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Partition coefficient

Link to relevant study record(s)

Reference

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Study period:

18-10-2019 to 21-01-2020

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

Guideline study performed under GLP. All relevant validity criteria were met.

Qualifier:

according to guideline

Guideline:

OECD Guideline 123 (Partition Coefficient (1-Octanol / Water), Slow-Stirring Method)

Deviations:

no

Qualifier:

equivalent or similar to guideline

Guideline:

EU Method A.23 Partition Coefficient (1-Octanol/Water): Slow-Stirring Method

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

inspected: July 2016 ; signature: January 2017

Type of method:

slow-stirring method

Partition coefficient type:

octanol-water

Analytical method:

gas chromatography

mass spectrometry

Type:

log Pow

Partition coefficient:

8.146

Temp.:

25 °C

pH:

ca. 5.8

Remarks on result:

other: log Pow: 8.146 ± 0.249

Table 1.0: Partition Coefficient Results

Replicate	Test	Measured concentration		POW	Log POW
number	Duration [h]	in n-octanol [g/L]	in aq. Phase [ng/L]		Single	Mean	SD ±	CV
1	70.76	23.220	120	193145018	8.286	8.224	0.062	0.76
	76.28	23.879	148	161092672	8.207
	118.74	24.217	145	166741900	8.222
	123.86	27.241	145	188101086	8.274
	142.69	24.651	291 (#1)	(84789176)	(7.928)
	147.69	24.169	179	134691288	8.129
2	70.76	23.426	158	148066436	8.170	8.221	0.058	0.70
	76.28	25.112	140	179371586	8.254
	118.74	27.090	134	201965041	8.305
	123.86	25.399	229 (#1)	(110964754)	(8.045)
	142.69	24.821	156	158903664	8.201
	147.69	23.392	157	149158977	8.174
3	70.76	22.265	272	81897537	7.913	8.005	0.057	0.71
	76.28	23.402	237	98648061	7.994
	118.74	27.708	228	121405921	8.084
	123.86	25.557	247	103363504	8.014
	142.69	23.372	240	97379337	7.988
	147.69	24.955	231	108214457	8.034
				Log Pow mean		8.150
				log POW,Av		8.146
				slog POW,Av		0.249

aq. Phase = Aqueous phase

POW = Partition coefficient (n-octanol / water)

Log POW = Decadic logarithm of the partition coefficient (n-octanol / water)

SD = Standard deviation

CV = Coefficient of variation [%]

log POW,Av = Weighted average value of log POW

slog POW,Av = Weighted standard deviation

(#1) : Determined to be an outlier via Grubbs-Test ; not taken into account in subsequent partition coefficient value determination (values bracketed to indicate exclusion)

Conclusions:

The octanol / water partition coefficient was determined to be log Pow = 8.146 ± 0.249 at 25 ± 1 °C and pH ca. 5.8.

Executive summary:

The partition coefficient of the substance was determined according to OECD TG 123 : slow stirring method under GLP, at 25 ± 1 °C from three independent replicates (test vessels) with four sub-replicates (samples). The pH-value of the aqueous phases was determined by a pH-meter. The mean pH was in range of 5.819 (start) and 5.881 (end) during the study. Analytical evaluation was performed using GC-MS/MS on a capillary analytical column using the test item for external calibration. The analytical method was validated with satisfactory results regarding linearity, limit of quantification, accuracy, precision and specificity. The temperatures were kept constant at 25 ± 1 °C. The mean log Pow values in the equilibration time for each replicate fell within a range of ± 0.3 log and equilibrium was determined by the regression line of the log Pow value vs. sampling time. A slope not significantly different from zero of at least 4 points verified the attainment of equilibrium. The octanol / water partition coefficient was determined to be log Pow = 8.146 ± 0.249 at 25 ± 1 °C and pH ca. 5.8.

Description of key information

log Pow (slow stir) =8.146 ± 0.249 at 25 ± 1 °C and pH ca. 5.8, OECD TG 123, 2020

Key value for chemical safety assessment

Log Kow (Log Pow):

8.146

at the temperature of:

25 °C

Additional information

Key study : OECD TG 123, 2020 : The partition coefficient of the substance was determined according to OECD TG 123 : slow stirring method under GLP, at 25 ± 1 °C from three independent replicates (test vessels) with four sub-replicates (samples). The pH-value of the aqueous phases was determined by a pH-meter. The mean pH was in range of 5.819 (start) and 5.881 (end) during the study. Analytical evaluation was performed using GC-MS/MS on a capillary analytical column using the test item for external calibration. The analytical method was validated with satisfactory results regarding linearity, limit of quantification, accuracy, precision and specificity. The temperatures were kept constant at 25 ± 1 °C. The mean log Pow values in the equilibration time for each replicate fell within a range of ± 0.3 log and equilibrium was determined by the regression line of the log Pow value vs. sampling time. A slope not significantly different from zero of at least 4 points verified the attainment of equilibrium. The octanol / water partition coefficient was determined to be log Pow = 8.146 ± 0.249 at 25 ± 1 °C and pH ca. 5.8.