Product Category


ICH-Q7 GMP Manufactured Product

HEPES, Free Acid, Ultra-Low UV, LBLE
GMP Excipient Grade

Low Bioburden, Low Endotoxin, GMP Manufactured

Product Code: HEPE-3252

Intended For Use As An Excipient

HEPES is a zwitterionic buffer used to maintain pH of media used in cell cultures. It is one of Good’s twelve buffers that has a pKa value similar to its pH value making it an ideal buffer for pH maintenance. It has only one restriction, it interferes with the Folin protein assay. This buffer can form radicals so it is not suitable for redox studies. HEPES is used as a Good’s buffer because it has low UV absorptivity, minimal reactivity, stable pH and is soluble in water.


Product Specifications

Absorbance (1M)

250 nm

260 nm

280 nm

0.0500 a.u.
0.0400 a.u.
0.0400 a.u.
Absorbance (0.05M)

250 nm

260 nm

280 nm

 0.0500 a.u.
0.0500 a.u.
0.0500 a.u.
Appearance and Color  
White / Crystals
Assay, Dried Basis  
99.5% min.
0.005% max.
≤ 5 EU/g




 None Detected

None Detected

None Detected

Heavy Metals (as Lead)  
1 ppm max.
Identification (IR)  
Passes Test
Insoluble Matter  
≤ 0.01% max.

Microbial Content


≤ 50 CFU/g
≤ 50 CFU/g

pH (1% Soln.)

4.7 – 5.6


7.45 – 7.65
Residue on Ignition  
0.1% max.
Solubility (1% soln.)  
Pass / Clear Solution
Solubility (0.05M) Passes Test
0.005% max.
Trace Metals

Arsenic (As)

Copper (Cu)

Iron (Fe)

Lead (Pb)

5 ppm max.

5 ppm max.

5 ppm max.

5 ppm max.

Water Content (Karl Fischer) 0.5% max.
Printable Version
List of C of As files
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CAS #: 7365-45-9

Formula: C8H18N2O4S

Sol. In H2O (g/L): 400

F.W.: 238.30 g/mol

pH @ 20°C: 5.0 - 6.5

Useful pH: 6.8 - 8.2

pKa @ 20˚C: 7.55

General Product Description:

  • The manufacturing of HEPES, HEPE-3252 is performed at BioSpectra’s Bangor and Stroudsburg, PA facilities utilizing multi-use equipment. Equipment used in the manufacturing of HEPE-3252 is cleaned in accordance with BioSpectra’s Process Cleaning Validation Master Plan.
  • HEPES is a White Crystalline Product.
  • Molecular Formula: C8H18N2O4S
  • Molecular Weight: 238.30 g/mol.
  • CAS Number: 7365-45-9.
  • There are no known major food allergens (as defined by FDA and WHO) in the manufacture of this product.
  • BioSpectra certifies that all HEPES HEPE-3252 manufactured at BioSpectra and its raw materials are not derived from or come in contact with animal parts, products, and/or byproducts.
  • HEPES manufactured at BioSpectra and any raw materials used in the manufacture of HEPES at BioSpectra are not subject to genetic modification.
  • Synonyms: N-(2-Hydroxyethyl)piperazine-N’-2- ethanesulfonic acid, 2-[4-(2-hydroxyethyl)piperazin-1-yl] ethanesulfonic acid.


ELEMENTAL IMPURITIES: This product complies with ICHQ3D, USP <232> and USP <233> requirements for Elemental Impurities.

RESIDUAL SOLVENTS: Based on the manufacturing process and the controlled handling, storage and analysis of this product, this product complies with the requirements and specifications listed in the current USP method <467> Tables 1, 2, 3, or 4.

GMP Compliance:

Bio Excipient Grade HEPES, HEPE-3252 is suitable for use as an excipient. It is manufactured in accordance with the ICH-Q7 Good Manufacturing Practice Guide. This grade of HEPES is not suitable to be used as an Active Pharmaceutical Ingredient, Drug Product or Household Item.

Retest Date:

The recommended retest period for HEPES is two years from the date of manufacture.

Storage and Shipping Conditions:

Ship and store in ambient temperature. Store in a clean and dry area. Store in the original container.

Package Sizes:

10kg, 25kg and 50kg pails.

Additional Packaging Information