Sodium 4-[4-[[2-methyl-4-[[(p-tolyl)sulphonyl]oxy]phenyl]azo]anilino]-3-nitrobenzenesulphonate

Partition coefficient

Link to relevant study record(s)

Reference

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Study period:

May from 19th to 23rd, 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

test procedure in accordance with generally accepted scientific standards and described in sufficient detail

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

adopted July 27, 1995

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

flask method

Partition coefficient type:

octanol-water

Analytical method:

high-performance liquid chromatography

Type:

log Pow

Partition coefficient:

1.03

Temp.:

20 °C

pH:

6.77

Details on results:

The nine log Pow values were within a range of ± 0.3 units.

The calibration curve was prepared on the day of determination of the partition coefficient and the calibration curve was constructed applying linear regression.

The pH of the water used was 6.77.

Partition coefficients measured

Ratio of solvents (n-octanol : water)	Pow	Mean	log Pow	Mean
1 : 1	11.7389	11.0484	1.07	1.04
	10.8628		1.04
	10.5434		1.02
1 : 2	15.1812	14.2270	1.18	1.15
	13.423		1.13
	14.0769		1.15
2 : 1	8.4578	8.0230	0.93	0.9
	7.8632		0.9
	7.7480		0.89
Mean all ± 95 % confidence interval	-	11.0995 ± 2.1118	-	1.03 ± 0.084
RSD %	-	25	-	11

Results of the determination of test tem concentrations

Ratio of solvents (n-octanol : water)	Measured concentration of Test Item (µg/ml)		pH	Measured concentration of Test Item (µg/ml)
	In Aqueous phase	Mean		In n-octanol phase	Mean
1 : 1	14.47	14.65	6.79	173.39	171.92
	14.82			170.45
	14.97	15.17	6.78	156.95	164.84
	15.38			172.72
	15.15	15.16	6.79	158.94	159.88
	15.18			160.82
Mean	14.99		6.79	165.55
RSD%	2			3.7
Measured test item µg	112.46			1241.59
Total nominal quantity of test item	1354.1 µg
Total quantity of test item	1276.1 µg		Recovery	106 %
1 : 2	25.99	25.81	6.92	213.22	218.29
	25.63			223.35
	25.82	25.56	6.88	210.32	208.88
	27.31			207.43
	26.49	26.84	6.88	205.7	207.96
	27.2			210.23
Mean	26.4		6.89	211.71
RSD%	2			2.7
Measured test item µg	264.05			1058.55
Total nominal quantity of test item	1322.6 µg
Total quantity of test item	1276.1 µg		Recovery	104 %
2 : 1	9.47	8.47	6.72	136.1	135.73
	8.41			135.36
	9.39	8.41	6.72	124.41	130.4
	10.04			136.39
	8.63	9.01	6.72	130.39	126.84
	9.39			123.28
Mean	9.22		6.72	130.99
RSD%	4.6			3.4
Measured test item µg	46.11			1309.88
Total nominal quantity of test item	1356.0 µg
Total quantity of test item	1276.1 µg		Recovery	106 %

Conclusions:

log Pow: 1.03 ± 0.084 at 20 °C and pH 6.77

Executive summary:

The partition coefficient of test item was determined by shake-flask method following the procedures outlined into the OECD guideline 107. The experiments were carried out applying volume ratios and quantities of the test substance depending on expected partition and the LOQ of the analytical method in both phases. Three parallel tests were carried out at all solvent ratios.

In conclusion, the partition coefficient (Pow) of test item in n-octanol-water was determined to be 11.0995 ± 2.1118 (95 % confidence interval) using shake flask method. The nine log Pow values were within a range of ± 0.3 units.

Conclusion

Pow: 11.0995 ± 2.1118 at 20 °C and pH 6.77

log Pow: 1.03 ± 0.084 at 20 °C and pH 6.77

Description of key information

log Pow: 1.03 ± 0.084 at 20 °C and pH 6.77

Key value for chemical safety assessment

Log Kow (Log Pow):

1.03

at the temperature of:

20 °C

Additional information

OECD 107 - Flask method