Physico- Chemical Methods

Páginas: 2 (286 palabras) Publicado: 18 de abril de 2012
Questions for 2nd practical – Physico-chemical methods:

1. Define Lambert-Beer law and explain used symbols
- A= ε*d*c
- Absorbance A, e is molar absorption coefficient, d islayer thickness and c concentration
2. Graphically express general analytical (calibration) curve and explain values on axis X and Y
- [pic]
3. Define principle of centrifugation- Centrifugation is a physical method of separation of solid or liquid particles with differing densities by action of centrifugal force. It is carried out in centrifuges.
4. Defineterms – sediment and supernatant in relation to centrifugation. Expalin on the figure below:

- Sediment is the fraction that has settled down on the bottom of the cuvetteduring centrifugation, the liquid above is the supernatant

5. Define shortly term „dialysis“
- Dialysis is a method of separation of components of a homogenous or colloid solutionbased on size of molecules. By dialysis, macromolecular compounds can be separated from low molecular weight ones. Small ions and molecules can permeate through a semipermeable membrane because ofthe difference in osmotic pressure of the dialyzed fluid and of the pure solvent. Concentration gradient is the driving force.

6. Write the formula for the calculation of unknown sampleconcentration (Cunknown) from its absorbace (A unknown) and absorbance (Ast) and concentration (Cst) of standard solution

Cunknown = ––––––––––( Aunknown/Aknown)*Cknown

7. Write the formula for the calculation of concentration from Lambert-Beer law
8. What ion can be determined by reagent bathophenanthroline: Na+, Cl- , Fe2+, P5+, Mg2+
9. Whatis physiological value of iron ion in µmol/l in serum in male (men)? 14,3-26 µmol/l
10. What is physiological value of iron ion in µmol/l in serum in female (women)? 10,7-21,7 µmol/l
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