Reagent Purity Labeling System and Interpretation Principles

Purity is an important indicator in reagent specifications used to characterize the target component, target element, active component, or specific quality attribute. In actual product labeling, purity does not always equal the mass percentage of a single compound. Its meaning may be jointly defined by the detection method, calculation basis, elemental basis, isomer composition, isotopic abundance, optical purity, and COA testing items.

Keywords: reagent purity; specification labeling; detection method; dry basis; metals basis; isotopic abundance; optical purity; COA

1 Basic Concepts of Purity

1.1 Definition of Purity

In reagent specifications, purity is usually used to indicate the required proportion of the target substance, target element, or target specification item. Common expressions include “≥98%,” “≥99%,” and “≥99.5%.”

Purity labeling should be interpreted according to the specific basis of expression, mainly including the following cases:

(1) Expressed by main component content

This is used for most organic small molecules, inorganic salts, standards, and general chemical reagents, indicating that the target main component meets the corresponding proportional requirement.

(2) Expressed by detection method

Examples include HPLC, GC, SDS-PAGE, and NMR, indicating that the purity is obtained under the specified detection method.

(3) Expressed by calculation basis

Examples include dry basis, anhydrous basis, and metals basis, indicating that the purity is calculated on a dry, anhydrous, or metal basis.

(4) Expressed by special quality attributes

Examples include atom%, ee, and sum of isomers, which involve special indicators such as isotopic abundance, optical purity, and total isomer content.

Therefore, purity is not a single number independent of detection conditions. It is a specification requirement achieved by the product under a specific quality control basis.

1.2 Common Forms of Purity Values

Purity fields commonly contain “≥,” “≤,” and range values. Different symbols correspond to different quality requirements.

(1) “≥”

This indicates that the target indicator is not lower than the labeled value. For example, “≥98%” means that the target component or target specification item reaches 98% or above.

(2) “≤”

This is often used to limit impurities, isomers, or non-target components. For example, “≤10% trans isomer” means that the trans isomer content is not higher than 10%.

(3) Range values

Examples such as “98.5%–101.5%” are commonly seen in pharmacopeial, standard, or titration-related products, indicating that the assay result should fall within the specified range.

The same value may have different meanings under different suffix conditions:

Labeling Form	Interpretation Focus
≥98%	The target component or target specification item is not lower than 98%
≥98% (HPLC)	Determined according to the HPLC detection basis
≥98% metals basis	Calculated on a metals basis
≥98% dry basis	Calculated on a dry basis
≥98 atom% D	Deuterium isotopic abundance is not lower than 98 atom%
≥98%, ≥99% ee	Both chemical purity and optical purity requirements are met

2 Main Types of Purity

2.1 Main Content-Type Purity

Main content-type purity is the most common form of purity expression and is usually expressed directly as a percentage.

(1) Common forms

Examples include “≥95%,” “≥98%,” “≥99%,” and “≥99.9%.”

(2) Main meaning

It indicates that the target main component or main specification item reaches the required proportion.

(3) Scope of application

It is commonly used for organic reagents, inorganic reagents, standards, and general chemicals.

(4) Interpretation points

When no detection method is labeled, it should not be assumed by default that HPLC, GC, or titration is necessarily used. The specific testing items should be based on the product COA or quality standard.

Table 1 Examples of Main Content-Type Purity

Expression	Meaning	Common Application Scenario
≥95%	Main component or specification item is not lower than 95%	General reagents and some raw materials
≥98%	Main component or specification item is not lower than 98%	Common organic/inorganic reagents
≥99%	Main component or specification item is not lower than 99%	High-purity reagents
≥99.9%	Main component or specification item is not lower than 99.9%	High-purity or special-purpose products
98.5%–101.5%	The assay result should fall within the specified range	Pharmacopeial, standard, or titration-related specifications

2.2 Detection Method-Defined Purity

Detection method-defined purity refers to purity expressions in which a detection method is indicated after the purity value.

(1) Common forms

Examples include “≥98% (HPLC),” “≥97% (GC),” “≥95% (SDS-PAGE),” and “≥98% (NMR).”

