The importance of chemical composition. Nice job on the group suggestions. Key points are

1. Things only behave the way they are supposed to if they have the correct chemical composition.

2. The manufacure of most things requires monitoring of the chemical composition of starting materials, intermediates and final products.

3. When things go wrong, often information about the chemical composition of relevant materials can help sort out (a) what has happened and (b) how it might be fixed.

4. Answering the question "Is it safe?" often requires information about chemical composition of whatever "it" might be.

5. Every contact leaves a trace. This is a key feature of chemical analysis in support of crime detection.

6. The progress of many scientific disciplines and the practice of many are underpinned by the provision of reliable information about chemical composition.

Click here for some more information about the same topic. Pictures taken from a paperback I wrote a few years ago (I think there is a copy in the library).

What to ask the client. There are some really basic questions to ask first such as

Why do you want to know? What will you do with the results?

Then ask about the chemical species involved.

What are the analytes? What is the matrix?

Ask about expected concentrations. What is the likely concentration of the analyte?

Then ask about performance requirements. What precision and accuracy are needed?

Then ask. How much sample is available? Do you want it/them back?

Then ask. How many samples do you have? When will they arrrive? How quickly do you want the answers?

Don't forget to establish Who will be taking the samples?

Key Points.

If the sample is not representative of the bulk material from which it is taken, then the analysis is not useful. If the answer that is provided does not come with some estimate of the uncertainty, then the analysis is not useful. The uncertainty is often expressed as a ± value.