DRAFT: This module has unpublished changes.

Introduction:

The goal of this experiment is to learn how to properly separate multiple components that are in a solution via the process of liquid chromatography. (that is, running the components through a non-polar matrix, while using a slightly polar solution, called the eluent, through, so that the polar molecules will be carried through the matrix faster than the non-polar molecules, which will bond to the matrix and thus be slowed.)

I hypothesize that by measuring the amount of eluent between the start and end of the first compound, and the start and end of the second compound, that we should be able to calculate the difference in separation between the mobile and stationary stages, and the resolution of the column used.

 

Equipment:

  • Sep-Pack, (single)
  • Sep-Pack, (triple)
  • Syringe, 1-mL
  • Syringe, 10-mL
  • Graduated Cylinder, 10-ml
  • 18% Isopropanol, 100 mL
  • 800g weight
  • Unsweetened Kool-aid® drink, 10 mL
  • Deionized Water
  • Stand, with vise

 

Method:

  • Gathered Equipment, assembled stand with vise, prepared unsweetened Kool-aid® drink according to directions from TA.
  • Used 10-mL syringe to flush Sep-Pack with 10 mL 18% Isopropanol. Used vise and stand to stabilize syringe and Sep-Pack, 800g weight to ensure steady rate of flow, and graduated cylinder to collect the eluate and monitor the rate of flow.
  • Disposed of eluate in graduated cylinder. Cleaned cylinder.
  • Flushed Sep-Pack with 10 mL of deionized water.
  • Injected 1 mL sample of unsweetened Kool-aid® drink into Sep-Pack, using 1-mL syringe. 
  • Collected and discarded effluent that washed out while injecting the sample.
  • Filled 10 mL syringe with 18% Isopropanol, attached to sep pack, and mounted on stand using vise. Placed cleaned graduated cylinder beneath, to collect eluent.
  • Using weight to ensure even flow, pumped solvent through Sep-Pack, collecting eluent in the graduated cylinder below. 
  • Measured the shifts in dye color, as seen in table 2, recording how much eluent flowed through for each to begin, then end.
  • Repeated test with triple Sep-Pack.
  • Disposed of eluent according to directions from TA, cleaned all containers and syringes, and returned all equipment to its point of origin.

 

Data Analysis:

 

R (single Sep-Pack)= 0.46

R (triple Sep-Pack)= 0.67

 

Conclusion:

The goal of this experiment is to learn how to properly separate multiple components that are in a solution via the process of liquid chromatography. (that is, running the components through a non-polar matrix, while using a slightly polar solution, called the eluent, through, so that the polar molecules will be carried through the matrix faster than the non-polar molecules, which will bond to the matrix and thus be slowed.) By measuring the amount of eluent between the start and end of the first compound, and the start and end of the second compound, that it is possible to calculate the difference in separation between the mobile and stationary stages, and the resolution of the column used.

 

(Calculation of error not possible, due to lack of an accepted value.)

 

R (single Sep-Pack)= 0.46

R (triple Sep-Pack)= 0.67

 

Possible sources of error include:

Failure to properly measure the volume of liquid in containers. (Rendering further calculations inaccurate.)

Failure to apply steady pressure. (applying too much pressure may not give the compounds time to bond with the matrix, and thus give an inacurate reading.)

Human error is always in effect, given that the laboratory does not function under ideal conditions. As such, there is always the possibility of inaccuracies with measurement, perception of measurement, inaccuracies of equipment, and other such errors. (However, this is not likely to be the sole cause of the inaccuracies within this experiment, though it may contribute to it.)

 

Possible improvements that one could make to the experiment include using more accurate graduated cylinders, using more accurate syringes, using a more polar eluent, using a larger column, and repeating the tests more than once (to minimize the impact of an anomalous result).

DRAFT: This module has unpublished changes.