(2) Main meaning

This indicates that the purity result comes from a specified detection system and usually reflects the target component, main peak, main band, or related quantitative result within the detectable scope of that method.

(3) Interpretation points

Method purity is not necessarily equal to absolute mass fraction. For example, “≥98% (HPLC)” usually means that the target peak area or quantitative result meets the requirement under specified HPLC conditions. Whether moisture, inorganic salts, residual solvents, or non-responding impurities are included in the evaluation should be determined together with other testing items in the COA.

Table 2 Common Detection Method-Defined Purity

Abbreviation/Method	Chinese Meaning	Meaning in Purity Field
HPLC	High-performance liquid chromatography	Commonly used for purity determination of organic small molecules, peptides, nucleosides, natural products, etc.
GC	Gas chromatography	Commonly used for purity determination of volatile or semi-volatile organic compounds and solvent products
LC-MS	Liquid chromatography-mass spectrometry	Commonly used for target confirmation and related purity analysis
LC/MS-UV	Liquid chromatography-mass spectrometry/UV detection	Indicates a basis combining LC/MS and UV detection
LC/MS-ELSD	Liquid chromatography-mass spectrometry/evaporative light scattering detection	Suitable for analysis of some substances without obvious UV absorption
NMR	Nuclear magnetic resonance	Can be used for structural confirmation and purity assessment
qNMR	Quantitative nuclear magnetic resonance	Can be used for quantitative purity analysis
SDS-PAGE	Sodium dodecyl sulfate-polyacrylamide gel electrophoresis	Commonly used for purity evaluation of proteins, peptides, or enzymes
SEC-HPLC	Size exclusion high-performance liquid chromatography	Commonly used for analysis of proteins, peptides, polymers, monomers/aggregates
RP-HPLC	Reversed-phase high-performance liquid chromatography	Commonly used for peptides, protein fragments, and organic molecules
TLC	Thin-layer chromatography	Commonly used for rapid qualitative or semi-quantitative purity assessment
HPCE/CE	High-performance capillary electrophoresis/capillary electrophoresis	Commonly used for charged molecules, peptides, nucleic acids, or chiral components
PAGE	Polyacrylamide gel electrophoresis	Commonly used for purity assessment of protein or nucleic acid products
UV	Ultraviolet spectrophotometry	Commonly used for determination of products with UV absorption characteristics
enzymatic	Enzymatic method	Commonly used for enzyme substrates, sugars, coenzymes, or functional components
titration/T	Titration or titration-related assay	Commonly used for acid-base, redox, complexometric, or volumetric analysis products
AAS	Atomic absorption spectroscopy	Commonly used for metal element content determination
CHN	Carbon-hydrogen-nitrogen elemental analysis	Commonly used for confirmation of elemental composition or organic matter content
TGA	Thermogravimetric analysis	Commonly used for moisture, volatile matter, thermal stability, or inorganic residue-related determination

2.3 Calculation Basis-Type Purity

Calculation basis-type purity is purity expressed after conversion according to a specific basis and cannot be directly interpreted as the mass percentage of the sample as received.

(1) Common forms

These include dry basis, dry matter, anhydrous basis, metals basis, trace metals basis, REO, carbon basis, and active ingredients basis.

(2) Typical meanings

“≥99% (dry basis)” means that purity is not lower than 99% after calculation on a dry basis. “≥99.9% metals basis” means that the value is calculated on a metals basis. “≥99.9% (REO)” usually means that the value is calculated on a rare earth oxide basis.

(3) Interpretation points

For hygroscopic products, hydrates, or solvent-containing products, the as-is content and dry-basis content may differ. Moisture, loss on drying, residual solvents, and related items should be considered simultaneously.

