We use in our lab the buffer from Sigma. It works very well. The order number is B4930 geneart GmbH Dipl. Ing. Martin Maier Josef-Engert-Stra=DFe 9 D-93053 Regensburg Germany Tel.: +49-(0)941-9427618 Fax: +49-(0)941-9427611 E-mail: martin.maier at geneart.de http://www.geneart.de ---