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Final Assessment

You have now completed the knowledge content and activities for TEST506A - Apply Spectrometric Techniques. You may undertake the assessment if you are ready or review the material in this unit again.

To be recognised as competent in this unit you must be assessed in both the knowledge content and the workplace skills. The assessment is in two parts, part one asks you to apply the knowledge you have acquired in the unit and part two is a practical assessment.

Part 1. Knowledge Assessment
This part of the assessment is divided into five sections.

Section 1 - Prepare for the Analytical Procedures

  1. How would you confirm the identity of a sample for analysis and how would you locate the standard method to be employed?

  2. Name three hazards associated with the use of gas cylinders in the laboratory.

  3. Sample condition is important for analysis. Name three potential problems arising from sample condition.

  4. Why is chain of custody of samples important?

  5. Sample preparation is also important for the subsequent analysis to be accurate. Use an example from your own experience and explain and detail each of the steps involved in the sample preparation. Be sure to explain why each of these steps is important and how incorrect preparation may affect the sample and the subsequent analysis.

Section 2 - Spectroscopic Concepts and Principles

  1. Give a brief explanation of spectroscopy.

  2. What are the two main uses of spectroscopy in chemical analysis?

  3. What is electromagnetic radiation (EMR) and what is it comprised of?

  4. What is Beer’s Law and why is it important?

  5. How are transmittance (T) and absorbance (A) related?

  6. If A = 0.3, what does T equal, and when T = 25%, what does A equal?

  7. A sample solution with a molar absorbency of 210 cm-1 mol-1 L gives an absorbence reading of 0.612 in a 1.0cm curette. What is the molar concentration of the analyte?


Section 3 - UV-Vis Spectroscopy

  1. What range of wavelength is UV and Visible light?

  2. How does an analyte absorb and emit energy in UV-Vis spectroscopy?

  3. What parameters affect UV-Vis absorption by an organic compound?

  4. In UV-Vis spectrophotometry what is the sample held in and what care needs to be taken to ensure correct readings?

  5. UV-Vis spectrophotometers come as single beam or dual beam designs. What is the major advantage of a dual beam design?

  6. Why is choice of solvent important in UV-Vis spectrophotometry and what wavelength would be the minimum that you could use for the following two sample solvents - acetone and diethyl ether?

  7. Beer’s Law describes the relationship between concentration and absorbance. What causes deviations from Beer’s Law?

Section 4 - Atomic Absorption Spectroscopy: A Scenario

You have been asked to determine the Pb level of the water run off sample that was used in Section 4 of this unit for Cu analysis.

  1. Explain how you would do this in general terms, i.e. explain the general method of flame AAS.

  2. Specify and list those flame AAS parameters that would need to be changed to perform this analysis.

  3. List any additional safety requirements for the analysis of Pb over those required for the analysis of Cu.

  4. After analysis you find that the concentration of Pb in the water run off is very low and you suspect that your measurements at this concentration are inaccurate. List two ways that you could use to overcome this problem. Note - one of the ways should be a change of equipment.

You will need to search the Internet, consult appropriate textbooks or other sources to answer the following questions.

  1. What flame type would you use for Pb analysis?

  2. In µg/mL, what are the working ranges for Cu and Pb for flame AAS analysis?

  3. In ng/mL, what are the working ranges for Cu and Pb graphite furnace AAS analysis?

  4. What are the advantages of the graphite furnace AAS over the flame AAS?

  5. What general laboratory safety precautions would you take when working with water run off containing unknown concentrations of Cu and Pb, as well as other possible contaminants.

Section 5 - Structural Elucidation

  1. What is structural elucidation?

  2. Briefly explain how a mass spectrometer (MS) works.

  3. What would be the detected masses of the following molecules in a mass spectrometer - C2H8N2, CH4, C4H8O3?

  4. Briefly explain how an infrared spectrophotometer (IR) works?

  5. Briefly explain how a nuclear magnetic resonance spectrometer (NMR) works?

  6. (a) Interpret the following NMR spectrum for ethanol by relating the features of the spectrum to the structure of the molecule. Mr = 46.0702

NMR spectrum for ethanol

(b) Interpret the following MS and IR data for ethanol by explaining how the information is related to the structure (or formula) of the molecule.

IR spectrum for ethanol


Mass spectrum of ethanol

  1. Determine the structure of the molecule based on the following MS, IR and NMR data.
    Mr = 88.1086

Mass spectrum

IR spectrum

NMR spectrum

Part 2. Practical Assessment

Practical assessment requires you to demonstrate the competency on-the-job (or in a simulated laboratory).

The assessment will consist of:

  • a demonstration of the competency in an on-the-job situation or a simulation
  • oral questioning about such things as laboratory specific knowledge of processes, troubleshooting and
  • questioning related to specific safety or other factors that may be peculiar to the learner's work environment
  • any relevant workplace documents that support the assessment.

If you are ready to undertake the practical assessment send a message to your tutor using the mail facility.

Use the following link to obtain a checklist to be used by your assessor.

You will need to successfully reach the required level of competency in all of the following items to complete this unit of work. The items listed below are the performance criteria by which you will be assessed.

Note: there are checklists for five (5) analytical techniques on the following pages. Use only those checklists that are appropriate for the analyses that you perform.

On successful completion you must have this Checklist signed by your supervisor.

Print these pages to obtain the Checklists for this unit.

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