Table 3 Common Calculation Basis-Type Purity

Expression	Meaning	Common Applicable Products
dry basis	Calculated on a dry basis, usually after deducting moisture	Hygroscopic products, hydrates, natural products
dry matter	Dry matter basis, similar to dry basis	Biological materials, naturally derived products
anhydrous basis	Calculated on an anhydrous basis	Hydrates, hygroscopic products
based on anhydrous substance	Calculated as an anhydrous substance	Hydrates or water-containing samples
calc. on dry substance	Calculated on dried substance	Pharmacopeial or standardized specifications
metals basis	Calculated on a metals basis	Metal salts, organometallics, catalysts
trace metals basis	Controlled on a trace metals basis	High-purity metal salts, electronic-grade related products
REO	Rare earth oxide basis	Rare earth compounds
carbon basis	Calculated according to carbon content or carbon basis	Carbon materials, carbon nanotubes
active ingredients basis	Calculated on the basis of active ingredients	Mixtures, active ingredient-type products
peptide basis	Calculated on a peptide basis	Peptide products
cyclodextrin basis	Calculated on a cyclodextrin basis	Cyclodextrin derivatives
as P₂O₅/as TiO₂/as WO₃	Converted as specified oxide or elemental form	Inorganic salts, minerals, metal oxide-type products

2.4 Element or Component Content-Type Purity

Element or component content-type purity is used to indicate the content of a target element, functional group, salt-form component, or active component.

(1) Applicable products

It is commonly used for catalysts, supported metal materials, inorganic salts, complexes, ionic liquids, mineral materials, and functional materials.

(2) Main characteristics

This type of labeling does not indicate the chemical purity of a single compound, but rather that a specific element or component reaches the required content.

(3) Interpretation examples

“≥10% Pd” means that the palladium content is not lower than 10%. “≥50% Pt basis” means that the content calculated on a platinum basis is not lower than 50%. “≥85% phosphate (as P₂O₅) basis” means that the phosphate content calculated as P₂O₅ is not lower than 85%.

Table 4 Examples of Element or Component Content-Type Purity

Expression	Meaning
≥10% Pd	Palladium content is not lower than 10%
≥50% Pt basis	Content calculated on a platinum basis is not lower than 50%
≥30% NH₃ basis	Content calculated on an ammonia basis is not lower than 30%
≥85% phosphate (as P₂O₅) basis	Phosphate content calculated as P₂O₅ is not lower than 85%
≥42% K₂S basis	Content calculated on a K₂S basis is not lower than 42%
≥99% (as Se)	Content calculated according to a selenium-related basis is not lower than 99%
≥95% (as C)	Calculated according to carbon content or carbon elemental basis
≥98% (as Cd)	Calculated according to cadmium element or a cadmium-related basis

2.5 Isotopic Abundance-Type Purity

Isotope products commonly use atom% to express isotopic abundance.

(1) Common forms

Examples include “≥99 atom% D,” “≥98 atom% 13C,” “≥95 atom% 15N,” and “≥99 atom% 18O.”

(2) Main meaning

atom% indicates the atomic percentage of the target isotope within the corresponding element and is not equivalent to ordinary chemical purity.

(3) Interpretation points

Isotope products may simultaneously label isotopic abundance and chemical purity. For example, “≥99 atom% D, ≥98%” means that the product meets both the deuterium enrichment requirement and the chemical purity requirement. The two are different quality indicators and should be interpreted separately.

Table 5 Examples of Isotopic Abundance-Type Purity

Expression	Meaning
≥99 atom% D	Deuterium isotopic abundance is not lower than 99 atom%
≥98 atom% 13C	13C isotopic abundance is not lower than 98 atom%
≥95 atom% 15N	15N isotopic abundance is not lower than 95 atom%
≥99 atom% 18O	18O isotopic abundance is not lower than 99 atom%
≥99 atom% D, ≥98%	Both deuterium enrichment and chemical purity requirements are met
≥98 atom% 13C, ≥98 atom% 15N, ≥95%	Multi-element isotopically labeled product with both isotopic abundance and chemical purity labeled

2.6 Isomer, Mixture, and Total Content-Type Purity

Isomer, mixture, and total content-type purity is common in products that are not single-structure substances.

(1) Common expressions

Examples include mixture of isomers, sum of isomers, cis and trans, sum of enantiomers, and Total Diesters.

