Marine Sediment Reference Materials for Trace Metals and other Constituents
PACS-2 was collected in the harbour of Esquimalt, freeze dried and screened to pass a No. 120 (125 µm) screen and blended by Institute staff using the facilities of
CANMET, Mining and Mineral Sciences Laboratories, a division of Natural Resources Canada, in Ottawa.
The particle size distribution was characterized at NRC using a Horiba LA 920 Laser Scattering Distribution Analyser. Particle Size, µm
Median 12.9
Mean 19.2
Mode 14.2
Storage and Sampling
To ensure the stability of the organotin species it is necessary to store these materials at a temperature of -20°C. Prior to use, the bottle should be well mixed by rotation, shaken and tightly closed immediately thereafter.
Characterisation
Mean values submitted by selected laboratories participating in CCQM P-18, CCQM P-43 and CCQM K-28 were used to calculate the certified value and the uncertainty of characterization (uchar )[5].
Homogeneity
The material was tested for homogeneity at NRC. Also, randomly bottles were selected for the analysis by the participating laboratories. Results from different
bottles, as determined by ID-GC-ICP-MS, resulted in an uncertainty as reported in Table 2.
The homogeneity is warranted for samples of 500 mg and above.
Stability
Based on a 5 year study of the stability of tributyltin in PACS-2, an uncertainty component was assigned [6]. An uncertainty component associated with the short term stability (transport) was evaluated but considered insignificant. Measurements were conducted on samples stored for one month at -20°C, +4°C and 22°C. Keywords: Environmental material ; Particulate matter ; Soil/Sediment ;
Speciation analysis ; Tin speciation, Organometallics , Trace elements, Heavy metals |
