CAPS (buffer)

CAPS is the common name for 3-(Cyclohexylamino)-1-propanesulfonic acid, a chemical used as buffering agent in biochemistry. The similar substance N-cyclohexyl-2-hydroxyl-3-aminopropanesulfonic acid (CAPSO) is also used as buffering agent in biochemistry. Its useful pH range is 9.7-11.1.

CAPS^[1]

Names
Preferred IUPAC name 3-(Cyclohexylamino)propane-1-sulfonic acid
Identifiers
CAS Number	1135-40-6 Y
3D model (JSmol)	Interactive image
ChemSpider	63979 Y
DrugBank	DB02219
ECHA InfoCard	100.013.175
EC Number	214-492-1
PubChem CID	70815
UNII	4W981O1LXP
CompTox Dashboard (EPA)	DTXSID3061554
InChI InChI=1S/C9H19NO3S/c11-14(12,13)8-4-7-10-9-5-2-1-3-6-9/h9-10H,1-8H2,(H,11,12,13) N Key: PJWWRFATQTVXHA-UHFFFAOYSA-N N InChI=1/C9H19NO3S/c11-14(12,13)8-4-7-10-9-5-2-1-3-6-9/h9-10H,1-8H2,(H,11,12,13) Key: PJWWRFATQTVXHA-UHFFFAOYAU
SMILES C1CCC(CC1)NCCCS(=O)(=O)O
Properties
Chemical formula	C9H19NO3S
Molar mass	221.32 g/mol
Melting point	>300 °C
Acidity (pKa)	10.4[2]
Hazards
GHS labelling:
Pictograms
Signal word	Warning
Hazard statements	H302, H315, H319, H335
Precautionary statements	P261, P264, P270, P271, P280, P301+P312, P302+P352, P304+P340, P305+P351+P338, P312, P321, P330, P332+P313, P337+P313, P362, P403+P233, P405, P501
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references

See also

• CHES
• Good's buffers § List of Good's buffers

References

1. CAPS at Sigma-Aldrich
2. Esplin, Taran L.; Cable, Morgan L.; Gray, Harry B.; Ponce, Adrian (2010). "Terbium-Macrocycle Complexes as Chemical Sensors: Detection of an Aspirin Metabolite in Urine Using a Salicylurate-Specific Receptor Site". Inorganic Chemistry. 49 (10): 4643–4647. doi:10.1021/ic1003066.
   Tabata, Masaaki; Habib, Ahsan; Watanabe, Keiichi (2005). "DNA Cleavage by Good's Buffers in the Presence of Au(III)". Bulletin of the Chemical Society of Japan. 78 (7): 1263–1269. doi:10.1246/bcsj.78.1263.