (2012)

Grain wheat

Detection of Antibiotics/ pesticides (in milk, egg powders, rice, dried tomato)

Analyst, 136, 1733 (2012)IEEE Trans., 58, 7, 2064 (2010)

Appl. Spectr. Rev.,48, 439 (2013)

THz and Food industry

More to be done!!!

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Food industry: Honey

6

Honey: Natural and healthy product…….…..Polluted via different sources of contamination

(mainly to improper use of beekeeping practices)

Need: novel detection technologies rapid, non-destructive able todetermine the presence of multi-residues in honey.

Real-time detection

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Terahertz source

7

Broadband (0.1-35 THz), intense THz pulses (200 kV/cm)generated through 2-color femtosecond laser filaments in air.

THz source:

Coherent detection in time domain of the THz electric field.

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Terahertz source

8

Broadband (0.1-35 THz), intense THz pulses (200 kV/cm)generated through 2-color femtosecond laser filaments in air.

THz source:

Fourier transform the time signal

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THz time-domain spectroscopy (THz-TDS)

9

Refractive index

( )2ln

( )

S

R

Aa T

d A

Absorption coefficient:

( ) ( )1

s R cn

d

2( ( ) 1)

4 ( )

nT

n

( )( ) Ri

RA e

( )( ) si

SA e

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THz spectra: Antibiotics & Acaricides

10

Concentration 20% w/w

Thickness ~1 mm

Diameter 7 mm

Weight 40 mg

SAMPLE HOLDER(pellets)

PELLETS: mixture of HDPE powder + chemical compound

Antibiotics

Sulfapyridine

Sulfathiazole

Tetracycline

Acaricides Coumaphos

Amitraz

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THz spectra : Antibiotics

11

Sulfapyridine

Sulfapyridine

Sulfathiazole

Tetracycline

Tetracycline

THz region (0.5-2.6 THz)

1.064 THz

Sulfathiazole

1.88 THz2.04

Distinct resonance peaks in the THz regime

Massaouti et al. J. Appl. Spectr. (2013)

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THz spectra : Acaricides

12

Coumaphos

Amitraz


1.88 THz

Amitraz

Coumaphos

Distinct resonance peaks(0.5-2.6 THz)

↓Discrimination of:

Sulfapyridine

Sulfathiazole

Coumaphos


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THz spectra : Antibiotics

13

Sulfapyridine

Sulfathiazole

Tetracycline


Amitraz

Coumaphos

Detection in a wider THz region0.5-6.0 THz

↓Additional resonance peaks

↓Discrimination of:

Sulfapyridine

Sulfathiazole

Coumaphos

Amitraz

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THz spectrum of honey

14

SAMPLE HOLDER(liquids)

HDPE

Spacer 620 μm

Highly absorptive: α = 50 cm-1 (1 THz)

Refractive index: n = 1.8


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Sulfapyridine in honey

15


HDPE

Spacer 620 μm

+

Mixture:

Sulfapyridine Honey

different concentrations(w/w)

1.064 THz

.

mixture honey sylfapyridine

mixture

THz ref

A

A


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Sulfapyridine in honey

16


HDPE

Spacer 620 μm

+

Mixture:

Sulfapyridine Honey

different concentrations(w/w)

1.064 THz

Detection of Sulfapyridine in honey at relatively low concentrations (1% w/w)

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Sulfapyridine & Sulfathiazole in honey

17

+

Mixture:

Sulfapyridine (9%)

Honey

andSulfathiazole (11%)

binary mixture honey honey/ /

,

i ii

B

i sulfapyridine sulfathiazole

Multiple residues in honey

Potential of THz-TDS to be used in the near future as a fast, real-time technique for detecting and discriminating multi-residues strictly related

to food safety issues.


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Ultrashort Nonlinear Interactions and Sources Lab

Acknowledgments

UNIS - THz group

Prof. S. Tzortzakis (Head of the UNIS group)

Dr. M. Massaouti

Dr. A. Gorodetsky

M. Loulakis

T. Koulouklidis

C. Daskalaki

http://www.iesl.forth.gr/

LASERLAB-EUROPE

UNIS group

http://unis.iesl.forth.gr/

http://www.iesl.forth.gr/

http://unis.iesl.forth.gr/

foundation for research and technology-hellas … of electronic structure and laser (iesl) ......

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