Introduction to Analytical Science | My Assignment Tutor

2nd AssessmentIntroduction to Analytical ScienceSubmission deadline: Thursday 29th April, 12:00 pm noon (UK time)There are three part in this exam you must answer questions in all three parts, in part B you havethe choice between two questions. Part A & B questions are worth 25 marks and the mini report inpart C is worth 50 marks.Part AQuestion 1 (must be answered) (25 marks)Explain where, when and why samples for analysis would have to be taken in a pharmaceuticalprocess where raw ingredients are bought in and processed into an active pharmaceuticalingredient. The active pharmaceutical ingredient is then mixed with excipients and formed intotablets. You should also discuss how representative samples could be obtained.Part BYou can choose to answer question 2a or 2b (25 marks)Question 2a (25 marks)Haloperidol is a typical antipsychotic medication. Haloperidol is used in the treatment ofschizophrenia, tics in Tourette syndrome, mania in bipolar disorder, delirium, agitation, acutepsychosis, and hallucinations in alcohol withdrawal. The chemical structure of haloperidol is reportedbelow.Exp log P = 4.3, pKa = 8.66OFNOHClWalter and colleagues ( developed a HPLC/UVmethod for the quantitation of haloperidol and other neuroleptics in human serum based on thefollowing:Serum (1 ml) was mixed in a 10-ml glass tube with the internal standard prochlorperazine (10 ng,dissolved in methanol) and 50 µl saturated solution of sodium carbonate. Seven ml of diethyl ether:nheptane (50:50, v / v) was added and the tubes were shaken for 30 min. After 10 min centrifugation at4000 g, the organic phase was transferred into a 10-ml glass tube and evaporated to dryness in aSpeed-vac concentrator (50 °C). The aqueous phase was extracted again, and this extract wascombined with the first dried extract and evaporated to dryness. After reconstitution in 100 µl of themobile phase, 75 µl was injected onto the chromatographic system.Moreover, the authors claim a 71.5% of average recovery.Please address the following questions:1 Why was sodium carbonate added to the sample (5.0 points)?2. What is the role of the 50:50 v/v diethyl ether:n-heptane solution in the samplepreparation (2.5 points)?3. Why was the aqueous phase extracted twice (2.5 points)?4. Was the sample pre-concentrated and if so by how many times? What are theimplications of this in the analysis (5.0 points)?5. The human serum #21 was run in liquid chromatography and a peak at rt ofhaloperidol provided a signal equal to 15000 mAu. Quantify the true mass ofhaloperidol which was present in the original volume by using the calibration curvebelow. Explain your reasoning (10 points).y = 85.517x + 215.58R² = 0.998705000100001500020000250000 50 100 150 200 250 300Signal (mAu)Concentration (ng mL-1)Haloperidol in human serumQuestion 2b (25 marks)Spectrophotometric technique exam question:Q1The following reaction is performed in a lab and you are asked to characterize the product accordingto the given information. While the reactants are liquid, the product is instead in solid state at roomtemperature once dried. When dissolved, it confers a pH equal to 2 to the water.IR spectrum of the reactantIR spectrum of the product1. KMnO4OHheat2.H20?MS spectrum of the reactantMS spectrum of the productQuestions What do the IR bands between 3200 and 2800 cm-1 refer to and why did theydisappear in the product? (9 points) What does m/z in these spectra represent and why some peaks are in commonbetween the reagent and the unknown? (9 points) What would have the spectra looked like if the ionization source was APCI ratherthan electronic impact and why? (3 points) What is the chemical identity of the product? (4 points)Part CQuestion 3 Mini lab report (50 marks)The following protocol is used to determine the purity after synthesised aspirin:1. Add the aspirin (product) to a weigh boat until a weight of 1.5 g is achieved.2. Transfer the aspirin to a 250 mL conical flask then add 25 mL of NaOH.3. Add 25 mL of the water to this preparation.4. Add a stirring bar to the conical flask then place it onto a hotplate. Bring mixture to asimmer and hold it there for 30 minutes.5. Remove flask from hotplate and allow to cool.6. Once cooled, transfer all the conical flask contents into a 250 mL volumetric flask.7. Rinse the flask using a Pasteur pipette and deionised water to ensure all contents areremoved. Use deionised water and a Pasteur pipette to top the liquid level up to thecalibration mark on the volumetric flask.8. Place a stopper into the flask and invert several times to ensure full mixing of thecontents.9. Carefully fill the burette up to the calibration mark with sulfuric acid.10. Pour 50 mL of the volumetric flask contents into a beaker11. Pipette 25 mL of this solution into a 100 mL conical flask.12. Add 4 drops of the phenolphthalein indicator to the flask and swirl to mix.13. Titrate slowly and carefully until the end point of the titration is achieved (thephenolphthalein pH indicator will change from pink to clear).14. Repeat titrations (at least 4 times).When the endpoint was determined for 4 titrations the following volumes of sulfuric acid were used:1. 9.60 mL2. 9.45 mL3. 9.50 mL4. 9.40 mLWrite a mini report (2-3 page) using the standard structure of a lab report, see next page.When using references in the Introduction section you must use the APA referencing method, seeMoodle.Aims (2 marks). Provide a clear statement of the aims for the experiment being performed.Introduction (10 marks). Include a brief introduction to the experiment that is performed. This shouldinclude a brief pharmaceutical and chemical background part and anoverview of the used method and why this particular method is used(chemical formulae can be included, a free chemical structure drawingprogram is available via Moodle).Methods (0 marks). Can be excluded here as provided in the exam. Simply state “see examscript”.Results (15 marks). Include the provided data. Perform the analysis (include your calculations). What is the confidence interval of your result?Discussion (20 marks). What is the result of the titration experiment? Given the task what can you say about the performed analysis and thepurity of the product. What possible errors related to this experiment may have occurred?Conclusion (3 marks). A concise statement summarising the experiment and its outcome (takehome message).


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