Chromatography Terminology

The following lists the meanings and units of all symbols (unless dimensionless):

<<Common Terminology>>

A: Absorbance (Equations 3.1, 3.2); also referred to as area

CAN: Acetonitrile

B (%B): Strong solvent in a binary mobile phase (% v/v)

C8, C18: Bond length of alkyl-bonded phases (octaalkyl or octadecyl)

CD: Cyclodextrin

CV: Coefficient of variation (usually expressed as %); Equation 15.3

dC: Column inner diameter (cm)

dP: Particle diameter (μm)

DAD: Diode array detector

EC: Electrochemical (detector)

F: Flow rate (ml/min)

FL: Fluorescence (detector)

GS: Gradient slope parameter (Equation 8.2a); k* = 20/GS

h: Peak height

HP: Hewlett-Peckard

HPLC: High Performance Liquid Chromatography

ID: Inner diameter, dC

IEC: Ion-exchange chromatography IPC: Ion-pair chromatography

k: Retention factor (Equation 2.4)

k*: Effective or average value of k in gradient elution (Equation 8.1)

ka, kZ: k values of the first peak (a) and last peak (z) in the chromatogram

L: Column length (cm)

LC-MS: Liquid chromatography-mass spectrometry

M: Molecular weight

MC: Methylene chloride

MeOH: Methanol

MS: Mass spectrometry

MTBE: Methyl-t-butyl ether

N: Number of column plates (Equation 2.82.8b)

N: Noise (Equation 3.3, Figure 3.3)

NARP: Non-aqueous reversed-phase HPLC

NPC: Normal-phase chromatography

P: Column pressure drop (usually expressed in psi) (Equation 2.9)

pKa: Acidity constant of acid or proton-donating base

PAH: Polycyclic aromatic hydrocarbon hydrocarbon)

RS: Resolution (Equation 2.1)

RI: Refractive Index

RPC: Reversed-Phase Chromatography S: Signal; Equation 3.3; Figure 3.3; and parameters defined by Equation 6.1

tD: Delay or retention time (min, used in gradient elution); equal to VD/F

tG: Gradient time (min)

tR: Retention time (min) (Figure 2.2); equal to tO(1+k)

tRa,tRz: Retention times of the first peak (a) and the last peak (z) in the chromatogram, tR (min) (Figure 8.6a)

tO: Column dead time (min) (Equation 2.5)

t1,t2: Retention times of adjacent peaks 1 and 2 (min)

TEA: Triethylamine

TEA: Tetrahydrofuran

UV: Ultraviolet spectrum

VD: Delay or retention volume (mL); the volume between the gradient mixer and the column inlet (including the mixer volume)

Vm: Column dead volume (mL) (Equation 2.6); Vm: The volume of the mobile phase inside the column, excluding the solvent adhering to the stationary phase.

Vmax: Maximum sample volume (mL) (Equation 13.1)

Va: Sample volume (mL)

w: Weight (mg); also the peak width at half-peak height (min)

wmax: Maximum injection volume without overloading the column (mg) (Equation 2.17)

wS: Saturation capacity of the column (mg) (Equation 13.4)

W: Peak width at the bottom (min) (Figure 2.2)

Wth: Contribution of large injection volume to peak width at the bottom (min) (Equation 13.2)

WO: Peak width at the bottom (min) of small injection volume

W1/2: Peak width at half-peak height (min) (Figure 1.1)

a: Separation factor, equal to k2/k1, where k2 and k1 are the k values of adjacent peaks 2 and 1, respectively.

△tR: tRz - tR (min)

△%B: Change in %B during gradient elution

ε: Molar absorption coefficient

εo: Normal phase HPLC Strength of solvent or solvent mixture

η: Viscosity (CP)

<<Uncommon symbol>>

C: Concentration at peak maxima (mol/L)

CO: Concentration of solute in injected sample (mol/L)

GI: Chemical ionization (MS)

DGA: N,N-dimethyl-1-naphthamide; (also dimethylaniline)

EI: Electron ionization (MS)

ELS: Evaporative light scattering

EtOAc: Ethyl acetate

FAB: Fast atomic bombardment (MS)

FD: Field desorption (MS)

h: Folded plate height, equal to H/dP (Equation 2.11)

HB: Hydroxybenzoic acid (Figures 7.8, 7.17 and 7.19)

HFBA: Hyptafluorobutyric acid IPA: Isopropanol

kW: k-value with water as the mobile phase (Equation 6.1)

LCEC: Liquid Chromatography Electrochemical Detector

LD: Laser Desorption/Extraction (MS)

LSIMS: Liquid Secondary Ion Mass Spectrometry

MALDI: Matrix-Assisted Laser Desorption/Extraction Ionization

MP: Methylparaben

[P-]m: Concentration of ion-pairing reagent P- in the mobile phase (mmol/L)

PAD: Pulse Current Analyzer

PBP: Polar Bonded Phase

PD: Plasma Desorption/Extraction (MS) PP: Propylparaben

PTH: Hydantoin

R+, R-: Charged functional groups in anion- and cation-exchange columns, respectively (Equations 7.4 and 7.5 [e.g., -N(CH3)3+ and -SO3-])

RF: Response factor

TBA+: Tetrabutylammonium ion

tBME: See MTBE

TMS: Trimethylsilyl (also C1)

TNB: 1,3,5-Trinitrobenzene

TOF MS: Time-of-flight mass spectrometry

TSP: Thermal spray (MS)

u: Mobile phase velocity through the column (cm/s); equal to L/to

V: Peak width (mL)

Vc: Contribution of peak broadening within the column to V; also expressed as peak width at small sample volumes (mL) (Equation 2.16)

VR: Retention volume (mL) W: Peak width (min) (Equation 2.12)

Wc, WS: Contributions (min) of column, injector, continuous tube, and flow cell to W, respectively

Wlc, Wfc: (Equation 2.12)

X, X1: Solutes without characteristic structures (Figures 7.8, 7.17, and 7.19)

X2, X3

XB: Mole fraction of solvent B in the mobile phase

V: Reduced velocity, equal to udp/Dm (Equation 2.11)

б: Standard deviation of the Gaussian curve; equal to 1/4 of the peak bottom

ι: Detector response time constant (S)

φ: Volume fraction of solvent B in the mobile phase; equal to 0.01%B