Hydrocarbons, C10-C13, n-alkanes, isoalkanes,

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: 03 December 2013; Experimental Completion Date: 10 March 2014

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

Study conducted in compliance with agreed protocols, with no or minor deviations from standard test guidelines and/or minor methodological deficiencies, which do not affect the quality of the relevant results. The study report was conclusive, done to a valid guideline and the study was conducted under GLP conditions.

Qualifier:

according to guideline

Guideline:

EU Method A.8 (Partition Coefficient)

Deviations:

no

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes

Type of method:

HPLC method

Partition coefficient type:

octanol-water

Analytical method:

high-performance liquid chromatography

Key result

Type:

log Pow

Partition coefficient:

>= 5.57 - <= 6.62

Temp.:

35 °C

pH:

7.33

Results

Preliminary estimate

Approximate solubility in n-octanol: greater than 1.00 x 10⁵ mg/L

Approximate solubility in water:       less than 10.6 mg/L

Approximate partition coefficient:    greater than 9.47 x 10³(log P_ow> 3.98)

Definitive test

Please see Attachment 2 for the Typical Chromatography.

Calibration

 

The dead time and the retention times, capacity factors (k′) and log₁₀P_ow values for the reference standards are shown in the following tables:

Table 3.10

 

Dead Time	Retention Time (min)		Mean Retention Time (min)
	Injection 1	Injection 2
Formamide	1.686	1.688	1.687

 

Table 3.11

 

Standard	Retention Time (min)		Mean Retention Time (min)	Capacity Factor (k′)	log10k′	log10Pow
	Injection 1	Injection 2
Hexane	4.655	4.652	4.654	1.76	0.245	3.90
Heptane	5.324	5.320	5.322	2.15	0.333	4.66
Octane	6.129	6.128	6.129	2.63	0.420	5.18
Nonane	7.124	7.121	7.123	3.22	0.508	5.65
Dodecane	11.575	11.568	11.572	5.86	0.768	6.10
Tetradecane	16.319	16.319	16.319	8.67	0.938	7.20

Partition coefficient of sample

 

The retention times, capacity factors and log₁₀P_ow values determined for the sample are shown in the following table:

 

Table 3.12

 

Peak	Injection	Retention Time (mins)	Capacity Factor (k′)	log10k′	log10Pow	Mean log10Pow	Pow	Mean Area%
1	1	7.842	3.65	0.562	5.57	5.57	3.69 x 10^5	2.25
	2	7.843	3.65	0.562	5.57
2	1	8.322	3.93	0.595	5.71	5.71	5.15 x 10^5	9.41
	2	8.324	3.93	0.595	5.71
3	1	9.040	4.36	0.639	5.91	5.91	8.10 x 10^5	16.8
	2	9.032	4.35	0.639	5.91
4	1	9.779	4.80	0.681	6.09	6.09	1.24 x 10^6	25.1
	2	9.779	4.80	0.681	6.09
5	1	10.521	5.24	0.719	6.26	6.27	1.85 x 10^6	25.4
	2	10.548	5.25	0.720	6.27
6	1	11.535	5.84	0.766	6.47	6.47	2.98 x 10^6	15.7
	2	11.537	5.84	0.766	6.47
7	1	12.289	6.28	0.798	6.62	6.62	4.1 x 10^6	5.28
	2	12.297	6.29	0.799	6.62

 

Overall log₁₀P_ow:      5.57 to 6.62

Partition coefficient:  3.69 x 10⁵ to 4.13 x 10⁶  

Conclusions:

Please see the Executive Summary for the Conclusion.

Executive summary:

The determination was carried out using the HPLC Method designed to be compatible with Method A8 Partition Coefficient of Commission Regulation (EC) No 440/2008 of 30 May 2008 and Method 117 of the OECD Guidelines for Testing of Chemicals, 13 April 2004.

 

The test system consisted of a high performance liquid chromatograph with a suitable detector. A reverse phase HPLC column with a very low percentage of polar groups was used (e.g. C8, C18). The mobile phase contained at least 25% aqueous phase.

 

Conclusion

The partition coefficient of the test item has been determined to be in the range 3.69 x 10⁵ to 4.13 x 10⁶ (log₁₀ P_ow 5.57 to 6.62).

Description of key information

Log Kow (constituents of the substance): ≥5.57 to ≤6.62 at 35°C and pH 7.3 (measured)

Log Kow (constituents): 5.11 - 7.22 at 20°C (QSAR)

Additional information

The substance is a hydrocarbon UVCB. Standard tests for this endpoint are intended for single substances and are not appropriate for this complex substance. However, this endpoint is characterised using quantitative structure property relationships for representative hydrocarbon structures that comprise the hydrocarbon blocks used to assess the environmental risk of this substance with QSAR software (see IUCLID Section 13).

The log K_ow of the constituents of the substance have been determined using the HPLC method in accordance with OECD 117 Test Method and in compliance with GLP. The partition coefficient of the substance was determined to be in the range ≥3.69 x 10⁵ to ≤4.13 x 10⁶ (log₁₀ P_ow  ≥5.57 to ≤6.62) at 35°C and pH 7.3. The result was considered to be reliable but the results are not useful for chemical safety assessment.

As supporting information, the log K_ow for individual constituents of Hydrocarbons, C10-C13, n-alkanes, isoalkanes, <2% aromatics have been predicted using a validated QSAR estimation method. The prediction method uses a fragment method and log K_ow increases with increasing carbon number. The individual constituents of the substance have predicted log K_ow values in the range 5.11 - 7.22 at 20°C.