Identificación de complejos organometálicos en tejidos vegetales mediante espectrometría de masas

32 

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(1)

Identificación de complejos organometálicos en

tejidos vegetales mediante espectrometría de

masas

R Rellán-Álvarez, J Abadía and A Álvarez-Fernández

Plant Stress Physiology Group,

Aula Dei Experimental Station, CSIC, Zaragoza

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chloroplast

AtCCC1

AtIRT2

AtVIT1

AtSLB AtPIC1

vacuole

leaf

xylem

root

Modified from Abadía J, 2006, Pers. Com.

Metal Speciation: A complex

(ed)

story

FRU/FIT/bHLH

PS

AtFRD3

AtYSL2

Cit

OsFRDL1

AtYSL2

AtZIP8

AtFRO3

AtNRAMP3,4

OsYSL2

Fe(II)

AtIRT1

H

+

Fe(III)

AtFRO2

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Hyphenated techniques available for species-selective analysis of biological materials

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Hyphenated techniques available for species-selective analysis of biological materials

Separation

Detection

Identification

Metal Specific

Compound Specific

HPLC

ICP-MS

ESI-TOF-MS

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Main problems and bottlenecks

-Sample extraction: should conserve the plant compartment conditions

for example pH values.

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Main problems and bottlenecks

Ligand Exchange

pH Dependance

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Main problems and bottlenecks

-Sample extraction: should conserve the plant compartment conditions

for example pH values.

-These conditions should also be conserved during separation and detection.

-If this conditions a

-Sensitivity: very low concentration of metals in plant tissues.

-Cost: expensive equipment.

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Integrated mass spectrometry in (semi-)metal speciation

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HPLC-TOFMS

time (HPLC)

m/z

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HPLC-TOFMS Mass spectra at an specific time

m/z

5.9 min

m/z

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HPLC-TOFMS

m/z

TOFMS

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HPLC-TOFMS Chromatogram of an specific m/z

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HPLC-TOFMS

m/z

TOFMS

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Compound identification based on isotopic signature

Isotopic discrimination

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Compound identification based on isotopic signature

Isotopic distribution

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Compound identification based on isotopic signature

Isotopic discrimination

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Compound identification based on isotopic signature

Kind and Fiehn, 2006

Mass accuracy

vs

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!  

Results

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ESI and HPLC Optimization of Standard Solutions

Fe

2

Cit

2

Fe

3

Cit

3

Fe:Cit 1:10

pH 5.5

Fe-Cit in xylem

Rellan-Alvarez et al

in press

(23)

Isotopic signature

nat

Fe

Fe

2

Cit

2

Fe

3

Cit

3

Fe-Cit in xylem

Rellan-Alvarez et al

in press

(24)

Isotopic signature

Fe

2

Cit

2

Fe

3

Cit

3

Fe

2

Cit

2

Fe

3

Cit

3

Fe-Cit in xylem

Rellan-Alvarez et al

in press

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and molecular formula determination

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Fe:Cit ratios drive the formation of Fe-Cit complexes

Evans, JBIC, 2008

Fe-Cit in xylem

Rellan-Alvarez et al

in press

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Plant Material

Tomato Fe-deficient Plants

Resupplied with Fe 45 µM

Fe-Cit in xylem

Rellan-Alvarez et al

in press

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(29)
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ICP-MS

Tomato Xylem Sap samples

Fe

3

Cit

3

Fe

3

Cit

3

Fe

3

Cit

3

54

Fe

Fe-Cit in xylem

Rellan-Alvarez et al

in press

(31)

An oxo-bridged Fe

3

Cit

3

complex

µ

3-

oxo-bridged center

Octahedral config.

H-bonds

Distal carboxylate groups

Central carboxylate group

Size: 1.1 x 0.4 nm

C

Fe

O

H

Fe-Cit in xylem

Rellan-Alvarez et al

in press

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Gràcies!

Javier Abadía

Ana Álvarez

Irene Orera

Justo Giner

Jose. I.García

J. A. Rodríguez

Jesús Orduna

University of Oviedo

University of Zaragoza

ICMA

Luis E. Hernández

UAM, Madrid

Sandra Carrasco

Figure

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Referencias

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