Strontium 4-[(5-chloro-4-methyl-2-sulphonatophenyl)azo]-3-hydroxy-2-naphthoate (1:1)

Water solubility

Link to relevant study record(s)

Reference

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2008

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

comparable to guideline study

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Version / remarks:

and ETAD method

Principles of method if other than guideline:

To measure the partition coefficient of pigments utilising the standard OECD Guideline 107 is extremely difficult because of the problems associated with the inherent very low solubilities. The following procedure is used for determining the LogPow of low solubility substances and in particular that of pigments.
The partition coefficient was estimated based on the ratio of the solubilities in n-octanol and in water. The individual solubilities were determined by flask method based on OECD Guideline 105 and the ETAD method.

A defined amount of the pigment (see table 1) was transferred to a 100 ml flask with glass stopper and 60 ml of water (deionised, 18.2 MOcm). This was stirred at 70°C for 2 hours, and then 72 hours in an air conditioned laboratory (T = 23°C). The suspension was then centrifuged (10 000 rpm, 10 min) and filtered once through a standard paper filter, twice through a 0.2 μm membrane filter (Millipore) and twice through a 0.025μm membrane filter (Millipore). If particles were detected in the solution (turbidity), the final filtration step was repeated until a perfectly clear solution was acheived.
The above procedure was conducted in parallel for a total of 2 water (deionised, 18.2 MOcm) samples and of 2 n-octanol (Sigma-Aldrich, spectrophotometric grade) samples.

GLP compliance:

no

Type of method:

flask method

Key result

Water solubility:

>= 100 - <= 120 µg/L

Conc. based on:

test mat. (total fraction)

Incubation duration:

72 h

Temp.:

23 °C

Remarks on result:

other: pH was not determined

Conclusions:

The water solubility of test substance was determined to be 100 - 120 µg/L at 23°C.

Description of key information

100-120 µg/L at 23°C

Additional information

The solubility was determined by flask method based on OECD Guideline 105 and the ETAD method. The quantification was analyzed by UV/Vis absorption.

The non-resin-coated test substance is representative pure substance therefore its data has been chosen as the key study.