DANIELLE TAGUE KHADIJA MITCHELL Real World Project: Using HPLC and SFE to determine amounts of caffeine in different coffee samples

Purpose Determination of the amount of caffeine in decaf and caffeinated ground coffee and coffee beans was done using HPLC. Extraction of caffeine from each sample was done by SFE. The amounts of caffeine determined using HPLC were compared with the amounts of caffeine extracted using SFE.

Data: SFE Decaff BeanCaff BeanGround Decaff Ground Caff Mass before1.0079g1.0020g1.0060g1.0023g Mass Caff extracted.0930g.1551g.0721g.0201g Mass sample left over.9147g.8466g.9337g.9282g We weighed the flasks before and after the extraction and took the differences to determine amounts extracted. The ground caffeinated coffee sample did not yield results we would have expected – if any caffeine was extracted at all it was a very minimal amount. The other samples showed results we expected, low amounts of caffeine in decaf samples and a higher amount in the caffeinated sample.

Data: HPLC From Original Samples Decaff BeanCaff BeanGround Decaff Ground Caff Mass in 50 mL distilled water mg50.04 mg50.0 mg50.04 mg Dissolved 50 mg samples in 50 mL distilled water over heat. Bean samples did not completely dissolve

Original Samples SampleConcentration (ppm) Ground Caffeinated Ground Decaffeinated Bean Caffeinated82.72 Bean Decaffeinated28.27 Concentration of caffeine in the ground decaff sample was lower than caffeinated as expected Concentrations in the beans were low (due to difficulty in dissolving beans)

Data: HPLC From SFE Decaff BeanCaff BeanGround Decaff Ground Caff Mass in 50 mL distilled water 51.7 mg50.6 mg50.5 mg50.4 mg Left over sample from SFE, 50 mg, was dissolved in 50 mL distilled water. Bean samples did not completely dissolve. Caffeine extract was dissolved in 50 mL distilled water. (methanol or chloroform)

Samples from SFE SampleConcentration (ppm) Ground Caffeinated Ground Decaffeinated Bean Caffeinated37.77 Bean Decaffeinated21.13 Ground Caff ExtractInconclusive Ground Decaff ExtractInconclusive Bean Caff ExtractInconclusive Bean Decaff Extract3.22 The values of the two ground samples were too close Bean samples were low because it was hard to dissolve Inconclusive and low data for the extracted caffeine because it was not able to be dissolved.

Conclusion of Results Caffeinated samples were higher as expected Decaff was not as low as expected Bean samples were not reliable because they didn’t dissolve completely – but caffeinated beans still had higher results Extracted caffeine was also useless because it did not dissolve and results were inconclusive The left over samples from SFE should have been lower since the caffeine was extracted from them

Error Our extracted caffeine should have been dissolved in either methanol or chloroform rather than water We did not initially do this to be consistent with other samples We could have reran the samples through the SFE again to attempt to extract more but we ran out of time