CHEM1057 Analytical Challenge - 2025
The first assessment task for CHEM1057 will require the completion of a report on an analytical challenge problem. For the challenge, which you have been set, you will need to answer a set of questions and prepare a report of no more than four A4 sides in length.
Note that in answering these questions; you are encouraged to do some research, looking for published studies and/or spectra as appropriate. Whilst using ‘Google’ can get you some way in your research, you should find using chemspider.com, chemicalbook.com, the NIST chemistry webbook, Sci-Finder N, and wok.mimas.ac.uk more useful. You should provide references to any papers or websites to which you may refer to in your report. A reference manager (Mendeley or Endnote etc.) can be useful in managing your references. The references do not contribute to the page count.
The report needs to be submitted through e-assignments by the deadline published on BlackBoard. Note, late penalties will apply and high standards of academic integrity are expected. Early submissions are encouraged.
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Marking criteria
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Out of
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Marks
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Chemical structure and physical properties of target analytes
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24
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Please provide a table of the chemical structures of the target molecules (drawn in ChemDraw) and any relevant physical properties that are necessary to evaluate the use of the analytical techniques.
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Evaluation of 4 classes of analytical techniques
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40
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For each of the 5 classes of analytical technique (chromatography, infrared , UV- Vis, NMR spectroscopy, and mass spectrometry) explain how the technique may be used in a qualitative and/or quantitative analysis to determine the presence of the target analytes, highlighting any key parameters and spectral features, as appropriate. You may wish to include sample spectra.
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Met the specific challenge question asked
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16
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Make a recommendation as to the most appropriate method or methods of analysis so as to meet the challenge posed, including recommended samples handling or processing.
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Use of references and their attribution
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10
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Correctly presented references from the primary scientific literature, books, or databases/websites. Consistent use of reference style.
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Quality of presentation - completed to a professional level
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10
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Layout of report, correct use of scientific terminology, correct grammar and spelling, use of a professional writing style.
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Analytical Challenge Problem 3.
Quality Control of Green Teas
Tea is the most widely consumed drink in the world and consists of three major types: green tea (unfermented), oolong tea (semi-fermented), and black tea (fermented). Green tea contains a variety of products such as polyphenols, caffeine, theanine, and vitamins1,2 .
Many characteristics are considered for judgement of the tea quality, and this is reflected in the price of the tea. The quality of a green tea is mainly assessed through its colour, flavour, and aroma and depends on the content of several compounds.
A local tea green tea importer is concerned about the grading of the tea purchased from a new supplier and suspects that they are not of the quality reported. The importer has employed you to analyse the green tea samples, and you are tasked with determining suitable analytical methods for the six compounds listed caffeine, theobromine, gallic acid, epigallocatechin gallate, epicatechin-3-O gallate and epicatechin.
To answer the client’s brief, you will need to confirm which of these compounds is present in the imported teas and identify suitable analytical methods for the quantification of the key marker molecules listed above. In your report, provide a chemical structure and any physical properties that would be important in selecting the analytical methods.
For each of the analytical techniques available to you, listed below, determine whether the method is an appropriate choice to provide the analysis of the green tea samples. In each case, justify your answer. You must complete this for all of the techniques, not just
your preferred method(s).
a. Chromatography (explaining the most appropriate method for the sample or samples of interest)
b. Infrared spectroscopy
c. UV-Vis spectroscopy
d. NMR spectroscopy
e. Mass Spectrometry
After selecting the most appropriate analytical technique (or combination of techniques) describe the factors you would need to consider when preparing samples of the green tea for analysis.
References
1. K-H. Choi, J.S. Park, H.S. Kim, Y.H. Choi, J.H. Jeon, J-H. Lee. J. Korean Magn. Reson. Soc. 2017, 21, 119-125
2. Z. Han, M. Wen, H. Zhang, L. Zhang, X. Wan, C-T, Ho. Food Chem. 2022, 374, 131796.