(5) Methods and Their Scientific Basis

Question 1

How to ensure the method works?

Answer 1

1. basic understanding of how a method works
2. know your equipment
   » helps to more effectively perform analysis and interpret results

Question 2

Understanding the method helps to:

Answer 2

1. Professionally interpret the results
2. set up meaningful controls (-ve and +ve)
3. troubleshoot effectively if the method fails to produce good results
4. redesign the method to improve effectiveness
5. design new methods based on a current method to perform a different experiment

Question 3

Knowing your method: how (7)

Answer 3

1. summarise the method in a table
2. make a checklist of materials and equipment required
3. predict effect of altering components (property, not component itself) (helps with troubleshooting)
4. determine controls
5. determine standards
6. determine method limit

Question 4

What is a scientific method?

Answer 4

precisely defined protocol of materials and processes to produce specific kind of data
(recipe/steps of scientific approaches to take the sample and collect the data you are after)

Question 5

1. Summarising the method

Answer 5

• method may be complex so breaking it down into it’s simplest components can be useful to see how each part contributes to the method
• can use table/flowchart

Question 6

2. Checklist of materials and equipment

Answer 6

• list how it’s purposes and properties are related to the experiment

Question 7

3. Effect of altering components

Answer 7

• list what should happen to the results of the method if increase/decrease concentration, pH or other property
• think about the overall way the method works and how each component contributes
• understanding the effects of altering components helps troubleshooting

Question 8

4. Controls

Answer 8

• include in assay to test that it works properly
• positive controls test the whole system
• negative controls check for background activity

Question 9

5. Standards

Answer 9

• qualitative and quantitative

- allows you to compare results between different assays, run on different days or between different labs

Question 10

6. Method limits

Answer 10

• determine the detection of results using the standard plot to see the min and max values
• standard plot shows absolute limits for obtaining accurate results

Question 11

Planning ahead

Answer 11

• always think in advance about what kind of results are expected before running the test assay

Question 12

what to do with negative results?

Answer 12

• negative results gives you an indication to develop a new approach; why is it negative?
• try at least 3 times and see if continuously negative