(2) Main meaning

This type of purity usually indicates that the specified mixed components, total isomer content, or total active components reach the corresponding requirement, rather than indicating that a single structure reaches that percentage.

(3) Interpretation examples

“≥98% (sum of isomers)” means that the total amount of isomers reaches 98%. “≥97% (mixture of isomers)” means that the product exists as an isomeric mixture and that the purity is determined on that mixture basis.

Table 6 Expressions Related to Isomers and Mixtures

Expression	Meaning
mixture of isomers	Isomer mixture
isomeric mixture	Isomer mixture
sum of isomers	Total isomers
mixture of cis and trans	Mixture of cis/trans isomers
predominantly trans	Predominantly trans isomer
Mainly cis	Mainly cis isomer
sum of enantiomers	Total enantiomers
Total Diesters	Total diesters
mixture of polymers	Polymer mixture
oligomer purity	Oligomer purity or oligomer-related purity

2.7 Optical Purity and Chiral Purity

Optical purity and chiral purity are commonly used for chiral compounds.

(1) Core identifier

ee is the abbreviation for enantiomeric excess.

(2) Main meaning

ee reflects the proportional dominance of the target enantiomer relative to the other enantiomer and is not equivalent to ordinary chemical purity.

(3) Interpretation examples

“≥98%, ≥99% ee” means that the product meets both chemical purity of not less than 98% and enantiomeric excess of not less than 99% ee. If only “≥99% ee” is labeled, it only indicates a chiral purity requirement and cannot be directly interpreted as a total content of 99% for the target compound.

Table 7 Expressions Related to Optical Purity

Expression	Meaning
ee	Enantiomeric excess
≥99% ee	Enantiomeric excess is not lower than 99%
≥98%, ≥99% ee	Chemical purity is not lower than 98%, and optical purity is not lower than 99% ee
Chiral Purity	Chiral purity
sum of enantiomers	Total enantiomers

2.8 Purity Related to Biomacromolecules and Functional Activity

For proteins, peptides, enzymes, nucleic acids, and biological material products, purity is often related to electrophoresis, chromatography, enzymatic methods, or activity units.

(1) Common expressions

Examples include “≥95% (SDS-PAGE),” “≥90% (SDS-PAGE & SEC-HPLC),” “≥99% (agarose gel electrophoresis),” and “≥99% (enzymatic).”

(2) Main meaning

This type of purity usually reflects the proportion of the target band, main peak, enzymatic activity, or related component in a specific detection system.

(3) Interpretation points

For protein and enzyme products, applicability should also be judged together with activity, molecular weight, buffer system, stabilizers, and storage conditions.

Table 8 Purity Expressions Related to Biomacromolecules

Expression	Meaning
SDS-PAGE	Purity evaluated according to protein electrophoresis band results
SDS-PAGE & SEC-HPLC	Evaluation combining electrophoresis and size exclusion chromatography
RP-HPLC & SDS-PAGE	Evaluation combining reversed-phase liquid chromatography and protein electrophoresis
agarose gel electrophoresis	Agarose gel electrophoresis, commonly used for nucleic acid products
cellulose acetate electrophoresis	Cellulose acetate membrane electrophoresis
Native-PAGE	Native polyacrylamide gel electrophoresis
WB	Western blot-related detection basis
enzymatic	Enzymatic assay or enzyme-related purity/content

