Intro chromatography_printPDF

• newEditor
• Scheikunde
• Middelbare school
• havo, vwo
• Leerjaar 3

-What is

-What is chromatography

-How to use it to separate mixtures

-How to separate ink

Paper chromatography

• Apply a small amount of mixture to the bottom of the paper

• Stand the paper upright in the solvent

• The solvent 'travels' up through the paper, carrying some substances from the mixture upwards

• mobile phase = liquid

• 
  

stationaire fase = papier

Paper chromatography

mobile phase

paper chromatography

base line

Retention factor (Rf)

• Identify substances using Rf value

• Each substance has its own Rf value at the same temperature, stationary phase, and solvent

• To calculate the Rf value, the distance of the substance (A) and the distance of the solvent (B) are needed

Rf-value

1. distance between startpoint en middle point of spot substance(A) 

2. Distance between startpoint and endpoint of the mobile phase (B) 

3. Rf-value = A / B.

Assignment

Calculate the Rf value of the

dark pink spot

Rf=A/B

Assignement

Calculate the Rf value of the

dark pink spot

 Rf-waarde =    A  / B   
                        = 8,5 / 10 = 0,85

How to separate ink with chromatography=> see worksheet