Report No xxxx - Instytut Fizyki JÄ drowej PAN

R 1
[1/s]
10
8
6
4
1% LMP solution
1% LMP sol state (2.5mM CaCl 2
)
1% LMP sol state (5mM CaCl 2
)
1% LMP gel state (7.5mM CaCl 2
)
1% LMP gel state (10mM CaCl 2
)
Fig. 1. Dispersion of the water 1 H spin-lattice
relaxation rate in solution of 1% w/w pectin
without added calcium chloride and after
addition of 2,5; 5; 7.5 and 10 mM CaCl 2.
2
0
10 4 10 5 10 6 10 7
Larmor frequency [Hz]
The existence of gelling process was confirmed by spin-spin relaxation times
measurements. T 2 relaxation curves were bi-exponential. It can be associated with water in
differing physical environments (away from the pectin macromolecules - long T 2 and near
macromolecular surfaces – short T 2 ). With increasing concentration of the salts increases
number of junction zones and sites of cross-links, due to the long component of transverse
relaxation times decreases - around five times (from 1.13 s to over 0,23 s ). These results
indicates that in the gelled system pectin molecules more rapidly exchange spin energy with
water molecules [3].
1,2 tau CPMG
= 1ms
T 2
slow
1,0
T 2
fast
0,8
Fig. 2. The spin-spin relaxation times for
1% w/w pectin solution without added
calcium chloride and after addition of 1.5;
2.5; 5; 6.5; 7.5 and 10 mM CaCl 2.
T 2
[s]
0,6
0,4
0,2
0,0
0 2 4 6 8 10
CaCl 2
concentration [mM]
1. G. T. Grant, E. R. Morris, D.A. Rees, P. J. C. Smith, and D. Thom, FEBS Lett., 32, (1973) 195.
2. M. Dobies, M. Kozak, S. Jurga, Solid State NMR 25, Iss. 1-3, 2004 (in press)
3. B. Halle, H. Johannesson, and K. Venu, J. Magn. Reson., 135, (1998) 1.
4. W. L. Kerr, and L. Wicker, Carbohydr. Polym., 42, (2000) 133.
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