Question

Describe an experiment in which you could find the identity of an unknown metal.

Answer 1

Answer:

Determination of lead in river waters by Atomic Absorption Spectrometry of the flame.

Explanation:

1 L of river sample was taken at an edge distance of 1.5 m and a depth of 30 cm, collected polyethylene bottles.

They were filtered through 0.45 µm depolidivinildifluoride syringe filters (pore size) and acidified with 1% v / v HNO3 until a pH less than 2 (pH = 1.85) was obtained, to reduce the interference by organic matter, and convert all metal to a free form determinable by Atomic Absorption Spectrometry (AAS) of the flame.

Flow Injection Analysis System (FIA) The flow injection analysis system (FIA) for lead preconcentration and detection in river water samples by AAS

A minicolumn of nylon and polycarbonate with teflon connections was used, whose dimensions are: 5.5 cm in length and 5.0 mm in internal diameter.

The filling material used was: TSK, consisting of azo-immobilized 8-hydroxyquinoline (bonded) to the “Toyopearl TSK” HW –75F vinyl copolymer with particle size: 60 –100 mesh.

When reading the real samples by ASA with direct fogging in the flame, absorbance values ​​were obtained as a result of the method error interval (background noise), so that the lead concentration is below the measurement detection limit of the instrument ASA (0.1 mg / L); therefore, the use of preconcentration methods is required to improve the sensitivity of the determinations.