HIGH RESOLUTION ULTRASOUND SPECTROSCOPY IN HUMIC RESEARCH

Miloslav Pekař Jiří Kučerík

Daniela Šmejkalová Martina Klučáková

Institute of Physical and Applied Chemistry

Faculty of Chemistry

Brno University of Technology

Brno, Czech Republic

? • ULTRASOUND SPECTROSCOPY • ?

TRADITIONAL SPECTROSCOPY

sample

electromagnetic wave

ULTRASOUND SPECTROSCOPY

ultrasound wave(mechanical)

ULTRASOUND INTERACTION WITH MATTER

                                                                     

        

intermolecular forces probe

microelasticity

ULTRASOUND FREQUENCY

method Hz

UV 1014-1016

VIS 1014

IR 1012-1014

NMR 106-108

US 106-108

ULTRASOUND PARAMETERS

• velocity ...

• amplitude (attenuation) ......

... elasticity, density •

...... energy loss •

ULTRASOUND VELOCITY

elastic response• dominating • sensitive to molecular organization, intermolecular interactions

v

solids

liquids

gasesrigidity . . . velocity

ULTRASOUND ATTENUATION

heterogeneous sample• scattering • particle sizing

homogeneous sample • local relaxation

HIGH RESOLUTION

RESOLUTIONhighnormal

ATTENUATION

VELOCITYVELOCITY

0.1 m/s 0.0001 m/s

(10-5%)

0.2% 0.2%

EXAMPLE – MICELLES

hydrophobic core . . . higher elasticity

EXAMPLE – CONFORMATION CHANGES

temperature ramp - polyacrylamide

EXAMPLE – LIGAND BINDING

Mg2+ to polyriboadenilic acid

EXAMPLE – AGGREGATION

carbonic anhydrase, temperature induced

EXAMPLE – MICROEMULSION

lipid+surfactant+cosurfactant and water

QUANTITATIVE INTERPRETATION – PRINCIPLES

velocity of sound

2/10)ρ/( Pu )/ρ)(ρ/1(β P

sound – longitudinal wave• causes local variation of the density, pressure

• finite compressibility energy transports across the space

compressibility

2/1)βρ/1(u

QUANTITATIVE INTERPRETATION – DECOMPOSITION

DILUTE SOLUTIONS

(adiabatic)

apparent molar volume

20

11V /)(φ nVnV

apparent molar compressibility

20

11KS /)ββ(φ nn

solution solute

solvent

hMV Δφ VV rhMKS Δφ KKK

M…solute h…hydration r…relaxationcontributions

QUANTITATIVE INTERPRETATION – CONCLUSION

concentration increment of ultrasound velocity

KM …constantKr …from frequency dependence of attenuationKh …evaluated

)ρ/()( 000 muuuA

solutionsolvent

molality

)β2/()Δ(Δ)Δ(ΔΔ 0hh KVA

NaHu - CONCENTRATION

NaHu + ACID … KINETICS

0.5g/L NaHu

pH: 7 3.5

NaHu + ACID … VELOCITY

-0.08

-0.06

-0.04

-0.02

0

0.01 0.05 0.08 0.1 0.2 0.5 0.8 1 2

NaHu concentration (g/L)

velo

city

cha

nge

(m/s

)

HCl

NaHu + ACID … VELOCITY

NaHu concentration (g/L)

velo

city

cha

nge

(m/s

)

-0.1

0

0.1

0.2

0.3

0.01 0.05 0.08 0.1 0.2 0.5 0.8 1 2

propionic

NaHu + PROPANOL … VELOCITY

NaHu concentration (g/L)

velo

city

cha

nge

(m/s

)

-0.2

-0.15

-0.1

-0.05

0

0.05

0.01 0.05 0.08 0.1 0.2 0.5 0.8 1 2

propanol

Cu2+ + SALYCILIC ACIDve

loci

ty (

m/s

ec)

1496

1498

1500

0 10000 20000 30000 40000

time (sec)

blank

sample

THANKS …

… for your attention