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Experiments Overview

Atomic absorption
Determination of Pb, Cu, and Zn in the environment

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Equipment:
AA spectrophotometer, Dri-block heater, Bottle-top dispensette, Oven set at 130°C.

Apparatus:
100ml vol. flasks, boiling tubes, funnels, funnel racks, filter paper, mortar and pestle, analytical sieves 90 to 100um; 1ml, 2ml, and 5ml grad.pipettes.

Sample:
Roadside dust. (0.5g) or Paint scrapings (0.10g.)

Solutions preparations:

1. 1000ppm Pb - dissolve 1.5980g Pb(NO3)2 in 1 liter distilled water.
2. 1000ppm Cu - dissolve 3.798g Cu(NO3)2.3H2O in 1 liter distilled water.
3. 1000ppm Zn - dissolve 1.0g metal in 30ml of 5M HCl and make up to 1 liter with distilled water.
4. 100ppm standards - dilute the 1000ppm 1 in 10.
ie 10mls in 100ml vol. = 100ppm.

Sample preparation:

1. Dry sample in oven at 130° C for 10 to 12 hrs.
2. Grind sample, sift through 100um sieve, and weigh out req. amt.
3. Predigest sample with 10mls conc. HNO3 overnight.
4. Digest on dri-block heater at 130° C for 2 to 3 hrs.
5. Filter through Watman filter paper #1 into 100ml vol. flask and make up to mark with distilled water.

Analytical notes:

1. Make up a mixed standard.
2. Possible range of standards required: Low range stds. and High range stds.

(1) 0.5, 1.0, 2.0, 4.0, 8.0 ppm.
(2) 0.25, 0.5, 1.0, 1.5, 2.0 ppm.
(3) 0.125, 0.25, 0.50, 1.0, 2.0 ppm.
(4) 2.5, 5.0, 10, 20, 30, 40 ppm.
(5) 5, 10, 20, 40, 60 ppm.


Operation of Instrument:

Follow User guide or get help from Technician or Demonstrator/Lecturer.



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