Magnetic Glass Particles, Method for Their Preparation and Uses Thereof

Abstract

This invention relates to magnetic particles having a glass surface which are substantially spherical. This invention also relates to methods for making them, as well as to suspensions thereof and their uses for the purification of DNA or RNA in particular in automated processes.

1 . A method for the production of a composition of magnetic glass particles comprising the steps of
 a) suspending magnetic objects with a diameter between 5 and 500 nm in a sol,   b) spray-drying the suspension in a two-nozzle spray-drier, and   c) sintering the spray-dried powder.   
     
     
         2 . The method of  claim 1   wherein   the inlet temperature of the two-nozzle spray-drier is between 120° C. and 500° C.,   the outlet temperature is chosen according to the boiling point of the sol and the spray pressure is at least 3 bar.   
     
     
         3 . The method of  claim 1   wherein   the inlet temperature of the two-nozzle spray-drier is between 170° C. and 230° C.   
     
     
         4 . The method of  claim 1   wherein   the inlet temperature of the two-nozzle spray-drier is 200° C.   
     
     
         5 . The method of  claim 1   wherein   the spray pressure is between 4 and 6 bar.   
     
     
         6 . The method of  claim 1   wherein   the sol contains ethanol as solvent.   
     
     
         7 . The method of  claim 6   wherein   the outlet temperature is between 50° C. and 300° C.   
     
     
         8 . The method of  claim 6   wherein   the outlet temperature is between 90° C. and 100° C.   
     
     
         9 . The method of  claim 1   wherein   the sinter temperature is between 400° C.   
     
     
         10 . The method of  claim 3   wherein   the inlet temperature of the two nozzle spray-drier is between 190° C. and 210° C.   
     
     
         11 . The method of  claim 9   wherein   the sinter temperature is between 720° C. and 770° C.