46
River and Stream Sediments
Time (minutes)
3
5
8
10
200,---~1~--~1---------------~1----~----~
~---160
/
~ 120 (
Conditions
!!!
450W Power
~
3 vessels
c:
/
20 mL 1:1 HN03:H20
~
HN03. 70 wt. %
~ :/
a
0
0
20
40
60
80
100
120
Pressure (PSIG)
Time (minutes)
10
20
30
160
.....---120
."
Conditions
!!!
/
3 vessels
~ 80
_,_
10 mL 1:1 HN03:H20
2l.
5 mL wt. % HN03
~ . . , 1..3 mL wl "H,O,
180 watts _I
300 watts
b
w/ .... // .... /// .... ;';;/////////////////////////////////////////d
04----r--~----r---~---r---r---,--~
o
10
20
Pressure (PSIG)
30
40
Fig. 2.7 a, b
Microwave digestion of NBS 1645 standard river sediment with; a 1;1 nitric acid; b
nitric acid-hydrogen peroxide (from [57]).