Getting Started in HPLC

Section 0. The Language of HPLC: N

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

   
NANOGRAM (ng): a unit of mass, equal to one billionth of a gram. See Section 4B for relation to other units of mass.


 
NANOMETER (nm): a unit of length used to measure the wavelength of light used in a photometric detector. See WAVELENGTH.


 
NOISE: in HPLC this usually refers to an irregular baseline that is hard to measure; all baselines become "noisy" if the attenuation of the detector is decreased enough. The two chromatograms shown below differ only in the amount of baseline noise

 
   
NONLINEAR: an LC method is said to be NONLINEAR when plots of peak-size vs sample concentration are not straight lines. See LINEAR.


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


   
NONPOLAR: compounds, solvents or bonded phases that dissolve readily in solvents such as hexane or prefer such solvents in place of water; nonpolar substances do not dissolve in water. Nonpolar substances are often referred to as HYDROPHOBIC.


 
NORMAL-PHASE LC: a less-common form of HPLC. Non-water-containing mobile phases are used with special column packings that have a hydrophilic surface layer.


 
   
 

 


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Last revised: April 02, 2001.