ASTM E682-92(2019)

Standard Practice for Liquid Chromatography Terms and Relationships

ABSTRACT
This practice deals with the terms, parameters, symbols, units, and relationships used in liquid column chromatography. Most of the terms covered herein should also apply to other kinds of liquid chromatography, notably planar chromatography such as paper or thin-layer chromatography. These terms include the names of techniques, apparatuses and reagents, the parameters and symbols used for chromatogram data readout, and the retention parameters, symbols and units.
SCOPE
1.1 This practice deals primarily with the terms and relationships used in liquid column chromatography. However, most of the terms should also apply to other kinds of liquid chromatography, notably planar chromatography such as paper or thin-layer chromatography.  
Note 1: Although electrophoresis can also be considered a liquid chromatographic technique, it and its associated terms have not been included in this practice.  
1.2 Since most of the basic terms and definitions also apply to gas chromatography, this practice uses, whenever possible, symbols identical to Practice E355.  
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 31-Aug-2019
• ICS: 01.040.71 - Chemical technology (Vocabularies)
• ICS: 71.040.50 - Physicochemical methods of analysis
• Technical Committee: E13 - Molecular Spectroscopy and Separation Science
• Drafting Committee: E13.19 - Separation Science

Relations

• Replaces: ASTM E682-92(2011) - Standard Practice for Liquid Chromatography Terms and Relationships
• Effective Date: 01-Sep-2019
• Refers: ASTM D3016-97(2018) - Standard Practice for Use of Liquid Exclusion Chromatography Terms and Relationships
• Effective Date: 01-Nov-2018
• Refers: ASTM E1151-93(2011) - Standard Practice for Ion Chromatography Terms and Relationships
• Effective Date: 01-Nov-2011
• Refers: ASTM E355-96(2007) - Standard Practice for Gas Chromatography Terms and Relationships
• Effective Date: 01-Mar-2007
• Refers: ASTM E1151-93(2006) - Standard Practice for Ion Chromatography Terms and Relationships
• Effective Date: 01-Sep-2006
• Refers: ASTM D3016-97(2010) - Standard Practice for Use of Liquid Exclusion Chromatography Terms and Relationships
• Effective Date: 10-Mar-2003
• Refers: ASTM D3016-97(2003) - Standard Practice for Use of Liquid Exclusion Chromatography Terms and Relationships
• Effective Date: 10-Mar-2003
• Refers: ASTM E355-96 - Standard Practice for Gas Chromatography Terms and Relationships
• Effective Date: 01-Jan-2001
• Refers: ASTM E355-96(2001) - Standard Practice for Gas Chromatography Terms and Relationships
• Effective Date: 01-Jan-2001
• Refers: ASTM D3016-97 - Standard Practice for Use of Liquid Exclusion Chromatography Terms and Relationships
• Effective Date: 10-Apr-1997
• Refers: ASTM E1151-93(2000) - Standard Practice for Ion Chromatography Terms and Relationships
• Effective Date: 15-Jul-1993
• Referred By: ASTM E3297-21 - Standard Test Method for Lipid Quantitation in Liposomal Formulations Using High Performance Liquid Chromatography (HPLC) with a Charged Aerosol Detector (CAD)
• Effective Date: 01-Sep-2019
• Referred By: ASTM E3324-22 - Standard Test Method for Lipid Quantitation in Liposomal Formulations Using Ultra-High-Performance Liquid Chromatography (UHPLC) with Triple Quadrupole Mass Spectrometry (TQMS)
• Effective Date: 01-Sep-2019
• Referred By: ASTM F1500-98(2019) - Standard Test Method for Quantitating Non-UV-Absorbing Nonvolatile Extractables from Microwave Susceptors Utilizing Solvents as Food Simulants (Withdrawn 2024)
• Effective Date: 01-Sep-2019
• Referred By: ASTM D5910-05(2019) - Standard Test Method for Determination of Free Formaldehyde in Emulsion Polymers by Liquid Chromatography
• Effective Date: 01-Sep-2019

Overview

ASTM E682-92(2019) – Standard Practice for Liquid Chromatography Terms and Relationships is an international standard developed by ASTM International. The standard defines the essential terminology, parameters, symbols, and relationships used in liquid column chromatography, with extended relevance to other forms of liquid chromatography such as planar chromatography (e.g., paper and thin-layer chromatography). It provides a common language for users, researchers, and manufacturers in the field of liquid chromatography, promoting clarity, consistency, and the harmonization of terminology in scientific communication and instrumentation documentation.

