1.06246
1-Naphtholphthalein
pH indicator
Synonym(s):
1-Naphtholphthalein
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About This Item
Empirical Formula (Hill Notation):
C28H18O4
CAS Number:
Molecular Weight:
418.44
UNSPSC Code:
12352115
EC Index Number:
209-875-5
NACRES:
NA.21
MDL number:
Product Name
1-Naphtholphthalein, indicator
Quality Level
form
solid
loss
≤5% loss on drying, 110°C
visual transition interval
7.1-8.3, pink-brown to blue
mp
253-255 °C
bulk density
350 kg/m3
Amax
470-485 nm (buffer pH 7.1), 649-654 nm (buffer pH 8.3)
storage temp.
2-30°C
SMILES string
O1C(c6c(cccc6)C1=O)(c4c5c(c(cc4)O)cccc5)c2c3c(c(cc2)O)cccc3
InChI
1S/C28H18O4/c29-25-15-13-23(17-7-1-3-9-19(17)25)28(22-12-6-5-11-21(22)27(31)32-28)24-14-16-26(30)20-10-4-2-8-18(20)24/h1-16,29-30H
InChI key
HQHBAGKIEAOSNM-UHFFFAOYSA-N
Analysis Note
Identity (UV/VIS-Spectrum): passes test
Transition range: pH 7.1 - pH 8.3pinkbrownish - blue
Absorption maximum λ 1 (buffer pH 7.1): 470 - 485 nm
Absorption maximum λ 2 (buffer pH 8.3): 649 - 654 nm
Spec. Absorptivity A 1%/1cm (λ1max; 0.01 g/l; buffer pH 7.1; calc. on anhydrous substance): 100 - 180
Spec. Absorptivity A 1%/1cm (λ2max; 0.01 g/l; buffer pH 8.3; calc. on anhydrous substance): 360 - 520
Loss on drying (110 °C): ≤ 5 %
Transition range: pH 7.1 - pH 8.3pinkbrownish - blue
Absorption maximum λ 1 (buffer pH 7.1): 470 - 485 nm
Absorption maximum λ 2 (buffer pH 8.3): 649 - 654 nm
Spec. Absorptivity A 1%/1cm (λ1max; 0.01 g/l; buffer pH 7.1; calc. on anhydrous substance): 100 - 180
Spec. Absorptivity A 1%/1cm (λ2max; 0.01 g/l; buffer pH 8.3; calc. on anhydrous substance): 360 - 520
Loss on drying (110 °C): ≤ 5 %
Storage Class
11 - Combustible Solids
wgk
WGK 3
flash_point_f
Not applicable
flash_point_c
Not applicable
Certificates of Analysis (COA)
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