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Biological Buffers

HEPES

HEPES Specification Comparison PDF Printer friendly PDF version (127 Kb)




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Sigma-Aldrich® HEPES Physical Properties
Synonyms     4-(2-Hydroxyethyl)piperazine-1-ethanesulfonic acid
    N-(2-Hydroxyethyl)piperazine-N'-(2-ethanesulfonic acid)		 HEPES Image
Molecular Formula C8H18N2O4S Beilstein Registry 883043 pKa (at 20) 7.55
Molecular Weight 238.30 MDL Number MFCD00006158 pKa (at 25) 7.48
CAS Number 7365-45-9 EG/EC Number 230-907-9 pKa (at 37) 7.31
Useful pH range 6.8 - 8.2    

Sigma-Aldrich HEPES Specifications Comparison
  H3375 H6147 H4034 H7523 54459 54457
Grade ≥99.5% (titration) ≥99.5% (titration), mouse embryo tested BPC, ≥99.5% (titration), cell culture tested SigmaUltra,
pH 5.0 - 6.5 (20 °C, 1 M in H2O), ≥99.5% (titration)		 BioUltra, ≥99.5% (T) BioUltra, for molecular biology, ≥99.5% (T)
Purity ≥99.5% ≥99.5% ≥99.5% ≥99.5% ≥99.5% ≥99.5%
Reagent Testing
  H3375 H6147 H4034 H7523 54459 54457
Enhanced Quality
Profile Buffers		 X X X X    
260NM     ≤0.05 ≤0.045 ≤0.045 ≤0.045
280NM     ≤0.05 ≤0.035 ≤0.035 ≤0.035
290NM ≤0.05 ≤0.05 ≤0.05      
IR     X      
pH       5.0 - 6.5 (20 °C, 1 M in H2O) 5.0 - 6.5 (25 °C, 1 M in H2O) 5.0 - 6.5 (25 °C, 1 M in H2O)
Molarity            
Osmolality            
Karl Fischer ≤0.1% ≤0.1% ≤0.1% ≤0.1%    
LOD       ≤1.0% ≤0.5% ≤0.5%
Insoluble Matter       filter test filter test filter test
Residue on Ignition       ≤0.1% ≤0.1% ≤0.1%
Life Science Testing
  H3375 H6147 H4034 H7523 54459 54457
Animal Component Free            
Endotoxin     ≤0.1 eu/mg      
SPC     ≤100 cfu/g      
Cell test     X      
Sterility            
RNAse     X     X
DNAse     X     X
Nickase     X      
Protease     X     X
Phosphatase           X
Embryo   X        
Trace Elemental Impurities
  H3375 H6147 H4034 H7523 54459 54457
Sodium(Na)       ≤0.005% ≤0.0050% ≤0.0050%
Chloride(Cl)       ≤0.05% ≤0.0050% ≤0.0050%
Sulfate(SO4)         ≤0.0200% ≤0.0050%
Aluminum(Al)       ≤0.0005% ≤0.0005% ≤0.0005%
Arsenic(As)       ≤0.0001% ≤0.00001% ≤0.00001%
Barium(Ba)       ≤0.0005% ≤0.0005% ≤0.0005%
Bismuth(Bi)       ≤0.0005% ≤0.0005% ≤0.0005%
Calcium(Ca)       ≤0.001% ≤0.0010% ≤0.0010%
Cadmium(Cd)       ≤0.0005% ≤0.0005% ≤0.0005%
Cobalt(Co)       ≤0.0005% ≤0.0005% ≤0.0005%
Chromium(Cr)       ≤0.0005% ≤0.0005% ≤0.0005%
Copper(Cu)       ≤0.0005% ≤0.0005% ≤0.0005%
Iron(Fe)     ≤0.0005% ≤0.0005% ≤0.0005% ≤0.0005%
Potassium(K)       ≤0.005% ≤0.0050% ≤0.0050%
Lithium(Li)       ≤0.0005% ≤0.0005% ≤0.0005%
Magnesium(Mg)       ≤0.0005% ≤0.0005% ≤0.0005%
Manganese(Mn)       ≤0.0005% ≤0.0005% ≤0.0005%
Molybdenum(Mo)       ≤0.0005% ≤0.0005% ≤0.0005%
Nickel(Ni)       ≤0.0005% ≤0.0005% ≤0.0005%
Lead(Pb) ≤0.0005% ≤0.0005% ≤0.0005% ≤0.0005% ≤0.0005% ≤0.0005%
Strontium(Sr)       ≤0.0005% ≤0.0005% ≤0.0005%
Zinc(Zn)       ≤0.0005% ≤0.0005% ≤0.0005%
 
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