Key Topics

• Terminology: Definitions of key terms associated with liquid chromatography, including apparatus, techniques, reagents, chromatogram readouts, and parameters such as retention time and peak width.
• Parameters, Symbols, and Units: Standardized symbols and SI units for variables commonly encountered in chromatographic analysis-such as flow rate, retention volume, capacity ratio, number of theoretical plates, and peak resolution.
• Chromatographic Techniques and Modes: Guidance on standardizing names for various chromatography types-such as liquid-liquid chromatography (LLC), liquid-solid chromatography (LSC), ion-exchange chromatography, affinity chromatography, and the distinctions between normal phase and reversed-phase separations.
• Apparatus and System Components: Clarification of the nomenclature for different system parts, including pumps, sample inlet systems, columns, detectors, and fraction collectors.
• Readout and Data Interpretation: Standard definitions for chromatogram features (e.g., baseline, peaks, peak width, resolution), which facilitate consistent data analysis and reporting.
• Preferred Terminology: Recommendations for nomenclature, discouraging the use of ambiguous or outdated terms to avoid confusion within the chromatography community.

Applications

ASTM E682-92(2019) is practically valuable for:

• Method Development and Validation: Ensures uniformity in defining and reporting chromatographic parameters across different laboratories and industries.
• Instrumentation Documentation: Manufacturers of chromatographic equipment and software reference these terms and symbols to ensure clear, consistent user manuals and data outputs.
• Regulatory Compliance: Adoption of standardized terminology facilitates communication with regulatory agencies and aligns with the international principles established by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
• Training and Education: Academic and industrial training programs use these definitions to instruct laboratory personnel in best practices for liquid chromatography.
• Quality Assurance and Audits: Harmonized language supports effective quality control and ensures reproducibility in chromatographic analyses, aiding internal and external audits.

Related Standards

For comprehensive application and deeper understanding, the following related ASTM standards are recommended:

• ASTM D3016 – Practice for Use of Liquid Exclusion Chromatography Terms and Relationships: Focuses on nomenclature specific to liquid exclusion chromatography.
• ASTM E355 – Practice for Gas Chromatography Terms and Relationships: Provides analogous standardized terminology for gas chromatography, with symbols harmonized with E682 when possible.
• ASTM E1151 – Practice for Ion Chromatography Terms and Relationships: Addresses terminology for ion chromatography, a special application within liquid-solid chromatography.
• USP Chromatography Chapters: For application in pharmaceutical analysis, coordination with United States Pharmacopeia (USP) chromatographic system suitability guidelines may be required.

