Following the spirit of this Tom's comment, temperature equilibration is a "must" that applies to both standards and samples. If you'll pipette and weigh successive aliquots of a "cold" sample, you'll notice significant differences in the volumes pipetted. Changing "headspace" temperatures in air-displacement pipettes (such as Eppendorfs) can result in your transferring more sample than you intend.
Robert J. Taylor, Ph.D.
Trace Element Research Laboratory
Dept. of Oceanography
Texas A&M University
College Station, TX 77843
e-mail: [log in to unmask]
From: TOM HINNERS [SMTP:[log in to unmask]]
Sent: Thursday, June 11, 1998 12:43 PM
To: [log in to unmask]
Subject: storage of standards -Reply
I just wanted to offer a warning for your information. If you
aspirate solutions for analysis, low calibrations were reported
several years ago when refrigerated standard solutions were
not allowed to warm (before the analysis of ambient-
temperature solutions). A discrepancy in the data might also
arise if you immediately analyze (or analyse) refrigerated
water samples using unrefrigerated standard solutions.
>>> M van Schalkwyk
<[log in to unmask]> 06/09/98 05:07am
Does anyone have a reference or a lab techniques document
which will be any
help in figuring out the best state in which to store low level
ICP-AES? Especially ones used for trace analysis of water
samples (ie 0.2ppm
and up to around 5ppm). I'm especially interested in the
length of time it
takes for the concentrations/peaks of certain more 'mobile'
Thanx in advance for your help
Martina van Schalkwyk
COUNCIL FOR GEOSCIENCE
fax: +27 12 8411278
phone: +27 12 8411275