Advanced Search

Corning® Buffers

By Corning®
Corning® Buffers

See below for more information on buffering systems.

F = -5 to -20°C
R = 2 to 8°C
A = 15 to 30°C
* = Glass
** = Flexible Media Bag
I = Sterile, IVD Product
NI = Sterile, Research Use Only, Not for IVD Use
IVD = In Vitro Diagnostic
Res = Research Use Only, Not for IVD Use

Buffering Systems

Maintaining the pH of the cell culture medium is critical to cell viability. Most cell lines grow well at pH 7.4 and are inhibited in growth at a pH of 6.8. Glucose is usually the sugar included in media and is metabolized by the cells very rapidly, at a rate faster than it is needed. Byproducts of this metabolism include pyruvic and lactic acids and CO2. One way to reduce the amount of lactic acid is to replace the glucose with other sugars such as galactose or fructose. These are utilized at a slower rate, but also result in a slower rate of cell growth. This replacement, however, can slow down the onset of a pH shift.

The bicarbonate and carbon dioxide buffering system is most commonly used to maintain physiological pH (7.2-7.4) of a culture. Bicarbonate is a weak buffer with a pKa of 6.1 making a pH range of 7.2-7.6 more difficult to prevent rapid pH changes. Bicarbonate, however, is less expensive than other buffers, is non-toxic, and has nutritional value.

Bicarbonate/CO2 Systems

The amount of dissolved CO2 in water is dependent on the amount of atmospheric CO2 and the temperature. Increasing CO2 tension in the absence of sodium bicarbonate leaves the medium acidic.

H2O + CO2 ↔ H2CO3 ↔ H+ + HCO3

The addition of sodium bicarbonate in the presence of CO2 will drive the equation to the left to allow for an equilibrium to be achieved and the pH maintained at 7.2-7.4.

NaHCO3 ↔ Na+ + HCO3

Although CO2 is produced by growing cells, it is not produced in a high enough level when growing at a low cell density or during lag phase to maintain an optimal pH. Use of a CO2 incubator is a good way to control the CO2 tension and the temperature. Depending on the type of CO2 incubator used, calibration should be regularly performed to ensure the correct CO2 tension is being maintained.

Organic Systems

Organic buffers such as HEPES (N-2-hydroxyethylpiperazine-N'-2-ethanesulphonic acid) do not require elevated levels of CO2 and provide an alternative to the use of bicarbonate for buffering. Unlike the low pKa of bicarbonate, HEPES has a pKa of 7.66 making it a much stronger buffer in the pH 7.2-7.6 range. Disadvantages to using this zwitterionic buffer, however, are cost, toxicity, and lack of nutritional value. Recommended usage of HEPES is at concentrations of 10-25 mM; toxicity to cells can occur at a concentration over 100 mM. HEPES may be used in addition to bicarbonate for added buffering capacity. It is important to maintain sufficient bicarbonate in the medium for nutritional purposes even if HEPES is being used as the primary buffer.

NOTE: Most powdered cell culture media are deficient in sodium bicarbonate. Please refer to the formulations to determine the amount of bicarbonate to supplement.

                 
Cat.No. Name Pkg Size EA     PK    
23-25-035-CI Sodium Bicarbonate, 7.5% (w/v) solution 6-pack/100mL bottles       $131.63
1/PK
Add To Favorites
23-25-060-CI HEPES, 1M solution 6-pack/100mL bottles       $370.13
1/PK
Add To Favorites
23-61-034-RM HEPES, powder,MW 238.3 100gm $129.67
1/EA
Add To Favorites      
23-61-034-RO HEPES, powder, MW 238.3 500gm $218.01
1/EA
Add To Favorites      
23-61-034-RR HEPES, powder, MW 238.3 1kg $652.60
1/EA
Add To Favorites      
23-61-065-RO Sodium Bocarbonate, powder,MW 84.01 500gm $87.99
1/EA
Add To Favorites      
23-61-065-RR Sodim Bicarbonate, powder, MW 84.01 1kg $215.66
1/EA
Add To Favorites      

The following items have been added to your cart:

Choose a favorite list for this item:

Catalog Number Description Price
$

Returns/Order support

Please fill out the form below if you want to request order support from Krackeler Scientific.


Quick Order

* Required


New Year Price Updates

We are currently working diligently to update our website pricing information for the New Year. If you place an order, you will be acknowledged with any corrected pricing. If you'd like the most current information sooner, please don't hesitate to drop us an email or give us a call and we'd be happy to assist. Thank you for your patience while we are updating.

800-334-7725
office@krackeler.com


Play Video

To Request a Quote

  1. Search or Browse for items and add to them to your Shopping Cart.
  2. Click the "Request Quote" button at the bottom of the Shopping Cart page.
  3. Fill out required fields.
  4. Optionally you can convert to standard checkout mode by choosing a payment type.
  5. Click "Request Quote" at the bottom of the page.

You will be contacted with a quote.

To Order From a Quote

  1. Register and login to the website.
  2. Receive a quote from your sales representative or customer service.
  3. Have your copy of the quote in hand.
  4. Visit our quote module to search for your quote.
Back to Top