Heparin is used as an anti-coagulant. A risk of heparin use is thrombocytopenia, or low platelet count. This risk is minimized with the use of low molecular weight heparins (LMWH), therefore it is desirable to separate LMWH from higher molecular weight heparins. The method of choice to do this is molecular exclusion chromatography. Below is a chromatogram from a molecular exclusion chromatographic run. Peaks ranging from A to J are clearly distinguishable. The heparin mixture that was analyzed had anywhere from 6 to 30 repeat units of monomer (where the heparin with 30 repeat units would be roughly five times the size of the heparin with six repeat units). a. Which letter most likely represents the peak with 6 repeat units given these heparin polymers were separated with molecular exclusion chromatography? b. Explain your reasoning describing the mechanism of retention in molecular exclusion chromatography. 100 80 60 60 Relative Abundance 40 40 E GH 20 20 B A 36 38 40 42 44 46 48 50 50 52 2 54 56 58 60 axis label on bottom is retention time (minutes) 60

Iman has a mixture of two compounds A and B. A is a protein, and B is a lipid. He plans to separate the mixture using a column chromatography technique. He packed the column with amino bonded with siloxane material and use a mixture of 20:80 of water: hexane as the mobile phase. i) Sketch the apparatus set up for the chromatographic technique used by Iman. Use the correct chromatographic terminologies to label all of the apparatus, materials, and phases. ii) Predict the sequence of elution when the mixture was loaded onto the separation column. Justify your answer. iii) After the first compound was eluted, Iman discovered that the second compound was taking too long to pass through the column. Please suggest any strategies that could be used to aid the elution process.

Please propose a chromatography-based strategy to purify human insulin proteins that have been expressed in bacterial cells.

Column Chromatography Alumina Chromatography Mixture 9:1 Hexanes:Ether 8:2 Hexanes:Ether 1:1 Hexanes:Acetone Amount Used 3.962 g 0.143 g 9.50 mL 9.50 mL 11.00 mL Additional Observations (Color, etc.) BIU X₂ X² → BI IU X₂ X² → BI IU X₂ X² → BI IU X₂ X² → BIU X₂ X² →

Please answer both. Thank you.

What is 4a?

Can you answer first 2 questions

1) Study the chromatograph (below) of a mixture of Compounds A and B, run on the GCs in the teaching labs at CU Boulder. Compound A has the shorter retention time. STAAT 61 1.11 227 RT TYPE AREA XXXX XXXX XXXX AREAS 0.009 55874 44.117 ARIHT 0.61 XX XX XX 1.11 2.27 XX XX XX TOTAL AREA=XX MUL FACTOR=XX 1. What is the retention time of compound A? Compound B? 2. Which compound is present in a larger amount? 3. Which compound has the lower boiling point? 4. What would happen to the retention times of compounds A and B if the column temperature were raised? 5. You suspect that compound B is octane. What can you do to provide supporting evidence for this hypothesis?

Which of the following types of liquid chromatography uses immobilized biochemical as a stationary phase? affinity chromatography ion exchange chromatography gel permeation chromatography exclusion chromatography

In molecular exclusion (size exclusion) chromatography, the molecules have the longest retention times. a) the larger molecules b) the smaller molecules