Analgesic Recovery

Calculations Required:

* Percent Recovery:

Mass of analgesic obtainedMass of analgesic specified x 100%

Analgesic obtained: 206.6 mg

Analgesic Specified: 400 mg

% Recovery: 206.6 mg400.0 mgx 100.0 %=51.65 %

Lab Discussion and Results

The purpose of this lab is for students to become familiar with different lab techniques introduced in the Lab Manual and at the Pre-Lab lecture hall. It is to promote the students ability to be prepared for future labs to come that may require certain techniques to be executed.

The goal of this particular lab was to extract the active ingredient, analgesic, in the drug by dissolving ibuprofen into methanol. When done precisely, the percent recovery should be 100% and the melting point should be similar to the published values in the Lab Manual. The purpose of percent recovery measures how accurately the lab was executed and the melting point determines the purity of the analgesic drug obtained from the ibuprofen. In this lab, the percent return was 51.65%. Even though the results are expected to be less than 100% return, the result was relatively low as there was only about half of the analgesic remaining in the return product. Possible occurrences that could have altered the desired results include errors that would have happened during the lab procedure. Examples of such include that of inaccurate measurements, insufficiently transferring the crushed ibuprofen from one container to another, and unable to completely remove the analgesic after purification. One significant aspect regarding errors was the evaporation of the methanol with the air; the pressurized air was forceful enough to send the methanol/analgesic mixture out of the container and into the hood. Even though I had used a relatively larger container than the conical vial to prevent the splashing, I hadn’t realized the pressure of the air was so forceful that the larger container made little difference. For future references, it would probably be wise...