Metals
113
Digestions on dried (lOS °C) sediments (0.5 g) were performed in PTFE beakers
using hydrochloric acid (5 ml), nitric acid (2 ml) hydrofluoric acid (5 ml), and water
(4 ml) for 2 h at 90°C. After gentle evaporation to dryness, a further 5 ml of concentrated nitric acid and 2 ml perchloric acid were added and the solutions again taken to
dryness. The residue was dissolved in 20 mIl mol I-I hydrochloric acid, filtered, and
made up to 50 ml with water.
It is shown in Table 5.1 that determined results are in good agreement with reference values for all seven elements.
Table 5.1
Comparison of graphite furnace atomic absorption spectrometry results with accepted
values for MESS-I (from [331])
Element
Concentration (Ilg g-l). by different
methods
Standard additions
L'vov Platform
Cd
Pb
Cu
Ni
Co
Be
Cr
Direct
injection
0.54 ± 0.06 (9)
26.4 ± 2.7 (9)
21.9 ± 2.3 (B)
2B.7 ± 2.9 (10)
11.7 ± I.B (14)
I.B ± 0.2 (B)
70.3 ± 5.0 (6)
Chelationextraction
0.5B ± 0.11 (9(
2B.2 ± 6.5 (9)
25.4 ± 3.0 (10)
31.2 ± 4.1 (11)
12.2 ± 2.7 (11)
ND c
ND
Direct
injection
0.65 ± 0.13 (3)
27.3 ± 1.6 (3)
21.3 ± 1.6 (3)
2B.6 ± 4.B (3)
11.7 ± 2.9 (3)
I.B ± 0.1 (3)
ND
Accepted
value
0.59 ± 0.1
34.0 ± 6.1 b
25.1 ± 3.B
29.5 ± 2.7
1O.B ± 1.9
1.9 ± 0.2
71 ± 11
Comparison of graphite furnace atomic absorption spectrometry results with accepted values for
BCSS-l
Element
Cd
Pb
Cu
Ni
Co
Be
Cr
Concentration (Ilg g-l). by different methods
Standard additions
L'vov Platform
Direct
ChelationDirect
injection
extraction
injection
0.24 ± 0.04 (9) 0.26 ± 0.10 (3) 0.23 ± 0.03 (3)
22.0 ± 3.0 (6)
22.0 ± 10.1 (3) 20.0 ± 5.4 (3)
15.0 ± 3.4 (3)
16.2 ± 2.2 (4)
14.6 ± 2.5 (3)
54.7 ± 5.1 (7)
56.6 ± 5.0 (5)
53.0 ± 2.2 (3)
12.7 ± 3.6 (3)
11.9 ± 6.9 (3)
10.7 ± 1.3 (3)
1.1 ± 0.2 (B)
NDc
1.1 ± 0.1 (3)
122 ± 7 (6)
ND
ND
Accepted
value
0.25 ± 0.04
22.7 ± 3.4
IB.5 ± 2.76
55.3 ± 3.6
11.4 ± 2.1
1.3 ± 0.3
123 ± 14
• Precision expressed as the 95 % confidence interval for a single result. (n) = number of determinations
b Accepted value excludes results from graphite furnace atomic absorption spectrometry
C Not determined
d B ml of dissolved sediment diluted with 30 milO mol I-I hydrochloric acid, iron removed by
extraction with MIKB. Digest evaporated to dryness and diluted to 100 ml with water. 10 ml aliquot
diluted to 50 ml with water used to prepare standard addition plot by extracting samples with
ammonium pyrralidone diethyl dithiocarbamate in MIKB. Then trace metals back extracted into
5 ml mol I-I nitric acid
113
Digestions on dried (lOS °C) sediments (0.5 g) were performed in PTFE beakers
using hydrochloric acid (5 ml), nitric acid (2 ml) hydrofluoric acid (5 ml), and water
(4 ml) for 2 h at 90°C. After gentle evaporation to dryness, a further 5 ml of concentrated nitric acid and 2 ml perchloric acid were added and the solutions again taken to
dryness. The residue was dissolved in 20 mIl mol I-I hydrochloric acid, filtered, and
made up to 50 ml with water.
It is shown in Table 5.1 that determined results are in good agreement with reference values for all seven elements.
Table 5.1
Comparison of graphite furnace atomic absorption spectrometry results with accepted
values for MESS-I (from [331])
Element
Concentration (Ilg g-l). by different
methods
Standard additions
L'vov Platform
Cd
Pb
Cu
Ni
Co
Be
Cr
Direct
injection
0.54 ± 0.06 (9)
26.4 ± 2.7 (9)
21.9 ± 2.3 (B)
2B.7 ± 2.9 (10)
11.7 ± I.B (14)
I.B ± 0.2 (B)
70.3 ± 5.0 (6)
Chelationextraction
0.5B ± 0.11 (9(
2B.2 ± 6.5 (9)
25.4 ± 3.0 (10)
31.2 ± 4.1 (11)
12.2 ± 2.7 (11)
ND c
ND
Direct
injection
0.65 ± 0.13 (3)
27.3 ± 1.6 (3)
21.3 ± 1.6 (3)
2B.6 ± 4.B (3)
11.7 ± 2.9 (3)
I.B ± 0.1 (3)
ND
Accepted
value
0.59 ± 0.1
34.0 ± 6.1 b
25.1 ± 3.B
29.5 ± 2.7
1O.B ± 1.9
1.9 ± 0.2
71 ± 11
Comparison of graphite furnace atomic absorption spectrometry results with accepted values for
BCSS-l
Element
Cd
Pb
Cu
Ni
Co
Be
Cr
Concentration (Ilg g-l). by different methods
Standard additions
L'vov Platform
Direct
ChelationDirect
injection
extraction
injection
0.24 ± 0.04 (9) 0.26 ± 0.10 (3) 0.23 ± 0.03 (3)
22.0 ± 3.0 (6)
22.0 ± 10.1 (3) 20.0 ± 5.4 (3)
15.0 ± 3.4 (3)
16.2 ± 2.2 (4)
14.6 ± 2.5 (3)
54.7 ± 5.1 (7)
56.6 ± 5.0 (5)
53.0 ± 2.2 (3)
12.7 ± 3.6 (3)
11.9 ± 6.9 (3)
10.7 ± 1.3 (3)
1.1 ± 0.2 (B)
NDc
1.1 ± 0.1 (3)
122 ± 7 (6)
ND
ND
Accepted
value
0.25 ± 0.04
22.7 ± 3.4
IB.5 ± 2.76
55.3 ± 3.6
11.4 ± 2.1
1.3 ± 0.3
123 ± 14
• Precision expressed as the 95 % confidence interval for a single result. (n) = number of determinations
b Accepted value excludes results from graphite furnace atomic absorption spectrometry
C Not determined
d B ml of dissolved sediment diluted with 30 milO mol I-I hydrochloric acid, iron removed by
extraction with MIKB. Digest evaporated to dryness and diluted to 100 ml with water. 10 ml aliquot
diluted to 50 ml with water used to prepare standard addition plot by extracting samples with
ammonium pyrralidone diethyl dithiocarbamate in MIKB. Then trace metals back extracted into
5 ml mol I-I nitric acid