About the storage of the standard (of cource acidified) I have a few
answers for you:
1. Merck company supply a ICP multielement standard (30 elements - must of
them at the level of 10 ppm) in a PVDFcontainer guaranteed for about 3 years.
2. NIST supply SRM 1643d - trace elements in water ( at levels between
1-500 ppb depending on each element)) in container LDPE guaranteed for 2 years .
3. National Research Council Ottawa Canada (NRC), supplied a standard
SLRS-1(in a LDPE container which had be pretreated with acid), Riverine
Water Reference Material for Trace Elements at levels betwen 15 ppt -136 ppb
, 12 years ago (1986-87). We analyzed this material 2 weeks ago and we
received the certificate values for all elements.
4. The same NRC supplied also a NASS-1 - Seawater Standard with
certificate values for trace elements at levels 4 ppt -12 ppb in 1982 with
were warranted for a 2 year period. I analyzed this standard for 8 elements
in 1993 and received the certificate values.
Please make your own conclusions.
Dr. Ludwik Halicz, Head ICP-MS Lab.
Geological Survey of Israel
30, Malkhey Israel St.
95501 Jerusalem, Israel
tel: (972)(2)5314205 Fax: (972)(2)5380688
e-mail [log in to unmask]