By adhering to ASTM E682-92(2019), organizations ensure consistency, accuracy, and international alignment in the practice, documentation, and interpretation of liquid chromatography, supporting reliable scientific and industrial outcomes.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: E682 − 92 (Reapproved 2019)
Standard Practice for
Liquid Chromatography Terms and Relationships
This standard is issued under the fixed designation E682; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope 3. Names of Techniques
NOTE 2—In the chromatographic literature one may often find the term
1.1 This practice deals primarily with the terms and rela-
high-performance (or high-pressure) liquid chromatography, abbreviated
tionships used in liquid column chromatography. However,
as HPLC.This term was introduced to distinguish the present-day column
most of the terms should also apply to other kinds of liquid
chromatographic techniques employing high inlet pressures and columns
chromatography, notably planar chromatography such as paper containing small diameter packing from the classical methods. The
utilization of this term or any derivative term (for example, HPLSC for
or thin-layer chromatography.
high-performance liquid-solid chromatography) is not recommended.
NOTE 1—Although electrophoresis can also be considered a liquid
Similarly, the use of the term high-performance thin-layer
chromatographic technique, it and its associated terms have not been
chromatography, abbreviated as HPTLC, describing newer variations of
included in this practice.
thin-layer chromatography, is also not recommended.
1.2 Since most of the basic terms and definitions also apply
3.1 Liquid Chromatography, abbreviated as LC, comprises
to gas chromatography, this practice uses, whenever possible,
all chromatographic methods in which the mobile phase is
symbols identical to Practice E355.
liquid under the conditions of analysis. The stationary phase
may be a solid or a liquid supported by or chemically bonded
1.3 The values stated in SI units are to be regarded as
to a solid.
standard. No other units of measurement are included in this
standard.
3.2 The stationary phase may be present on or as a plane
1.4 This international standard was developed in accor- (Planar Chromatography), or contained in a cylindrical tube
dance with internationally recognized principles on standard-
(Column Chromatography).
ization established in the Decision on Principles for the
3.3 Separation is achieved by differences in the distribution
Development of International Standards, Guides and Recom-
of the components of a sample between the mobile and
mendations issued by the World Trade Organization Technical
stationary phases, causing them to move along the plane
Barriers to Trade (TBT) Committee.
surface or through the column at different rates (differential
migration).
2. Referenced Documents
3.3.1 In Planar Chromatography, the differential migration
2.1 ASTM Standards:
process will cause the sample components to separate as a
D3016 Practice for Use of Liquid Exclusion Chromatogra-
series of spots behind the mobile phase front.
phy Terms and Relationships
3.3.2 InColumnChromatography,thedifferentialmigration
E355 Practice for Gas Chromatography Terms and Relation-
process will cause the sample components to elute from the
ships
column at different times.
E1151 Practice for Ion Chromatography Terms and Rela-
3.3.3 InDry-ColumnChromatography,mobilephaseflowis
tionships
stopped as soon as the mobile phase has reached the end of the
column of dry medium. This column can be glass or a rigid or
flexible solvent compatible plastic. Solute visualization and
This practice is under the jurisdiction of ASTM Committee E13 on Molecular
Spectroscopy and Separation Science and is the direct responsibility of Subcom- recovery are from the extruded or sliced column packing.
mittee E13.19 on Separation Science.
3.3.4 In Flash Chromatography, mobile phase flow is con-
Current edition approved Sept. 1, 2019. Published September 2019. Originally
tinuedafterthemobilephasehasreachedtheendofthecolumn
approved in 1979. Last previous edition approved in 2011 as E682–92 (2011). DOI:
10.1520/E0682–92R19.
of dry medium until elution of the desired components is
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
achieved. Often low pressures, compatible with the materials
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
of construction of the column, are applied to the top of the
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. column to speed up the elution.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E682 − 92 (2019)
3.4 The basic process of selective distribution during the smaller molecules. See Practice D3016 for further details of
chromatographic process can vary depending on the type of nomenclature for this technique.
stationary phase and the nature of the mobile phase.
