Adulterated Herb Lab
Experiment 8: Identification of an Adulterated Herb
The purpose of this lab is to analyze the volatile oils of some herbs through TLC testing and then identify the adulterant in a sample.
Unfortunately, we ran out of time to complete the lab; however, we were able to get through most of it, and were only missing the adulterant. The first step to identify our unknown samples was to create TLC plates that should results with each known compound and 95% hexane: 5% ethyl acetate, 90% hexane: 10% ethyl acetate, or 80% hexane: 20% ethyl acetate. Each student was designated one of these concentrations of solvent as well as visualization method. After we tested and calculated the Rf values of each of the following known compounds with each concentration: anise, caraway, cinnamon, cloves, coriander, and cumin. When all the known compounds were tested only the two first compounds reacted with DNPH and that’s because aldehydes tend to react faster with DNPH. …show more content…
My group had the unknown samples numbered 521, 522, 523, and 524. We prepared each sample with the hexane extract, so that when we spotted each sample on the TLC plate it would give us accurate results. We then compared the Rf of these plates to previous Rf’s as well as the odors from the chemical to identify every compound. Since our sample 521, reacted both DNPH when tested we concluded that it would be an aldehyde which narrowed our choices. We then compared the Rf values of each sample and concluded that our samples with respective to their number were the following: caraway, cloves, and coriander. We noticed that both sample 521 and 524 reacted with DNPH and had similar Rf values, meaning that within sample 524, there must be some caraway. Unfortunately, like I stated before we weren’t able to finish the lab and we never got to do plate number
The purpose of this lab is to analyze the volatile oils of some herbs through TLC testing and then identify the adulterant in a sample.
Unfortunately, we ran out of time to complete the lab; however, we were able to get through most of it, and were only missing the adulterant. The first step to identify our unknown samples was to create TLC plates that should results with each known compound and 95% hexane: 5% ethyl acetate, 90% hexane: 10% ethyl acetate, or 80% hexane: 20% ethyl acetate. Each student was designated one of these concentrations of solvent as well as visualization method. After we tested and calculated the Rf values of each of the following known compounds with each concentration: anise, caraway, cinnamon, cloves, coriander, and cumin. When all the known compounds were tested only the two first compounds reacted with DNPH and that’s because aldehydes tend to react faster with DNPH. …show more content…
My group had the unknown samples numbered 521, 522, 523, and 524. We prepared each sample with the hexane extract, so that when we spotted each sample on the TLC plate it would give us accurate results. We then compared the Rf of these plates to previous Rf’s as well as the odors from the chemical to identify every compound. Since our sample 521, reacted both DNPH when tested we concluded that it would be an aldehyde which narrowed our choices. We then compared the Rf values of each sample and concluded that our samples with respective to their number were the following: caraway, cloves, and coriander. We noticed that both sample 521 and 524 reacted with DNPH and had similar Rf values, meaning that within sample 524, there must be some caraway. Unfortunately, like I stated before we weren’t able to finish the lab and we never got to do plate number