impurities in SDS (Lauryl sulfate, sodium salt)

Alex Dobrovic adobrovic at
Tue Mar 18 05:03:02 EST 1997

 We routinely use Sigma SDS (approx. 95% based on total alkyl sulfate
content), to make a 20%(w/v) stock, and have no problems using this in
procedures ranging from DNA preparation to Southern/ Northern

 We have found that our latest batch from Sigma goes a yellowish colour in
solution (20 % w/v), and forms a dirty brown precipitate if left
un-filtered. We have filtered it and used it for Northern and Southern
hybs. The probe and hyb conditions routinely work for us, but since we have
switched to the new batch of SDS they have stopped working. We are
currently testing the SDS to see if it is the cause of our problems. Has
anyone had a similar experience ?

 Hoping you can help,

Damian Hussey B.Sc(Hons)

Alexander Dobrovic, Ph. D.
Chief Scientist
Department of Haematology-Oncology
The Queen Elizabeth Hospital
Woodville, SA 5011, Australia

Affiliate Senior Lecturer
Department of Medicine
University of Adelaide

Tel 61-8-8222 6884
Fax 61-8-8222 6046 (note new numbers as of August 1996)

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