3.5 Inliquidchromatography,thecompositionofthemobile
3.4.1 In Liquid-Liquid Chromatography, abbreviated LLC,
phase may be constant or changing during a chromatographic
the stationary phase is a liquid and the separation is based on
separation.
selective partitioning between the mobile and stationary liquid
3.5.1 The termIsocratic may be used when the composition
phases.
of the mobile phase at the column inlet is kept constant during
3.4.2 InLiquid-SolidChromatography, abbreviated as LSC,
a chromatographic separation.
the stationary phase is an interactive solid. Depending on the
3.5.2 The term Gradient is used to specify the technique
type of the solid, separation may be based on selective
when a deliberate change in the mobile phase operating
adsorption on an inorganic substrate such as silica gel, or an
condition is made during the chromatographic procedure. The
organic gel. In this definition, Ion-Exchange Chromatography
change is usually in mobile phase composition, flow rate, pH,
is considered to be a special case of LSC in which the
or temperature. The first-named change is called Gradient
interactive solid has ionic sites and separation is due to ionic
Elution. Flow Programming is a technique where the mobile
interaction.
phase linear velocity is changed during the chromatographic
3.4.2.1 In this definition, Ion Exchange Chromatography is
procedure. The changes are made to enhance separation or to
considered to be a special case of LSC in which the interactive
speed elution of sample components, or both. Such changes in
solid has permanently bonded ionic sites and separation is due
operating conditions may be continuous or step-wise.
to electrostatic interaction.
3.6 In the standard modes of liquid chromatography, the
3.4.2.2 In this definition, Ion Pair Chromatography is con-
stationary phase is more polar than the mobile phase. This is
sidered to be a special case of LSC in which ionic counterions
referred to as Normal Phase Chromatography. The opposite
are added to the mobile phase to effect the separation of ionic
case is also possible, in which the mobile phase is more polar
solutes. In this technique both electrostatic and adsorptive
than the stationary phase. This version of the technique is
forces are involved in the separation.
called Reversed-Phase Chromatography.
NOTE 3—Other terminology for this technique include, but are not
3.7 Planar Chromatography comprises two versions: paper
limited to, extraction chromatography, paired ion chromatography, soap
chromatography, ion pair extraction chromatography, ion pair partition chromatography and thin-layer chromatography.
chromatography, and ion interaction chromatography, but utilization of
3.7.1 In Paper Chromatography, the process is carried out
these terms is not recommended.
on a sheet or strip of paper. Separation is usually based on LLC
3.4.2.3 In this definition, Affınity Chromatography is con- inwhichwaterheldonthecellulosefibersactsasthestationary
sidered to be a special case of LSC in which special ligands are phase. Separation based on LSC may also be utilized when the
bonded to a stationary phase so that bio-specific interactions paper is impregnated or loaded with an interactive solid.
(for example, antibody/antigen, enzyme/substrate) may be
3.7.2 In Thin-Layer Chromatography, the solid stationary
invoked to effect the separation.
phase is utilized in the form of a relatively thin layer on an
3.4.2.4 In this definition,IonChromatography is considered inactive plate or sheet.
to be a special application of LSC in which the ion exchange
3.7.3 In any version of planar chromatography, the mobile
mechanism is still effecting the separation. Special columns or
phase may be applied in a number of ways. In normal usage,
devices, after the separating column, may be needed to remove
Ascending, Descending, and Horizontal Development, the
higher concentrations of inorganic ions which might otherwise
mobile phase movement depends upon capillary action. In
interfere with the detectability using conductivity. See Practice
Horizontal Development, the mobile phase may move pre-
E1151 for further details of nomenclature for this technique.
dominantly linearly or radially. In Radial Development, the
3.4.2.5 In this definition, Hydrophobic Interaction mobile phase is applied as a point source. Devices have been
Chromatography, is considered to be a special application of employed which accelerate the mobile phase movement on
LSC in which the separation is based upon interaction of the planar layers by pressure or centrifugal force.
hydrophobic moieties of the solutes and the hydrophobic
3.7.4 The Mobile Phase Front is the leading edge of mobile
moieties of the sites on a reversed phase packing. High to low
phase as it traverses the planar media. In all forms of
salt gradients are used to effect this type of separation.
