Analysis of Caffeine in Coffee

1. Analysis of Caffeine in Coffee Kate Penrod, Nikki DeLuca, Christina Robinson, and Jess Bases

2. Purpose • Quantify caffeine in brewed coffee • Varying strengths • Extract caffeine from grounds • Maxwell House: Regular and Decaf.

3. Background • Caffeine in food/drink • CNS stimulant • Schedule V drug • High levels • Restlessness • Irritability • Headaches • Heart complications

4. Methods • HPLC • Liquid • Separation • Liquid • IR • Solid and liquid • SFE • Solid • UV/Vis • Disabled

5. HPLC • Hypothesis • Samples • 10-50ppm caffeine standards • Strong caffeinated/decaffeinated • Regular caffeinated/decaffeinated • Weak caffeinated/decaffeinated • Dilution of coffee samples

8. Organic Separation • Sample Preparation (Dr. Peterman’s Coffeemaker) • Regular Caffeinated/ Decaffeinated • 1 Tbsp. grounds, ¾ cup water • Strong Caffeinated/ Decaffeinated • 3/2 Tbsp. grounds, ¾ cup water • Weak Caffeinated/ Decaffeinated • ½ Tbsp. grounds, ¾ cup water

9. Organic Separation • First Method • Adapted from Dr. Halligan’s Organic I Lab Manual • Extraction of Caffeine using Dichloromethane • Large emulsion layer, not a clear separation

10. Organic Separation • Revised Method • Added Na2CO3 which increased • caffeine’s solubility in aqueous layer • Separation layer more pronounced • Dried with Anhydrous MgSO4 • Vacuum under reduced pressure

11. Mass Quantification

12. Extracted Caffeine IR Characterization Substituted Alkene

13. Extracted Caffeine IR Characterization O – H stretch C = O C = N C = O CH3 C - N C = N Substituted Alkene Substituted Alkene Strong Decaff Weak Decaff C = O O – H stretch C = N Substituted Alkene Regular Decaff

14. Extracted Caffeine IR Characterization O – H stretch O – H stretch C = O CH3 C = N C - N CH3 C = O C - N C = N Substituted Alkene Substituted Alkene C = N O – H stretch C - N CH3 Strong Caffeinated Regular Caffeinated Substituted Alkene Weak Caffeinated

15. The Devil’s Instrument a.k.a. SFE

16. The Devil’s Instrument a.k.a. SFE • 4 Samples • “Pure” coffee grounds • Post brewing coffee grounds • 1 gram of each sample • 10 minute runs • End mass indications • IR results

17. SFE Data

18. SFE Extraction IR Analysis

19. UV/Vis • Attempted to use the DRA-600 • Solid Analysis • Missing part! • Call EVERYONE • Manufacturer • Distributor • Delivery Guy • Piece was backordered until May 20th • Put on hold INDEFINITELY.

20. Sources of Error • Organic Method • Impure caffeine for mass quanitification • Transfer between different glassware • Incomplete drying in extraction (O-H stretch peak) • HPLC • Day 1: Low pressure, purge lines • Day 2: Invalid date/time error, inconsistent • Day 3: Consistent results, ran all samples

21. Sources of Error (Part 2) • SFE • Leaks in the line • Issues with the amount of sample • Needed constant supervision • UV/Vis • Missing part • Phone tag • Wasted 2 whole lab periods

22. Sources of Error (Part 3) Jerry Sainsbury – Sales Representative Thermo Fisher Scientific

23. Conclusions • HPLC: • Strong decaf. was comparable to weak caf. • Weak and regular brews – 4:1 caf. vs. decaf. • Strong brew – 5:2 caf. vs. decaf. • Organic Method: • Qualitative data • Erroneous quantitative data • Masses very similar • SFE: • Low percent yields • Higher yield from decaf • Did not extract pure caffeine • May be caffeine plus side products • If UV/Vis hadn’t been in the initial method, further research would have been conducted

24. Further Research • Organic Method • Develop a new or revised method to extract pure caffeine in its solid form as was done in Dr. Halligan’s Organic I Lab • IR • Analyze liquid only • Create calibration curve • HPLC • Compare different coffee makers and brands

25. Further Research (Part 2) • SFE • Brew remaining grounds, analyze with HPLC • Determine other components of extracted grounds • UV/Vis • Obtain calibration disc and sample holder • Develop SOP for DRA-600