Intro Flashcards
What do Analytical Scientists use?
Different methods.
Different instruments.
Where does the choice of methods and instruments depend?
On analyte’s nature.
What questions do analytical scientists try to answer?
- What have I got?
- How much of it do I have?
- But…How confident are you?
What does the question ‘What have I got’ talk about?
Tests and processes quality.
What does the question ‘How much of it do I have’ talk about?
Substance, concentrations quantity: Forensic.
Was the substance the cure or the cause of patient’s illness?: Biomedical.
What does the question ‘But…How confident are you?’ talk about?
Powerful, correct quality assurance and statistical analysis.
Repeat analysis for incorrect results.
Represent truly the final result.
What problems might occur during an experiment?
Poor sample. Contamination. Wrong technique. Preplanned falsification. Poor calculation. Incorrect units.
How can the sample be poor?
When it is:
Wrong.
Not representative of the whole.
Small, not enough divided.
When can the sample be contaminated?
If it is not:
Stored and used correctly.
Identifiable.
Labelled correctly for particular analysis.
How can the wrong technique be prevented in an analysis?
By recording properly sample and results.
How can poor calculations of maths be prevented in an analysis?
By doing them:
Properly.
Powerfully.
Understanding every step.
How can incorrect units present in an analytical experiment?
By incorrect calculations.
Errors.
What can an arithmetical error cause to someone?
Jail.
How can someone be guilty because of an arithmetical error?
Wrong multiplication.
Large/small figure.
Not same to true value.
What must we be in terms of calculations in analysis?
Extremely careful in the whole process and data analysis of numbers.
On what do analytical results depend?
Representative sample. Sample honesty/integrity. Analysis method accurate and precise. Analyse right sample. Analyse right person/place.
What does GIGO mean?
Garbage In Garbage Out.
What must the sample be?
Site representative.
For what is the sampler responsible?
Representativeness of sample.
What might happen in an experimental and analytical process?
Experiment in lab –> given to analyst for analysis.
What happens when the sample is liquid?
The liquid is the whole sample representative.
What happens when the sample is a powder?
Take a small part of the sample –> mix up –> coning and quartering process –> take sample.
What must be taken in a method of experimental process?
Accuracy.
Precision.
Whose responsibility are the results taken from the experimental method?
The analysts.
What is the method?
The whole procedure.
What does the method include?
Sample selection. Sample preparation. Weighing. Dissolving. Purification = unwanted material removed. Analysis. Results.
What does the sample integrity involve?
Correct sample.
Correct patient details.
Nothing has changed.
Which 3 factors ensure that the sample is correct?
- Traceability.
- Good record keeping.
- Secure/safe storage.
How can we make sure it is the correct sample?
Keep sample chain. Labelling correctly. Secure storage. Cleanliness. Avoid contamination = false effects
What can cause degradation of samples?
Light. Heat. Oxidation. Contamination. Container loss. Bacterial action. Physical contact. Material loss. Solubility changes.
How can light and heat cause degradation of samples?
By releasing energy.
Leading to different reactions.
How can solubility changes cause sample degradation?
Uncontrolled temperature.
Too much heat –> precipitation.
What can be done to prevent sample degradation?
Store in dark, cool place.
Use suitable containers-specifically designed.
Acidify solutions.
Let little air space in container.
Why should acidify solutions to prevent sample degradation?
Metals react with water and air and they react.
Keep pH controlled.
What else is needed in forensic analysis?
Signature of sample keeping.
Logbook of recorded samples.
Logbook of accessibility of sample.
What does the Quality Assurance programme require?
Use of known chemicals from known batches.
Recorded analytical specifications.
Shelf life.
Use by date.
Why a Quality Assurance programme should be followed?
To identify wrong situations/chemicals used.
Minimise contamination.
What is exactly a Quality Assurance?
A system.
What does the Quality Assurance system state?
What will be done. Analysis type. What checks, controls will be carried out. Reagents. Chemicals. Records will show what has been done. What expected.
Which is an organisation that will approve quality systems?
ISO9000.
What is an accreditation scheme for l laboratories?
UKAS (UK Accreditation Service).
NAMAS (National Accreditation of Measurement and Sampling).
What is only accredited?
Only some standard procedures.
What will any organisation have?
Its own QA system.
Why should any organisation have its own QA system?
For analysis conditions.
Where do own adaptive techniques depend in the lab?
On lab actions.
How are records characterised?
Important.
What is required for applications?
Properly noted laboratory notebooks.
Results’ proof.
Evidence.
Not destroyed things.
What must be noted in a laboratory notebook?
How things were done.
Written process.
What will be checked with the help of a noted laboratory notebook?
Calculations.
Right/wrong things.
What is necessary to be written in a lab notebook?
Much detail.
Where does the lab notebook belong?
To the company we work for.
Not to us.
Why are records important?
To explain what occurred.
On what we can not rely?
Our memory.
What can not be characterised as a result?
A measurement.
What do measurements show?
Data.
Concentration range.
What happens to the data and concentration range?
The are analytically processed.
Give results.
What be a rubbish and not accurate graph of data?
A non informative. Non labelled axis. Errors uncommented. No units on axis. Wrong units on axis. Meaningless conclusion. Graph uncommented.
What can be a proper graph of data?
Labelled axis.
Units.
Good structure.
Arrive at a result.
What should measurements include?
Units.
What should results be?
Calculated.
What do calculations need?
Validating.
What should be done with errors?
Estimation.
What should be done on the result?
Comment.
What can lead to wrong answer that need to be checked?
Uncertainties.
What do the results need to be?
Confident.
