Skip to Content
Merck
CN

1.06246

1-Naphtholphthalein

pH indicator

Synonym(s):

1-Naphtholphthalein

Sign In to View Organizational & Contract Pricing.

Select a Size

Change View

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:
Technical Service
Need help? Our team of experienced scientists is here for you.
Let Us Assist


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 %


Storage Class

11 - Combustible Solids

wgk

WGK 3

flash_point_f

Not applicable

flash_point_c

Not applicable



Certificates of Analysis (COA)

Search for Certificates of Analysis (COA) by entering the products Lot/Batch Number. Lot and Batch Numbers can be found on a product’s label following the words ‘Lot’ or ‘Batch’.

Already Own This Product?

Find documentation for the products that you have recently purchased in the Document Library.

Visit the Document Library



Global Trade Item Number

SKUGTIN
106246000104022536073897
106246010004022536905334
106246000504022536073903