Table A9: Typical QC used with each batch of analytical soil samples for inductively coupled plasma - mass spectrometry analysis
Return to the point in the document where this table is located.
| Typenfection, trou | Frequency | Warning limit(a) | Control limit(b) | Action on failure |
|---|---|---|---|---|
|
Blank |
Beginning of each run |
< detection limit |
Repeat whole run |
|
|
Duplicate |
10% |
20% |
Repeat whole run |
|
|
Spikes |
Not used(c) |
|||
|
QC standard(d) |
Beginning of each run |
10% |
20% |
Fix problem (usually instrumental) before repeating run |
|
QC sample(e) |
3 per batch |
10% |
20% |
Re-digest samples and re-analyse |
|
Certified reference material |
At validation, then as required |
Within certified range |
Re-digest samples and re-analyse |
Notes:
a) Warning limit - Variation outside which the laboratory would take special note of the analyses QC trends.
b) Control limit - Maximum acceptable variation outside which analyses would usually be repeated.
c) Spiked soil samples are not used as it is virtually impossible to spike a soil in a way that has the same form as the analyte already in the matrix.
d) Obtained from an independent source to the working standards used.
e) A thoroughly homogenised sample that has been well characterised by multiple analyses over time.
