Chromate(2-), [4-[(5-chloro-2-hydroxy-3-nitrophenyl)azo]-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-onato(2-)][3-[[1-(3-chlorophenyl)-4,5-dihydro-3-methyl-5-oxo-1H-pyrazol-4-yl]azo]-4-hydroxy-5-nitrobenzenesulfonato(3-)]-, disodium

Partition coefficient

Link to relevant study record(s)

Reference

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Experimental Starting Date: 01 December, 2015; Experimental Completion Date: 08 December, 2015. Study Completion Date: 22 December, 2015.

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

None

Qualifier:

according to guideline

Guideline:

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

Qualifier:

according to guideline

Guideline:

OECD Guideline 117 (Partition Coefficient (n-octanol / water), HPLC Method)

Qualifier:

according to guideline

Guideline:

EU Method A.8 (Partition Coefficient - Shake Flask Method)

Principles of method if other than guideline:

None

GLP compliance:

no

Type of method:

flask method

Partition coefficient type:

octanol-water

Specific details on test material used for the study:

- Identification: FAT FAT 20202/H TE
- Lot. 111
- Appearance: Dark red powder

Analytical method:

photometric method

Key result

Type:

log Pow

Partition coefficient:

0.32

Temp.:

20 °C

Remarks on result:

other: pH is not available

Type:

Pow

Partition coefficient:

2.09

Temp.:

20 °C

Remarks on result:

other: pH is not available

Details on results:

None

Calibration:

Cal Pt.	Standard ng/mL	Area
1	0.725	0.0166
2	1.45	0.0316
3	2.9	0.0642
4	5.8	0.1334
5	14.5	0.3299
6	29.0	0.6660

Preliminary Visual Estimation of the n-octanol solubility

An amount of the test item were stirred with different amounts of n-octanol at room temperature and visually checked for any undissolved particles.

Table 2: Appearance of the test mixtures

Amount of test item in mg	Volume in ml	Total volume in ml	Stirring time	Appearance of mixture
10	1	1	60 min	undissolved
10	1	2	60 min	dissolved

According to this preliminary test the solubility of the test item in n-octanol is about 5 g/l (without correction of the purity).

Calculation of the partition coefficient log Pow from the preliminary tests:

The partition coefficient Pow may be estimated from the saturation concentrations in n-octanol and water by the following equation:

Pow = cs octanol /cs water

s= saturation

With the data obtained from the experiment (cs ~ 5 g/l) and in the preliminary test (water solubility: cs = 10.9 μg/l) the partition coefficient was calculated as log Pow -0.34.

Determination of the solubility in the n-Octanol phase: Flask Methods

 

Experiment	A	B	C	D (blank)
Amount of test item (mg)	1000	1000	1000	--
Stirring time at 30 °C (h)	24	48	72	72
Measured concentration (mg/l)	9.7	4.9	5.1	--
Dilution	0.01ml/10ml	0.01ml/10ml	0.01ml/10ml	--
n-Octanol solubility (g/l)	9.7	4.9	5.1	--

Average experiments A to C: 6.6 g/l

Standard	Measured concentration (mg/l)	% Recovery
Standard 2 (c=1.45 mg/l)	1.5	103.4
Standard 3 (c=2.9 mg/l)	2.9	100
Standard 5 (c=14.5 mg/l)	14.7	101.4

The recovery ranged from 100 % to 103.4 % indicates a sufficient accuracy of the analytical method.

Shake Flask method

A stock solution of the test item was prepared in water (pre-saturated with n-octanol): 35.9 mg / 100 ml.

Three different experiments (double determination) were started with following ratios of octanol / water: A (1:1); B (2:1); C (1:2).

After intensely shaking and subsequent phase separation by centrifugation, the total concentration of the test substance was determined by UV/VIS-spectroscopy (591 nm) at 20 °C in each phase!

Determination of the partition coefficient

Experiement Ratio water/octanol	A Ratio 1:1	B Ratio 2:1	C Ratio 1:2
Stock solution in mg/ml	0.359	0.359	0.359
Stock solution (water) in ml	4	8	4
Octanol (water-sat.) in ml	4	4	8
Dilution (water phase)	1ml/10ml	1ml/10ml	1ml/4ml
Dilution (octanol phase)	0.2ml/5ml	0.2ml/5ml	0.2ml/4ml
Measured concentration water phase (mg/l)	13.7	22.4	17.9
Measured concentration n-octanol phase (mg/l)	13.0	15.6	7.7
Water solubility (g/l)	0.137	0.224	0.072
n-octanol solubility (g/l)	0.326	0.389	0.154
Pow	2.37	1.74	2.15
Log POW	0.37	0.24	0.33

Conclusions:

The n-octanol/water partition coefficient (log Pow) of the test item at 20 °C was determined to be 0.32.

Executive summary:

The n-octanol/water partition coefficient of the test item FAT 20202/H was evaluated in a study conducted according to the EU Method A.8, OECD Guideline 107 and OECD Guideline 117. Flask method was used for this purpose. Based on the findings of the study, the n-octanol/water partition coefficient (log Pow) of FAT 20202/H at 20 °C was determined to be 0.32 (Pow = 2.09).

Description of key information

The n-octanol/water partition coefficient of the test item FAT 20202/H was evaluated in a study conducted according to the EU Method A.8, OECD Guideline 107 and OECD Guideline 117. Flask method was used for this purpose. Based on the findings of the study, the n-octanol/water partition coefficient (log Pow) of FAT 20202/H at 20 °C was determined to be 0.32 (Pow = 2.09).

Key value for chemical safety assessment

Log Kow (Log Pow):

0.32

at the temperature of:

20 °C