3 Common Abbreviations in Purity Fields

Abbreviation	Explanation
HPLC	High Performance Liquid Chromatography
GC	Gas Chromatography
LC-MS	Liquid Chromatography-Mass Spectrometry
NMR	Nuclear Magnetic Resonance
qNMR	Quantitative Nuclear Magnetic Resonance
SDS-PAGE	Sodium Dodecyl Sulfate-Polyacrylamide Gel Electrophoresis
SEC-HPLC	Size Exclusion Chromatography-High Performance Liquid Chromatography
RP-HPLC	Reversed-Phase High Performance Liquid Chromatography
TLC	Thin Layer Chromatography
HPCE/CE	High Performance Capillary Electrophoresis/Capillary Electrophoresis
UV	Ultraviolet Spectrophotometry
T/titration	Titration
AT	Argentometric Titration
KT	Komplexometric/Complexometric Titration
NT	Nonaqueous Titration
RT	Redox Titration
W	Weight, weight percentage/mass fraction
CP	Chemical Purity
REO	Rare Earth Oxide
ee	Enantiomeric Excess
TGA	Thermogravimetric Analysis
AAS	Atomic Absorption Spectroscopy
CHN	Carbon-Hydrogen-Nitrogen Elemental Analysis
MOF	Metal-Organic Framework
TFA salt	Trifluoroacetic Acid Salt
dry basis	Dry Basis
anhydrous basis	Anhydrous Basis
metals basis	Metals Basis
trace metals basis	Trace Metals Basis
mixture	Mixture
sum of isomers	Sum of Isomers
atom%	Atomic percent for isotopic abundance

4 Principles for Interpreting Purity Labels

4.1 Identify the Value, Method, and Suffix

Purity interpretation should identify the following information simultaneously:

(1) Value

Examples include ≥98%, ≥99%, and 98.5%–101.5%.

(2) Detection method

Examples include HPLC, GC, SDS-PAGE, and NMR.

(3) Calculation basis

Examples include dry basis, anhydrous basis, and metals basis.

(4) Component limitation

Examples include sum of isomers, mixture of isomers, and as P₂O₅.

(5) COA items

The testing items, detection methods, and quality standards for a specific product should be based on its COA.

4.2 Distinguish Method Purity from Absolute Content

Purity given by methods such as HPLC, GC, TLC, and SDS-PAGE is affected by detection conditions, detector response, sample solubility, impurity response, and quantitative approach.

During interpretation, the following points should be noted:

(1) A high main peak proportion does not mean that all impurities are fully included.

(2) Non-UV-responsive impurities, moisture, inorganic salts, and residual solvents may need to be evaluated through other items.

(3) For products where water, salts, inorganic impurities, or residual solvents are important, moisture, ash, residual solvents, elemental analysis, or titration items should be considered together.

4.3 Pay Attention to Deducted Items in Calculation Bases

Expressions such as dry basis, anhydrous basis, and calc. on dry substance indicate that purity has been calculated after considering moisture, loss on drying, or an anhydrous basis.

Key points for interpretation include:

(1) Whether the product is hygroscopic.

(2) Whether the product is a hydrate.

(3) Whether the product contains residual solvents.

(4) Whether moisture, loss on drying, or residual solvents are listed separately in the COA.

4.4 Distinguish Isotopic Abundance from Chemical Purity

In isotope products, atom% describes the degree of isotopic labeling, while ordinary percentage describes chemical purity or main component content.

Common interpretation logic is as follows:

(1) ≥99 atom% D indicates deuterium enrichment and does not mean that the chemical purity of the product is 99%.

(2) ≥99 atom% D, ≥98% means that both isotopic abundance and chemical purity requirements are met.

(3) Products with high isotopic abundance still require attention to chemical purity, isomers, residual solvents, moisture, and other indicators.

4.5 Confirm Mixture and Isomer Limitations

When terms such as mixture, sum, cis/trans, and enantiomers appear, it should first be determined whether the product is a mixture or an isomeric system.

During interpretation, attention should be paid to:

(1) Whether purity is calculated as the total amount of isomers.

(2) Whether the main configuration is specified.

(3) Whether the proportion of a specific isomer is limited.

(4) Whether product selection should consider isomer composition.

4.6 Multiple Parallel Indicators Should All Be Met

Some products label multiple quality indicators simultaneously, for example:

(1) ≥98%, ≥99 atom% D

This means that both chemical purity and isotopic abundance requirements are met.

(2) ≥95% (SDS-PAGE & SEC-HPLC)

This means that evaluation combines both SDS-PAGE and SEC-HPLC bases.

(3) ≥98%, ≥99% ee

This means that both chemical purity and optical purity requirements are met.

For this type of labeling, one indicator alone should not be extracted as the complete explanation of purity.

