Sample preparation and NPS Flashcards
What tests do not need to be extracted
immunoassay and direct injection techniques
what is sample extraction
removal of drug from a biological and dissolved in a solvent for mass spec
what is dilute and shoot and what do we use to test
liquid speciment + solvent + internal standard = liquid chromatography
What are cons with homogenization
heat labile analytes affected
contamination of specimens
what techniques involve homogenization
L/L extraction
solid phase extration
what is protein precipitation
separate protein solution to eliminate interferences
what chemical is used for protein precipitation
zinc sulfate, perchloric acid, ammmouniom sulfate and HCL and ORGANIC SOLVENTS
what is the purpose of internal standard for protein precipitation
account for drug recovery
what is liquid liquid extration
solutes transferring from aqueous to orgnic phase or vise versa
what does LLE rely on
parition coefficient bt orgnaic and aquieous phases
buffering / pH adjusted causes what for LLE
selectivity in the extration
what is the equation for partition coefficient and what does it mean
octanol/water
high# = lipophillic
low# = hydrophillic
what are amphoteric drusg
contains both acidic and basic fxnal groups
what does Solid phase extraction use
SPE uses a stationary phase where liquid flows inside of
how is separation done in SPE
physical and chemical properties of drug that bind due to electrostatic interations
what is the goal of SPE
high rention on the sorbent while low retention of interfering compounds
what is the process for SPE
- condition column = wet for uniform flow
- load sample
- wash - remove interference
- elute - removes interest analyte
what does solid phase microextration use
SPME uses solvent free sample prep and a coated fiber for volatile samples
which sorptive surface is larger, SPME or SPE
SPE
what samples can be ran for SPE and SPME
SPE - liquid
SPME - gas, liquid, semi solid
T/F SPME time of exposure is proportional to cencentration of analyte
T
What analysis is performed on SPME equilibrated samples
GC or LC (mass spec)
what is a problem with glucuronic acid and drugs
glucuronic acid is polar = make drugs more water soluble (renal excretion)
how does glucuronide affect liquid chromatography
highly polar = cannot be retained during separation = hinders quantitative ability
