Bio Analysis Flashcards
What is quantitative analysis
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Disease
• Dysregulation of the cell cycle is common during tumorigenesis (cancer display uncontrolled growth)
• Increased levels of CDK molecules and cyclins are sometimes found in human tumours, such breast cancer and brain tumours
• Inhibition of certain CDKs has been shown to inhibit tumour cell growth, induce apoptosis and cause tumour regressions in animal models
• CDKs are potential targets for new anticancer therapy
Analytical chemistry
a branch of chemistry that deals with the identification of compounds and mixtures (qualitative analysis) or the determination of the proportions of the constituents (quantitative analysis): techniques commonly used are titration, precipitation, spectroscopy, chromatography, etc. 1
Biochemical analysis:
characterisation of biological components within a sample using appropriate laboratory techniques
Qualitative Analysis
indicate whether a particular substance (analyte) is present above a threshold level
Marquis test
presence of alkaloids
Trinder spot test
presence of salicylates (aspirin)
hCG
human chorionic gonadotrophin
Quantitative Analysis:
determines the amount of a particular analyte present in the sample (e.g. the concentration of a drug in blood serum).
Accuracy
Closeness of a measured or derived data value to its true value
Precision
Closeness of values with repeated measurements
Sensitivity
• ability to detect small amounts of analyte in a sample
• OR the percentage of patients with the disease that will be correctly
identified as disease positive
Specificity:
• ability to detect only the analyte of interest in a sample
• OR the percentage of patients without the disease that receive a negative result
Why measure biological molecules?
Medicine:
• Blood hormone levels • Enzyme activity
• Drug levels
• Metabolites
• Clinical trials
Toxicology:
• Xenobiotics
• Drugs / metabolites
• Pharmacokinetics
• Anti-doping testing in sports
Forensics:
• Xenobiotics
• Drugs / metabolites
• Environmental toxins
• Other toxic compounds
Typical analytical scheme
Sample
Sub-sample
Extraction ; the test substance or remove the interfering substance before analysis can proceed
Separation; Separation procedures depend on physical or chemical characteristic of the compound
Detection
Result
Interpretation
Separation technique for polar molecules that are volatile,soluble,and absorbable
Gas-liquid chromatography Liquid-liquid chromatography
Liquid-gas chromatography
Separation technique for ionic molecules that are charged
Ion-exchange chromatography
Electrophoresis
Separating technique for molecules with a mass that have the physical property are diffusion and sedimentation
Gel filtration chromatography
Dialysis Ultracentrifugation
Separating technique for molecules with a shape that have the physical property of ligand binding
Affinity chromatography
Chromatography
-developed by a Russian botanist
-Technique that allows the resolution of a mixture of compounds as a consequence of the different rates at which they move through a stationary phase, under the influence of a mobile phase
Planar chromatography
The stationary phase is supported on a flat plate or in the fibres of a paper.
The mobile phase moves through the stationary phase by capillary action or by gravity.
• Paper chromatography
• Thin layer chromatography (TLC)
Column Chromatography:
The stationary phase is held in a tube through which the mobile phase is forced either by pressure or by gravity.
• Simple column chromatography
• High pressure liquid chromatography (HPLC) • Gas chromatography (GC)
Thin layer chromatography
-TLC plate (stationary phase): a sheet of glass, metal, or plastic coated with a thin layer of a solid adsorbent (usually silica or alumina)
-Samples are “spotted” at the base of the sheet and dried.
-Sheet is placed in the tank containing a shallow layer of solvent (mobile phase)
-Substances reacting to the stationary phase more strongly will have retarded migration.
Rf
distance travelled by substance /distance travelled by solvent