5 Common Misunderstandings in Purity Descriptions

5.1 Interpreting “≥99%” as Meaning That Total Impurities Are Certainly Below 1%

“≥99%” usually means that the target specification item is not lower than 99%, but whether specific impurities are fully covered depends on the detection method and quality standard.

Common situations include:

(1) HPLC purity does not necessarily cover non-responding impurities.

(2) GC purity does not necessarily cover high-boiling or non-volatile impurities.

(3) Moisture, inorganic salts, and residual solvents may be controlled through other items.

5.2 Interpreting “HPLC Purity” as Total Mass Purity

HPLC purity is commonly used to evaluate the main peak proportion or related impurities, but it does not necessarily cover all invisible impurities.

For the following products, other items should also be considered:

(1) Water-containing products.

(2) Salt-containing products.

(3) Products containing inorganic impurities.

(4) Products containing residual solvents.

(5) Products with obvious detector response differences.

5.3 Interpreting “Metals Basis” as Ordinary Chemical Purity

Metals basis emphasizes calculation based on metal elements or metal components and is commonly used for metal salts, catalysts, rare earth compounds, and high-purity inorganic materials.

This expression is not equivalent to the HPLC or GC purity commonly used for organic small molecules, nor should it be simply interpreted as the mass fraction of a single compound in the sample.

5.4 Interpreting “Atom%” as Mass Percentage

atom% is atomic percentage and is mainly used for isotopic abundance. It indicates the proportion of a specific isotope within the corresponding element, not the mass fraction of the target compound in the product.

5.5 Ignoring Limitations Such as “Mixture,” “Sum,” “Cis/Trans,” and “ee”

Limitations such as mixture, sum, cis/trans, and ee directly change the meaning of purity.

During interpretation, the following should be confirmed separately:

(1) Whether mixture indicates a mixture.

(2) Whether sum indicates total content.

(3) Whether cis/trans involves the ratio of cis/trans isomers.

(4) Whether ee indicates optical purity.

