Question

Good Afternoon,

I am doing a laboratory report for the course entitled: Principles of Instrumental Analysis. It is a 4th year course and i have been tasked with the following analytical problem, "Determine the DEET composition in common bug sprays." In other words, I have to determine the concentration of DEET in a couple of bug sprays. The sprays and DEET are supplied. Secondly, I have to prepare a protocol for measuring the concentration of DEET in my samples and a GC:MS method for analysis of DEET. By the way, GC:MS is short for 'Gas chromatography–mass spectrometry' and as you may know it is an analytical method that combines the features of gas-chromatography and mass spectrometry to identify different substances within a test sample. Basically, I need your help in giving me a layed-out protocol (such as we would see in a manual) of what I will do in the lab to answer the above analytical problem. You can think of it as a lab manual that you would write so that someone else could go in the lab and perform the experiment in your place.

It should have all of these components.

1. Brief (!) introduction of the problem (1 short paragraph)

2. Sampling – how much (be precise), in what form, how many, where, etc.

3. Sample preparation – list all reagents needed up front. Then list all steps and procedures you will use to prepare the samples for instrumental analysis. You should know what concentration ranges you are aiming for.

4. Standards preparation – list steps involved in preparing your standards used for calibration (if you need to do this).

5. Instrumental Analysis – list the procedure for running the instrument, including any blanks, standards. The sequence of runs (sample, standard, blank, etc) should be listed.

6. Data Analysis – how will you go from the raw data provided by the instrument to a value with a ± deviation on it.

Please refer to the above question. Can you give me a detailed layout of how I will determine the concentration of DEET in my samples before doing the GC:MS analysis? You do not need to determine the composition or synthesize DEET. You need to determine the concentration of DEET, in a couple of bug sprays. The sprays and DEET are supplied.

I'm not quite understanding. Thank you for your clarification once again.