2-(4-Hydroxyphenylazo)benzoic acid

matrix substance for MALDI-MS, ≥99.5% (HPLC), Ultra pure

HBABA, HABA, 4′-Hydroxyazobenzene-2-carboxylic acid, 2-(4′-Hydroxybenzeneazo)benzoic acid
Linear Formula:
CAS Number:
Molecular Weight:
Beilstein/REAXYS Number:
EC Number:
MDL number:
PubChem Substance ID:
Pricing and availability is not currently available.

Quality Level


matrix substance for MALDI-MS


≥99.5% (HPLC)


204-208 °C (lit.)
204-208 °C


ethanol: 20 mg/mL, clear

cation traces

Ag: ≤1.0 mg/kg
Al: ≤1.0 mg/kg
B: ≤1.0 mg/kg
Ba: ≤1.0 mg/kg
Be: ≤1.0 mg/kg
Bi: ≤1.0 mg/kg
Ca: ≤1.0 mg/kg
Cd: ≤1.0 mg/kg
Co: ≤1.0 mg/kg
Cr: ≤1.0 mg/kg
Cu: ≤1.0 mg/kg
Fe: ≤1.0 mg/kg
Ge: ≤1.0 mg/kg
K: ≤5 mg/kg
Li: ≤1.0 mg/kg
Mg: ≤1.0 mg/kg
Mn: ≤1.0 mg/kg
Na: ≤5 mg/kg
Ni: ≤1.0 mg/kg
Pb: ≤1.0 mg/kg
Sn: ≤1.0 mg/kg
Sr: ≤1.0 mg/kg
Tl: ≤1.0 mg/kg
Zn: ≤1.0 mg/kg


≥2000 at 337 nm (mol. absorption)

SMILES string




InChI key


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Hazard Statements

Precautionary Statements

Target Organs

Respiratory system

Personal Protective Equipment

dust mask type N95 (US),Eyeshields,Gloves


NONH for all modes of transport

WGK Germany


Flash Point(F)

Not applicable

Flash Point(C)

Not applicable

Certificate of Analysis
Certificate of Origin
Mehmet Cinar et al.
Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy, 105, 80-87 (2013-01-09)
The optimized geometrical structure, vibrational and electronic transitions, chemical shifts and nonlinear optical properties of 2-(4-hydroxyphenylazo)benzoic acid (HABA) compound were presented in this study. The ground state geometrical structure and vibrational wavenumbers were carried out by using density functional (DFT/B3LYP)...
Ting Deng et al.
Biosensors & bioelectronics, 21(8), 1545-1552 (2005-08-09)
A quartz crystal microbalance (QCM) sensor was proposed for the detection of small molecule biotin based on the mixed self-assembled monolayer (SAM) of thiols on gold substrate and the bioaffinity difference between an analyte (biotin) and an analogue compound (HABA)...
Kenneth Kam-Wing Lo et al.
Chemistry (Weinheim an der Bergstrasse, Germany), 12(5), 1500-1512 (2005-11-24)
Six luminescent cyclometalated iridium(III)-dipyridoquinoxaline and -dipyridophenazine complexes [Ir(ppy)2(N-N)](PF6) (Hppy = 2-phenylpyridine; N-N = dipyrido[3,2-f:2',3'-h]quinoxaline, dpq (1); 2-n-butylamidodipyrido[3,2-f:2',3'-h]quinoxaline, dpqa (2); 2-((2-biotinamido)ethyl)amidodipyrido[3,2-f:2',3'-h]quinoxaline, dpqB (3); dipyrido[3,2-a:2',3'-c]phenazine, dppz (4); benzo[i]dipyrido[3,2-a:2',3'-c]phenazine, dppn (5); 11-((2-biotinamido)ethyl)amidodipyrido[3,2-a:2',3'-c]phenazine, dppzB (6)) have been designed as luminescent intercalators for DNA and...
Kenneth Kam-Wing Lo et al.
Inorganic chemistry, 43(17), 5275-5282 (2004-08-18)
Two luminescent ruthenium(II) polypyridine complexes containing a biotin moiety [Ru(bpy)(2)(L1)](PF(6))(2) (1) and [Ru(bpy)(2)(L2)](PF(6))(2) (2) (bpy = 2,2'-bipyridine; L1 = 4-(N-((2-biotinamido)ethyl)amido)-4'-methyl-2,2'-bipyridine; L2 = 4-(N-((6-biotinamido)hexyl)amido)-4'-methyl-2,2'-bipyridine) have been synthesized and characterized, and their photophysical and electrochemical properties have been studied. Upon photoexcitation, complexes...
Xiaoze Jiang et al.
Bioconjugate chemistry, 20(5), 994-1001 (2009-05-01)
Quantum dots (QDs) containing surface carboxylic groups have been successfully modified using biotinylated glycopolymer and carbohydrate/biotin reagents via EDC coupling. The biotinylated glycopolymer was synthesized in controlled dimension via the reversible addition-fragmentation chain transfer (RAFT) polymerization of the three monomers...

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