development, including radial, the local tangent to the Mobile
3.4.3 In some cases, such as with bonded stationary phases, Phase Front is everywhere normal to the local direction of
the exact nature of the separation process is not fully estab- development.
lished and it may be based on a combination of liquid-liquid
3.7.5 Consecutive Developments of planar media may be
and liquid-solid interactions.
carried out after removal of the mobile phase from a previous
3.4.4 In Steric Exclusion Chromatography, the stationary development. If the consecutive development is accomplished
phase is a noninteractive porous solid, usually silica or an in the same direction as previously, this is Multiple Develop-
organicgel.Inthiscase,separationisaffectedbythesizeofthe ment. If a second development is accomplished at a right angle
sample molecules, where those which are small enough pen- to the first development, this is Two-Dimensional Develop-
etrate the porous matrix to varying extents and degrees while ment. Continuous development of planar media is possible by
those that are largest are confined to the interstitial region of allowing evaporation of the mobile phase near the Mobile
the particles. Thus, the larger molecules elute before the Phase Front.
E682 − 92 (2019)
3.7.6 Impregnation is the technique of applying a reagent to 4.3.3 Guard Column is a protector column placed between
the planar media to effect an enhanced separation or detection. the injector and the separating column. The purpose of this
This impregnation is accomplished by dipping or spraying a column is to be the final filter for the sample, adsorbing
reagent solution after the preparation of the medium, or by unwanted sample components that otherwise might bind irre-
incorporating during the manufacturing process. versibly to the separating column. It has a volume of no more
than ⁄20 the volume of the separating column. It may be filled
with any material which will effectively remove the unwanted
4. Apparatus
components without interfering with subsequent chromato-
4.1 Pumps—The function of the pumps is to deliver the
graphic processes.
mobile phase at a controlled flow rate to the chromatographic
4.3.4 ConcentratorColumn is a small column placed in-line
column.
at the loop injector for introducing a dilute sample which is
4.1.1 Syringe Pumps have a piston that advances at a
collected into it before elution onto the separating column.
controlled rate within a smooth cylinder to displace the mobile
NOTE 4—Other terminology for this technique include, but are not
phase.
limited to, trace enrichment column, collector column, and sample
4.1.2 Reciprocating Pumps have a single or dual chamber
concentration column, but utilization of these terms is not recommended.
from which mobile phase is displaced by reciprocating pis-
4.3.5 Column sizes with various internal diameters (ID) and
ton(s)ordiaphragm(s).Thechambervolumeisrelativelysmall
lengths can be made. Larger columns present no problems
compared to the volume of the column.
concerning nomenclature, but columns with small internal
4.1.3 PneumaticPumps employ a gas to displace the mobile
diameters are now being used. As pointed out by Basey and
phase either directly or through a piston or collapsible con-
Oliver as many as nine terms (capillary, microcapillary,
tainer. The volume within these pumps may be large or small
narrow bore capillary, micro, microbore, ultramicro, narrow
as compared to the volume of the column.
bore, small bore, and small diameter) have been seen in the
4.2 Sample Inlet Systems represent the means for introduc-
literature and with no clear distinction between them when the
ing samples into the column.
actual column ID is examined. It is recommended that all
4.2.1 Septum Injectors—Sample contained in a syringe is
descriptive terms regarding column ID be discontinued, that is,
introduced directly into the pressurized flowing mobile phase
packed column, 1000 µm ID×100 mm or open column,
by piercing an elastomeric barrier. The syringe is exposed to
250µm ID×1 m.
pressure and defines the sample volume.
4.3.6 Column Inlet is the end of a column where the mobile
4.2.2 Septumless Injectors—Sample contained in a syringe
phase is introduced.
is introduced into an ambient-pressure chamber, and the
4.3.7 Column Outlet is the end of a column where the
chamber is subsequently mechanically displaced into the
mobile phase exits.
pressurized flowing mobile phase. The syringe is not exposed
4.3.8 Frit is the porous element placed at the ends of a
to pressure and defines the sample volume.
chromatography column, or in a special device for in-line
4.2.3 Valve Injectors—Sample contained in a syringe (or
filtration to effect the removal of particulate material in the
contained in a sample vial) is injected into (or drawn into) an mobile phase or the sample solution.
ambient-pressure chamber which is subsequently displaced
