Ellman's reagent, 10 mM DTNB solution for thiol assay at 412 nm, BZ355 – BioChemazone 500 mL bottle

Ellman’s Reagent, 10 mM DTNB Solution – Ready-to-Use Thiol (–SH) Assay Reagent (BZ355)

Price range: $120.00 through $575.00

Ellman’s Reagent, 10 mM DTNB Solution (5,5′-Dithiobis(2-nitrobenzoic acid)) BZ355

Product Code: BZ355
Manufacturer: Biochemazone
Available Pack Sizes: 100 mL, 200 mL, 500 mL, 1 L
Custom Bulk Quantities Available

Product Overview

Biochemazone Ellman’s Reagent BZ355 is a ready-to-use 10 mM solution of DTNB (5,5′-dithiobis(2-nitrobenzoic acid)) for measuring free thiol (–SH) groups in proteins, peptides and small molecules such as cysteine and glutathione.

DTNB reacts with a free thiol to release one molecule of the yellow TNB2− anion, which is read at 412 nm (molar extinction coefficient 14.15 mM−1 cm−1). The 10 mM stock is simply diluted into your assay buffer – no weighing of DTNB powder. The same chemistry underpins the Ellman acetylcholinesterase assay, where acetylthiocholine hydrolysis is followed with DTNB.

Each batch is prepared under Biochemazone’s ISO 9001 / GMP quality system.

Key Features & Benefits

✅ 10 mM DTNB Stock – Ready to dilute, no weighing
✅ Fast Read at 412 nm – 2-minute reaction, yellow TNB product
✅ Quantitative – ε412 = 14.15 mM−1 cm−1
✅ Plate or Cuvette – Works in microplates and spectrophotometers
✅ AChE Assays – Classic Ellman cholinesterase method
✅ 100 mL to 1 L – Plus custom bulk volumes
✅ Quality-Controlled – Consistent batch-to-batch performance
✅ Made in Canada – Manufactured under ISO 9001 / GMP quality systems

Applications

🧪 Protein & Peptide Chemistry
• Free-thiol (cysteine) quantification
• Checking disulfide reduction
• Monitoring thiol–maleimide and PEGylation reactions

🧬 Biochemistry & Pharmacology
• Acetylcholinesterase and butyrylcholinesterase activity (Ellman method)
• Glutathione and cysteine measurement
• Enzyme inhibitor screening

🔬 Analytical Chemistry
• Thiol content of foods, drugs and materials
• Teaching laboratories

Usage Areas

  • Protein chemistry and bioconjugation laboratories
  • Pharmacology and toxicology laboratories
  • Neuroscience (cholinesterase) research groups
  • Food and pharmaceutical analysis laboratories
  • Academic and teaching laboratories

Composition (per litre)

ComponentConcentrationAmount per litre
DTNB (5,5′-dithiobis(2-nitrobenzoic acid), CAS 69-78-3)10 mM3.96 g
Solvent—to 1 L (as stated on the CoA)

Molecular weight of DTNB: 396.3 g/mol. Dilute 100-fold in 0.1 M Tris-HCl, pH 7.5 for a 0.1 mM working solution.

Assay Protocol (1 mL cuvette)

StepWhat to do
1. Working solutionDilute BZ355 100-fold with 0.1 M Tris-HCl, pH 7.5, to give 0.1 mM DTNB.
2. SampleMix 950 µL working solution with 50 µL sample (thiol below 0.5 mM).
3. BlankMix 950 µL working solution with 50 µL 0.1 M Tris-HCl, pH 7.5.
4. Incubate2 minutes at room temperature.
5. ReadMeasure absorbance at 412 nm against the blank.
6. CalculatemM –SH = A412 ÷ (path length × 14.15) × 20 × sample dilution factor.

The factor 20 accounts for 50 µL sample in a 1 mL assay. Adapt volumes for microplates or use a cysteine standard curve.

