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1. WO2007107792 - PRÉPARATION DE COLLOÏDES D'ARGENT STABLES

Note: Texte fondé sur des processus automatiques de reconnaissance optique de caractères. Seule la version PDF a une valeur juridique

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CLAIMS
1 . A method for producing a silver colloidal solution by reducing silver nitrate with lithium citrate.
2. A method as claimed in Claim 1 , comprising the steps:
(a) heating a first quantity of water to a first predetermined temperature;

(b) adding a second quantity of silver nitrate to the water;
(c) heating the mixture to a second predetermined temperature;
(d) adding a third quantity of an aqueous lithium citrate solution to the mixture;
(e) maintaining the mixture at the second predetermined temperature for a predetermined time; and
(f) cooling the mixture.
3. A method as claimed in Claim 2, wherein the mixing process is carried out in a three-necked container.
4. A method as claimed in Claim 2 or 3, wherein the first predetermined temperature is 45°C.
5. A method as claimed in Claim 4, wherein the second predetermined temperature is 98°C.
6. A method as claimed in any of Claims 2 to 5, wherein the first quantity is 500ml of high purity water.
7. A method as claimed in any of Claims 2 to 6, wherein the second quantity is 90mg of said silver nitrate of 99.9999% purity;
8. A method as claimed in any of Claims 2 to 7, wherein the third quantity is 10ml of said aqueous lithium citrate solution.
9. A method as claimed in Claim 8, wherein the aqueous lithium citrate solution comprises 227mg of lithium citrate in 25ml high purity water.
10. A method as claimed in any of Claims 2 to 9, wherein the water and the mixture are stirred constantly throughout steps (b) to (f).
1 1 . A method as claimed in Claim 10, wherein the stirring is carried out using a stirrer rotated at 550rpm.
12. A method as claimed in any of Claims 2 to 1 1 , wherein in step (e) the predetermined time is 90 minutes.

13. A method as claimed in any preceding claim, wherein the resultant silver colloid has a narrow particle size distribution.
14. A method as claimed in Claim 13, wherein the mean particle size is 4nm.
15. A method as claimed in any of Claims 2 to 12, wherein the resultant silver colloidal solution is aggregated with organic or inorganic aggregating reagents for use in SERS and SERRS spectroscopy.
16. A silver colloidal solution formed by the reduction of silver nitrate with lithium citrate.
17. A silver colloidal solution as claimed in Claim 16, having high light scattering properties and producing intense SERS and SERRS spectra.