4.4 Detectors are devices that respond to the presence of
into the pressurized flowing mobile phase. The displacement is
eluted solutes in the mobile phase emerging from the column.
by means of rotary or sliding motion. The chamber is a section
Ideally, the response should be proportional to the mass or
(loop) of tubing or an internal chamber. The chamber can be
concentration of solute in the mobile phase. Detectors may be
completely filled, in which case the chamber volume defines
divided either according to the type of measurement or the
the sample volume, or it can be partially filled, in which case
principle of detection.
the syringe calibration marks define the sample volume.
4.4.1 Bulk Property Detectors measure the change in a
4.3 Columns consist of tubes that contain the stationary physical property of the mobile phase passing from the
phase and through which the mobile phase flows. column. Thus a change in the refractive index, conductivity, or
dielectric constant of a mobile phase can indicate the presence
4.3.1 Separating Column is the column on which the
of eluting components.
separation of the solutes is accomplished.
4.4.2 Solute Property Detectors measure the physical or
4.3.2 Pre-column is a column that has been used classically
chemical characteristics of the component eluting from the
to precondition the mobile phase, placed between the pump
column. Thus, light absorption (ultraviolet, visible, infrared),
and the injector. In the instance of its use with liquid-liquid
fluorescence, and polarography are examples of detectors
separations involving coated stationary phases, such a column
capable of responding in such a manner.
contained an excess of the coating phase to presaturate the
4.4.3 Differential Detectors measure the instantaneous pro-
mobile phase so it would not strip the same phase from the
portion of eluted sample components in the mobile phase
coated stationary phase during the separation. Its predominate
passing through the detector or their instantaneous rate of
use today is as a protector column for silica based column
arrival at the detector.
packing materials. It is filled with large particle silica which is
slowly dissolved by polar, ionic mobile phases. By so doing,
the silicate saturated mobile phase cannot dissolve the silica
backbone of the analytical or preparative column. Basey, and Oliver, Journal of Chromatography, No. 251, 1982, p. 265.
E682 − 92 (2019)
4.4.4 Integral Detectors measure the accumulated quantity 5.1 The Mobile Phase is the liquid used to sweep or elute
of sample component(s) reaching the detector. the sample components along the planar surface or through the
4.4.5 The detectors used in liquid chromatography may also column. It may consist of a single component or a mixture of
bebasedonavarietyofotherphysicalorchemicalphenomena. components. The term eluent is often used for the preferred
Mobile Phase.
4.5 Fraction Collectors are devices for recovering time-
5.1.1 Degassing is the process of removing dissolved gases
separated fractional volumes of the column effluent. The
from the Mobile Phase before or during use. This can be
fraction collectors may be operated manually or automatically.
accomplished by sparging (with helium), sonicating, heating,
Automatic fraction collectors consist of a series of test tubes or
or applying a vacuum to the Mobile Phase.
flasks. Column effluent is carried to one of the vessels and after
5.2 TheStationaryPhase is the active immobile material on
a measured volume is collected or a set period of time has
the planar surface or within the column that retards the passage
passed, the system automatically places the next vessel into
of sample components by one of a number of processes or their
position to receive a corresponding aliquot.
combination. There are three types of stationary phase: Liquid
4.6 The Developing Chamber is a closed or open container,
Phases, Interactive Solids, and Bonded Phases. Inert materials
for either conventional or continuous development, respec-
that merely provide physical support for the stationary phase
tively. Customarily it is of relatively large internal volume,
are not part of the stationary phase.
used to enclose the media used in paper or thin-layer chroma-
5.2.1 TheLiquidPhase is a stationary phase which has been
tography and also the mobile phase. It may be lined with a
sorbed (but not covalently bonded) to a solid support, paper
porous paper (Saturated Development) or it may be unlined
sheet, or thin layer. Differences in the solubilities of the sample
(UnsaturatedDevelopment).Paperorplateequilibrationisalso
components in the liquid and mobile phase constitute the basis
possible by standing the paper or thin layer plate in the
for their separation. Examples of materials that can be used as
developing chamber containing the mobile phase for a given
liquid phases are β,β'-oxydipropionitrile, sil
...