Typical Properties

  • Appearance: Clear, pale yellow liquid
  • DTNB concentration: 10 mM
  • Detection: Absorbance at 412 nm
  • Light-sensitive: keep protected from light

Available Formulations

  • Ellman’s reagent 10 mM DTNB (this product, BZ355)
  • 1 M Tris-HCl pH 7.4 (BZ217)
  • 1 M Tris-HCl pH 8.0, sterile (BZ214)
  • 0.1 M phosphate buffer pH 7.4 (BZ204)

Storage, Shelf Life & Transportation

  • Storage Temperature: 2–30 °C, protected from light
  • Shelf Life: 1 year for unopened bottles
  • Transportation: Room temperature (ambient shipping)
  • Version with Preservatives: Available on request
  • Powder Version: Available on request
  • Keep tightly closed; prepare working dilutions fresh
  • A strong yellow colour in the stock indicates degradation – check against a blank

Customization Options

  • Other DTNB concentrations
  • Ready-to-use 0.1 mM working solution in Tris-HCl pH 7.5
  • DTNB powder and cysteine standards
  • Bulk containers

Ordering Information

BZ355 is available in standard laboratory sizes or OEM/bulk supply formats.

📄 MSDS, Technical Datasheet, and Certificate of Analysis (CoA) available upon request
Email: info@biochemazone.com
Website: www.biochemazone.com

⚠️ For laboratory research use only. Not for human or animal injection or therapeutic use.

Description

Product overview

Ellman’s Reagent (BZ355) is a ready-to-use 10 mM DTNB solution for measuring free thiol groups at 412 nm and for Ellman cholinesterase assays.

  • Catalogue no.: BZ355
  • Active: DTNB, 10 mM
  • Detection: 412 nm (TNB2−)
  • Pack sizes: 100 mL, 200 mL, 500 mL, 1 L
  • Storage: 2–30 °C, protected from light
  • Shelf life: 1 year (unopened bottle)
  • On request: Version with preservatives; powder version
  • Transportation: Room temperature
  • Use: Laboratory research use only

See also: 1 M Tris-HCl pH 7.4 (BZ217) · 1 M Tris-HCl pH 8.0 (BZ214) · 0.1 M phosphate buffer (BZ204)

Frequently asked questions

How does Ellman’s reagent work?

DTNB reacts with each free thiol (–SH) group and releases one yellow TNB2− ion, which absorbs strongly at 412 nm.

What buffer should I dilute it in?

The standard protocol dilutes it 100-fold in 0.1 M Tris-HCl, pH 7.5, giving 0.1 mM DTNB. Phosphate buffers at pH 7.5–8.0 with 1 mM EDTA also work well.

How do I calculate thiol concentration?

mM thiol = A412 ÷ (path length × 14.15) × 20 × dilution factor, where 20 accounts for the 50 µL sample in a 1 mL assay. A cysteine standard curve can also be used.

Can I use it for acetylcholinesterase assays?

Yes. In the Ellman method, AChE releases thiocholine from acetylthiocholine, which then reacts with DTNB and is read at 412 nm.

How should Ellman’s reagent be stored?

Store at 2–30 °C, tightly closed and protected from light. Unopened bottles have a 1-year shelf life and ship at room temperature.

Ellman’s Reagent (10 mM DTNB)

Ellman’s Reagent (10 mM DTNB) composition and customer’s specified configurations can be delivered upon request. DTNB Concentration, Buffer, pH Value, Container Size, and Contents of the reagent are customizable.
Contact us for Customization: info@biochemazone.com
Transportation and storage: Transportation at room temperature, storage at 2–30 ℃
We provide shipping facilities worldwide.

quality-assurance
Quality-Control-Approved
iso
iata
dubai-accreditation
iaf

Documents

Certificates of Analysis are issued per production batch. Please add the lot number or your order number to the request (catalogue no. BZ355 is filled in for you).

Additional information

Pack Size

100 mL, 200 mL, 500 mL, 1 L

Important Notes

  • Research Use Only: Biochemazone™ materials are intended strictly for research and development purposes in laboratory and industrial settings.
  • No Refunds or Exchanges: All sales are final. Biochemazone™ does not permit exchanges or offer refunds under any circumstances.
  • Customs & Import Responsibilities: Customs clearance, duties, taxes, and tariffs are the sole responsibility of the consignee/importer. Biochemazone™ is not liable for delays, rejections, or any additional costs incurred during the customs process, and such issues will not justify order cancellations or refunds.
  • Order Cancellations: Once an order is placed, it cannot be cancelled. No refunds will be issued for cancelled or undelivered orders.
  • Indemnification: The buyer agrees to indemnify and hold harmless Biochemazone™, its affiliates, and personnel from any claims, damages, liabilities, or expenses arising from the use of its products or services.

Terms & Conditions: All orders and communications are subject to Biochemazone™’s standard Terms & Conditions.

Disclaimer: Images and colors of the formulation displayed are for portrayal purposes only. Actual color and consistency may vary.

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