Basic HTML Version
Appendix B
5/20/2009
17
12. DATA ANALYSIS AND CALCULATIONS
12.1.
Raw results for each run are printed by the dot matrix printer attached to the
instrument. These data are then manually entered into a LOTUS 123 spreadsheet.
Results are reported in mg/l for aqueous samples, and in % for sediment or other
weighed samples, standards and SRMs or QCSs.
12.2.
Recalculation of data (if necessary)
12.2.1. The software gives the analyst the opportunity to recalculate values generated
by the run. This option can be useful for adjusting the values of the data due to
explained or unexpected changes in the blank or calibration (K) factor during an
analytical run cycle. Blanks can change due to sample handling, different
capsules or sleeves, small leaks in the system and contamination. K factors should
remain stable but can drift due to flow changes caused by variable pressure drops
in the traps or helium scrubber, or by changing delivery pressure at the helium
regulator.
12.2.2. Before the analyst can change calibration values and recalculate the results,
there must be a valid reason.
When data is recalculated, always document the
incident.
12.3.
Example of LOTUS spreadsheet of results:
A
B
B
C
D
E
1
2/29,3/3/08
2
Jane Doe
3 DNR MAINSTEM SPLITS
4
2/08
5
SAMPLE MG N/L
MG C/L
6
56 0.1440
0.9520
7
57 0.1510
0.9980
8
58 0.1440
0.9460
9
59 0.1430
0.9260
10
BCSS1, 2/29
0.20
2.09
%
11
BCSS1, 3/3
0.20
2.14
%
12
LAB DUPS
PN
PC
13
SAMPLE DUP 1
DUP 2 DUP 1
DUP 2
14
56 0.1430
0.1460 0.9360
0.9670
15
58 0.1430
0.1450 0.9470
0.9450
17
BLANKS N= 16
K VALUE N= 7.493
18
C= 140
C= 20.771
19
BLANKS N= 15
K VALUE N= 7.393
20
C= 126
C= 20.352