Getting Started in HPLC

Section 0. The Language of HPLC: I

A

B

C

D

E

F

G

H

I

J

K

L

M

N

O

P

Q

R

S

T

U

V

W

X

Y

Z

   
INJECTOR: the 6-port sample valve used to introduce a precise volume of sample into the LC system. Also called an INJECTION VALVE.


Standard 6-port injector


   
INLET CHECK VALVE: the check valve on an LC pump that allows mobile phase to flow from the reservoir to the pump, but not in the reverse direction. See CHECK VALVE.


Cross-sectional diagram of a "generic" single-piston HPLC pump.


   
INLET FILTERS: 10-micron frits attached to the inlet lines to the pump that filter the mobile phase entering the pump and help anchor the inlet line in the reservoir . Also called SINKERS. See RESERVOIR.


 
IN-LINE FILTER: a frit (usually 0.5 or 2 micron porosity) held in a container ("frit-holder") and connected between the sample injector and LC (analytical) column.


   
INJECTION SOLVENT: the solvent that the sample is dissolved in before it is injected into the LC system.


 
INJECTION VALVE: see INJECTOR.


 
INTAKE STROKE: movement of the piston of a pump so as to draw mobile phase into the pump cylinder from the reservoir.


   
INTEGRATOR: a module that measures the area of bands in an LC (or CC) chromatogram. Integrators may also record the chromatogram, measure retention times, and perform simple calculations.


 
INTERFERENCE: an unwanted peak that overlaps one of the desired peaks in a chromatogram. Interferences reduce the reliability of the results.


 
INTERNAL STANDARD: a compound added to calibrators and samples in order to improve precision.


 
INTERNAL STANDARD METHOD: a calibration procedure that involves addition of a compound (the "internal standard") to each sample and calibrator to be run in a given LC analysis procedure.


 
ION EXCHANGE CHROMATOGRAPHY: an HPLC method, different from reversed-phase chromatography. This method uses water solutions as the mobile phase and separates ions, acids and bases.


 
ION PAIR CHROMATOGRAPHY: an HPLC method, different from reversed- phase chromatography. It uses similar columns and mobile phases, but is especially suited for separations of acids and bases.


 
ION PAIR REAGENT: a compound that is added to the mobile phase to carry out ion pair chromatography.


 
ISOCRATIC: refers to an HPLC separation where the mobile phase composition stays the same during the run (the usual way LC is carried out). Isocratic separations are the opposite of gradient elution. Isocratic means "equal-strength" in Greek, meaning that mobile phase strength stays constant during the run. See also GRADIENT ELUTION.


 
   
 

 


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Last revised: April 02, 2001.