HPLC & OTHER MISC. SEPARATION METHODS Flashcards
most versatile and widely used type of elution chromatography
High – Performance Liquid Chromatography (HPLC)
is a process in which dissolved gases are swept out of a solvent by bubbles of an inert, insoluble gas
Sparging
elution with a single solvent or solvent mixture of constant composition is termed an __
isocratic elution.
in HPLC is one in which the solvent composition remains constant.
isocratic elution
in HPLC is one in which the composition of the solvent is changed continuously or in a series of steps.
gradient elution
produce a pulse-free delivery whose flow rate is easily controlled
Screw – Driven Syringe type
used in almost all commercial instruments
Reciprocating Pump
-Used for mobile – phase conditioning
Scavenger Column
Removes particulates and other solvent impurities
Guard Column
Fractionation is based on molecular size
Powerful technique that is particularly applicable to high – molecular mass species
Size – Exclusion Chromatography
Used to separate analytes into their optical isomers using the chiral stationary phase
Chiral Chromatography
Such mirror images are called __ .
enantiomers.
is a chiral mobile-phase additive or a chiral stationary phase that preferentially complexes one of the enantiomers
chiral resolving agent
once called two-dimensional chromatography, although this term has now come to signify the coupling of two chromatographic techniques with different separation mechanisms.
Planar Chromatography
used in fractionation of sugar and amino acids
Paper Chromatography
sorbent of paper chromatography
Whatman paper
it is used for drug testing screening (semiquantitative screening test)
Thin – Layer Chromatography
Sample molecule are separated by electro – osmotic flow (EOF)
Capillary Electrophoresis
Is a hybrid of HPLC and capillary electrophoresis (CE) that offers some of the best features of the two methods.
Capillary Electrochromatography (CEC)
- A system of ensuring accuracy and precision in the laboratory by including quality control reagents in every series of measurement
Quality Control
It is the ability of an analytical method to measure the smallest concentration of the analyte of interest
Sensitivity
It is the ability of an analytical method to measure only the analyte of interest
Specificity
It is the nearness or closeness of the assayed value to the true or target value
Accuracy
The ability of an analytical method to give repeated results on the same sample that agree with one another
Precision or Reproducibility
The degree by which a method is easily repeated
Practicability
The ability of an analytical method to maintain accuracy and precision over an extended period of time during which equipment, reagents, and personnel may change
Reliability
True Positive
Is the ability of the test to detect the proportion of individuals with that disease who test positive with the test
Diagnostic Sensitivity
True Negative
Is the ability of the test to detect the proportion of individuals without the disease who test negatively for the disease.
Diagnostic Specificity
-It is present in all measurements
it is due to chance and can be both positive and negative
It is the basis for varying differences between repeated measurements.
Random Error
-Is an error that influences observations consistently in one direction(constant difference)
It is detected as either positive or negative bias
Often related to calibration problems, deterioration of reagents and control materials, unstable and inadequate reagent blanks, contaminated solutions, failing instrumentation and poorly written procedures.
Systematic Error
Refers to the difference between the target value and the assay value.
It is independent of sample concentration.
Constant Error
Results in greater deviation from the target value due to higher sample concentration.
Exists when the difference between the test method and the comparative method values are proportional to the analyte concentration
Proportional/ Slope/ Percent Error
The highest frequency of clerical errors occurs with the use of handwritten labels and request forms
Clerical Error
-It occurs when the date set can be accurately described by the SD and the mean.
Gaussian Curve (Bell – Shaped Curve)
-It calculates the difference between the QC results and the target means
Cumulative Sum Graph (CUSUM)
-It is used to compare results obtained on a high and low control serum from different laboratories.
Youden/ Twin Plot
Most widely used system in clinical laboratory.
Shewhart Levey – Jennings Chart
-Formed by control values that either increase of decrease for six consecutive days.
Main Cause: Deterioration of reagents
Trend
-It is formed by the control values that distribute themselves on one side or either side of the mean for six consecutive days.
Shift in the reference range is due to transient instrument differences.
Main Cause: Improper Calibration of Instruments
Shift
These are control values that are far from the main set of values’
They are highly deviating values
Caused by random or systematic errors
Outliers
