You also want an ePaper? Increase the reach of your titles
YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.
Flameless: 0.000 I mgll (solution)<br />
B. Reagents<br />
Chelating reagent: ammonium pyrrolidinedithiocarbamate (APDC) or sodium diethyldithiocarbamate<br />
(DEDC). Make up a 5% solution with deionized-distilled water. Extract at least twice with methyl<br />
isobutyl ketone (MlBK).<br />
Methyl isobutyl ketone (MIBK) (distilled).<br />
C. Extraction<br />
(I) Place 100 ml of solution in a 250-ml acid-washed separatory funnel. Add 2 ml of chelating<br />
reagent and add 5 ml ofMIBK.<br />
(2) Shake thorough Iy for about 3 min and save the upper (extract) layer for analysis.<br />
D. Analysis<br />
For flame conditions, adjust the spectrometer settings as above. It may be necessary if the metal<br />
concentrations are very low to use the flameless attachment of the atomic absorption spectrometer. Check<br />
manufacturer's handbook.<br />
6.7 Lead (Atomic Absorption)<br />
I. Concentrations<br />
Average river water 1-10 fLg11<br />
Average nearshore sediment 20 mg/kg<br />
Sea water"" 0.02 - 0.1 fLg11<br />
The dissolved sediment as prepared in Section 6.2 is analyzed by flame atomic absorption with the<br />
following operating parameters:<br />
A. Detection Limits<br />
Flame: 0.05 mgll (solution) ( = 50 mg/kg in sediment)<br />
B. Working Range<br />
Linear response can be expected from the spectrometer up to 20 mgll (solution) (=20 mg/ kg in<br />
sediment).<br />
C. Interferences<br />
No serious chemical interferences. Background corrector is highly advantageous.<br />
D. Instrument Parameters<br />
Wavelength: 283.3 nm<br />
Fuel: air I acetylene<br />
Check manufacturer's handbook<br />
Flame: oxidizing (lean. blue)<br />
II. Solvent Extraction<br />
This method is necessary for the low concentrations found in seawater.<br />
A. Detection Limits<br />
Flameless: 0.00002 mgll(solution)<br />
35
Change language