Getting Started in HPLC

Section 0. The Language of HPLC: L

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

   
LINEAR: The LC method is said to be LINEAR when plots of peak-size versus sample concentration are straight lines. In practice, it is also desirable to have the plot pass through the origin.


The calibration plot is a graphical representation of the relationship between peak size and amount of analyte injected.


   
LINEARITY CHECK: The measurement of peak size in an LC assay for a series of samples of different concentration. The LC method is said to be LINEAR when plots of peak size versus sample concentration are straight lines and pass through the origin.


 
LIQUID CHROMATOGRAPH: the instrument or equipment used to perform an HPLC separation.


Agilent 1100 HPLC System


   
LIQUID CHROMATOGRAPHY (LC): a special kind of chromatography where separation takes place using a liquid or solvent that passes through a column. "LC" and "HPLC" are used interchangeably.


 
LIQUID-SOLID CHROMATOGRAPHY (LSC): another HPLC method, different from reversed-phase chromatography. It uses mobile phases that do not contain water. It is almost always classified as a type of NORMAL-PHASE CHROMATOGRAPHY. Also called ADSORPTION CHROMATOGRAPHY.


 
LITER (L): a unit of volume, equal to about a quart. See Section 4B for the relationship to other volume units.


 
LOOP: a piece of tubing in a sample injector that holds the sample to be injected and determines its volume.


Cross-sectional diagram of a generic injector.


   
LOT NUMBER: usually refers to columns prepared from the same batch of column packing, which therefore have the same separation properties and give the same retention times for bands in a given sample. Sometimes called BATCH NUMBER. Also refers to LC solvents bottled from the same manufacturing batch.


 
LOW-PRESSURE MIXING: a pumping procedure that mixes two or more solvents before the pump to form a mobile phase then delivers the mixture to the LC system. A single pump plus a controller are used, so such systems are often referred to as "one pump" systems. See also HIGH PRESSURE MIXING.


Thermo Separations Products one-pump gradient HPLC System


   
 

 


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Last revised: April 02, 2001.