6 Typical Purity Designations and Representative Product Examples

Purity Type	Catalog	Product Name	Grade & Purity	Interpretation Note
Main-content purity	P598617	Pyridine	≥99.9%	Direct percentage-based purity, indicating a high-purity general specification
HPLC purity	D106385	1,3-Dihydroxynaphthalene	≥98%(HPLC)	Determined by High Performance Liquid Chromatography; commonly used for organic small molecules and natural products
SDS-PAGE purity	A754945	Albumin from human plasma	≥95%(SDS-PAGE)	Evaluated by protein electrophoresis band pattern
NMR purity	O290290	2,6-Bis[2,5-bis(3-octylrhodanine)-(3,3-dioctyl-2,2':5,2''-terthiophene)]-4,8-bis((5-ethylhexyl)thiophen-2-yl)benzo[1,2-b:4,5-b']dithiophene	≥99%(NMR)	Determined by Nuclear Magnetic Resonance; applicable to structure confirmation and purity assessment
qNMR purity	T162753	Trihexyl(tetradecyl)phosphonium Dicyanamide	≥95%(qNMR)	Determined by Quantitative Nuclear Magnetic Resonance for quantitative purity analysis
UV purity	P664535	polysachoride of Astragalus mongholicus	≥95%(UV)	Determined by Ultraviolet Spectrophotometry; suitable for products with characteristic UV absorption
Titration purity	T434093	Tris(hydroxymethyl)aminomethane (Tris base)	≥99%(titration)	Determined by titration; commonly used for acid-base, complexometric, redox or volumetric assay specifications
Nonaqueous titration purity	D465687	DL-β-Homoleucine	≥99%(NT)	NT refers to Nonaqueous Titration
Redox titration purity	S131484	Sodium mesoxalate monohydrate	≥98%(RT)	RT refers to Redox Titration
Complexometric titration purity	C473792	Calcium D-saccharate tetrahydrate	≥98.5%(KT)	KT refers to Komplexometric/Complexometric Titration
Argentometric titration purity	E170842	Ethyl benzimidate hydrochloride	≥97%(AT)	AT refers to Argentometric Titration
Titration-related purity	H157412	(4-Hydroxybenzyl)phosphonic Acid	≥98%(T)	T refers to Titration or a titration-related assay
Dry-basis purity	P190904	Phytic acid sodium salt hydrate	≥90%(dry basis)	Calculated on a dry basis, usually applicable to hydrated, hygroscopic or naturally derived products
Anhydrous-basis purity	B463998	2,6-Bis(N-pyrazolyl)pyridine nickel (II) dichloride	≥95% anhydrous basis	Calculated on an anhydrous basis
Metals-basis purity	B302826	Bismuth vanadate	≥98% metals basis	Calculated on a metals basis; not equivalent to ordinary HPLC or GC purity
Trace-metals-basis purity	M431859	Manganese(III) oxide	≥99.5% trace metals basis	Expresses high-purity inorganic material specifications based on trace metal control
Carbon-basis purity	C434645	Carbon nanotube, multi-walled	≥90% carbon basis, D × L 110-170 nm × 5-9 μm	Calculated on a carbon basis, with material dimensions also specified
Elemental-content purity	P111367	Palladium on barium sulfate	≥10% Pd	Indicates palladium content, commonly used for catalysts or supported metal materials
Elemental-basis content purity	T132321	Tetraammineplatinum nitrate	≥50% Pt basis	Calculated on a platinum basis, indicating platinum-content specification
Component-basis content purity	A110371	Ammonium carbonate	AR, 30% NH3 basis(T)	Calculated on an NH3 basis and determined by a titration-related assay
Isotopic abundance purity	C109595	Chloroform-d	≥99.8 atom% D	Indicates deuterium isotopic abundance, not ordinary chemical purity
Isotopic abundance + chemical purity	H344404	5-Hydroxymethyl-2-furaldehyde-¹³C6	≥98 atom%13C,≥98%	Indicates both 13C isotopic abundance and chemical purity
Multiple isotopic abundance + chemical purity	O471890	4-Oxo-TEMPO-d₁₆,¹⁵N, free radical	≥97%,≥95 atom%15N,≥95 atom% D	Indicates chemical purity, 15N abundance and D abundance simultaneously
Isomeric-mixture purity	C345408	Cashmeran	≥98%(mixture of isomers)	Evaluated based on an isomeric mixture
Sum-of-isomers purity	T700809	2-(1,1,2,3,3,3-Hexafluoropropyl)tetrahydrofuran	≥97%(sum of isomers)	Indicates the total amount of isomers reaches the specified level
Optical/chiral purity	P974651	Pyridine, 2,6-bis[(4R,5R)-4,5-dihydro-4,5-diphenyl-2-oxazolyl]-	≥97%,≥99%ee	Indicates both chemical purity and enantiomeric excess
HPLC purity + optical purity	R471753	(R)-(−)-2-Decanol	≥97%(HPLC),≥97%(ee)	Indicates both HPLC purity and enantiomeric excess
Biomacromolecule combined-method purity	Ab131076	Thy1.1/CD90.1 Mouse mAb	Validated, ExactAb™ , Low Endotoxin, Azide Free , ≥95%(SDS-PAGE&SEC-HPLC), See COA	Combines SDS-PAGE and SEC-HPLC to evaluate antibody purity and related components
Electrophoresis-based purity	A754975	Albumin human	Recombinant, ≥99%(agarose gel electrophoresis), expressed in Saccharomyces cerevisiae , aqueous solution, 10% in aqueous buffer	Evaluated by agarose gel electrophoresis, with expression system and solution specification also indicated
Enzymatic-assay purity	N755506	4-Nitrophenyl phosphate disodium salt hexahydrate	for Enzyme immunoassay(ELISA), ≥99%(enzymatic)	Determined by an enzymatic assay, suitable for enzyme reaction or ELISA-related products

For more related articles, please see below:

[1] High-Purity Reagents: Overview and Aladdin Product Selection Guide

[2] What Are Ultra Pure Reagents? – Grade Interpretation, Typical Applications, and Representative Aladdin Products