tetrasodium 3-amino-4-{[4-({4-fluoro-6-[phenyl(2-{[2-(sulfonatooxy)ethyl]sulfonyl}ethyl)amino]-1,3,5-triazin-2-yl}amino)-2-sulfonatophenyl]diazenyl}-5-hydroxynaphthalene-2,7-disulfonate

Partition coefficient

Link to relevant study record(s)

Reference

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From September 22, 2004 to October 07, 2004

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 107 (Partition Coefficient (n-octanol / water), Shake Flask Method)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method A.8 (Partition Coefficient)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

shake-flask method to: flask method

Partition coefficient type:

octanol-water

Analytical method:

high-performance liquid chromatography

Key result

Type:

log Pow

Partition coefficient:

< -2

Temp.:

20 °C

Remarks on result:

other: pH not determined

Details on results:

Octanol solubility of the test substance (average of three experiments and without correction of purity): 10.69 µg/L.

The saturation concentration of the test substance in water was determined in project 20040776.02 to be 475.3 g/L (without correction for the purity).

From the individual solubilities the log Kow was calculated to be -8.7

Preliminary Visual Estimation of the n-Octanol Solubility

An amount of the test substance was stirred with increasing amounts of n-octanol at room temperature.

 

Table: Appearance of the test mixtures 

Amount of the test substance in mg	Total volume in mL	Stirring time (h)	Appearance of mixture	Solubility (mg/L)
15.63	50	0.5	undissolved	<312.6
15.63	100	0.5	undissolved	<156.3
15.63	150	0.5	undissolved	<104.2
15.63	200	0.5	undissolved	<78.2
15.63	250	0.5	undissolved	<62.5
15.63	300	1.5	undissolved	< 52.1

 

The solubility of the test substance in n-octanol was below 52.1 mg/L (without correction for the purity).

 

Calculation of the Partition Coefficient log K_ow from the preliminary tests

The partition coefficient was calculated as log K_owlower than - 2. Due to this fact the partition coefficient n-octanol/water of the test substance at room temperature was estimated from its solubility in water and in n-octanol.

 

Flask-Method

Table: n-Octanol solubility of the test substance- experiments A to D

 

Experiment	A	B	C	D (blank)
Amount of test substance (mg)	15.95	18.67	16.04	-
Aliquot for extraction (mL)	10	10	10	10
Volume of water (mL)	2	2	2	2
Measured concentration (µg/L)	47.7/46.8	74.6/70.0	44.8/36.8	-
Mean concentration (µg/L)	47.3	72.3	40.8	-
n-octanol solubility (µg/L)	9.45	14.46	8.16	-

  

Average experiments A to C (without correction for the purity): 10.69 µg/L

Standard deviation: 3.32 µg/L

Relative standard deviation: 31%

 

Concentrations of standards for recheck

 

Standard	Measured concentration (µg/L)	%Recovery
Standard K (c= 123.3 µg/L)	137.8	112
10 mL experiment A + 0.1 mL standard D (2466 µg/L) extracted with 2 mL water (c = 164.7µg/L)	143.0/147.8	88
Standard K (c = 123.3 µg/L)	139.3	113
Standard K (c = 123.3 µg/L)	131.0	106

 

Recoveries of the 'Recheck samples' ranged between 88% and 113%, indicating a good accuracy of the analytical method.

 

The saturation concentration of the test substance in water was determined in project 20040776.02 to be 475.3 g/L (without correction for the purity).

 

Conclusions:

Under the study conditions, the partition coefficient (log Kow) n-octanol/water of the test substance at room temperature was estimated to be <-2.

Executive summary:

A study was conducted to determine the partition coefficient of the test substance according to OECD guideline 107 and EU method A.8, in compliance with GLP.

 

Partition coefficient was determined according to the flask-shaking method. Samples were prepared in aqueous and n-octanol phases. After sample preparation, the concentration of the test substance was determined by HPLC. The saturation concentration of the test substance in water was determined to be 475.3 g/L and the octanol solubility (µg/L) was found to be 10.69 µg/L.

 

Under the study conditions, the partition coefficient n-octanol/water of the test substance at room temperature, performed according to the flask method (individual solubilities in water and n-octanol), was determined to be <-2.

Description of key information

The partition coefficient n-octanol/water (log Kow) of the test substance at room temperature was estimated to be <-2 (Schminke, 2004).

Key value for chemical safety assessment

Log Kow (Log Pow):

-2

at the temperature of:

20 °C