Table 8. Results of holding-time study using three fortified ground waters.
Concentration ( X S)**
(g/L)
Preserved
Analyte/matrix*
(pH 2.0)
Day 0
Day 3
Day 7
Day 14
Day 28
Day 64
53.1 1.39
51.4 0.30
51.3 0.41
35.2 0.20
18.4 0.22
7.9 0.04
TNB
1
No
51.8 0.69
51.2 0.07
56.7 1.96
53.9 0.30
53.5 0.47
51.8 0.56
Yes
52.4 0.58
52.3 0.49
54.7 0.18
45.2 0.51
33.8 0.93
16.5 1.20
2
No
52.8 1.56
52.0 0.10
54.9 0.13
54.0 0.35
54.6 1.42
53.4 0.62
Yes
53.6 0.62
52.5 0.09
53.4 0.54
42.2 0.85
20.7 0.68
4.2 0.60
3
No
52.7 0.81
52.9 0.04
55.6 0.15
54.8 0.46
56.6 0.26
54.7 0.16
Yes
42.5 1.17
39.2 0.02
29.0 0.28
13.9 0.58
7.2 0.01
3.0 0.13
tetryl
1
No
41.5 0.67
41.6 0.53
45.8 0.39
43.1 0.13
42.7 0.41
39.5 0.44
Yes
41.4 0.48
39.7 0.48
38.6 0.48
25.8 0.27
14.4 0.02
3.7 0.80
2
No
41.5 1.54
41.6 0.40
44.4 0.53
42.6 0.72
42.4 0.11
40.4 0.42
Yes
170.3 0.1
168.5 0.0
147.4 2.5
83.1 0.48
70.2 0.01
26.3 0.53
3
No
170.8 0.6
173.7 2.0
179.9 3.5
174.7 2.2
176.3 0.1
158.4 0.63
Yes
89.4 2.27
89.1 0.24
93.3 0.45
80.9 0.43
74.6 0.89
61.8 1.05
TNT
1
No
88.3 0.71
91.0 0.75
96.1 2.96
92.6 0.98
90.7 1.15
91.6 0.60
Yes
89.9 1.18
91.8 1.45
94.0 0.40
85.4 1.05
74.1 2.25
63.4 0.37
2
No
89.1 2.82
92.1 0.96
94.6 0.76
92.5 0.02
92.3 1.73
91.5 0.29
Yes
90.5 1.51
91.3 0.26
94.7 0.96
88.1 0.84
80.2 0.18
62.5 0.51
3
No
88.5 0.07
93.5 1.82
95.0 0.15
89.9 0.48
94.3 0.11
92.7 0.27
Yes
56.0 1.67
55.7 0.32
57.5 0.16
56.9 0.01
56.5 0.04
56.4 0.87
4-ADNT
1
No
55.3 1.29
45.2 0.47
39.6 0.22
34.8 0.16
35.0 0.31
31.1 0.10
Yes
55.5 0.94
55.7 0.23
57.0 0.46
56.5 0.17
54.6 1.13
54.5 0.42
2
No
56.2 1.69
45.9 0.32
41.0 0.71
36.1 1.56
32.7 1.00
29.8 0.14
Yes
54.3 2.07
51.1 2.79
55.8 1.80
54.9 0.28
53.4 0.38
54.5 0.25
3
No
54.6 0.46
47.8 1.85
45.2 0.52
41.4 0.76
40.9 1.02
38.7 0.15
Yes
* Matrix 1 = PT, matrix 2 = MW, matrix 3 = TR
** X = mean; S = standard deviation
To determine if these losses could be eliminated
acidified samples compared with unacidified. Pre-
using Teflon cap liners, a study was conducted as
served and unpreserved samples were prepared
follows. Reagent-grade water was fortified with
and treated as described for the previous study,
TNT, NB, the three nitrotoluenes, and the two
except that only duplicates were analyzed for each
DNTs. Samples were stored in an inverted posi-
storage time. The results of this study are shown
tion, under refrigeration, and analyzed after 7, 14,
in Table 8.
28, and 64 days. No measurable losses were ob-
60
served. Thus, the losses for this group of analytes
would have been eliminated if vials using
Teflon cap liners had been used in the holding-
time study.
40
Holding-time study using
pH 2 stabilization for
fortified groundwaters
Since preservation by acidification to pH 2
was successful for most of these compounds in
Connecticut River water, an additional study was
20