Hydrocarbons, C15-C19, 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: 05 December 2013 Experimental Completion Date: 11 March 2014

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

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:

> 7.2

Temp.:

35 °C

pH:

7.33

Remarks on result:

other: Log Kow of >7.20 was determined for constituents of the substance

Results

Preliminary estimate

Approximate solubility in n-octanol: greater than 9.99 x 10⁴ mg/L

Approximate solubility in water:       less than 11.4 mg/L

Approximate partition coefficient:    greater than 8.76 x 10³ (log P_ow > 3.94)

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	1.680	1.680	1.680

 

Table 3.11

 

Standard	Retention Time (min)		Mean Retention Time (min)	Capacity Factor (k′)	log10k′	log10Pow
	Injection 1	Injection 2
Hexane	4.646	4.645	4.646	1.77	0.247	3.90
Heptane	5.314	5.313	5.314	2.16	0.335	4.66
Octane	6.122	6.119	6.121	2.64	0.422	5.18
Nonane	7.114	7.110	7.112	3.23	0.510	5.65
Dodecane	11.559	11.546	11.553	5.88	0.769	6.10
Tetradecane	16.293	16.279	16.286	8.69	0.939	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	16.197	8.64	0.937	> 7.20	> 7.20	> 1.58 x 10^7	3.03
	2	16.194	8.64	0.936	> 7.20
2	1	17.795	9.59	0.982	> 7.20	> 7.20	> 1.58 x 10^7	6.36
	2	18.059	9.75	0.989	> 7.20
3	1	19.304	10.49	1.021	> 7.20	> 7.20	> 1.58 x 10^7	9.25
	2	19.318	10.50	1.021	> 7.20
4	1	20.671	11.30	1.053	> 7.20	> 7.20	> 1.58 x 10^7	15.9
	2	20.696	11.32	1.054	> 7.20
5	1	23.038	12.71	1.104	> 7.20	> 7.20	> 1.58 x 10^7	15.7
	2	23.050	12.72	1.104	> 7.20
6	1	24.655	13.68	1.136	> 7.20	> 7.20	> 1.58 x 10^7	16.8
	2	24.647	13.67	1.136	> 7.20
7	1	27.451	15.34	1.186	> 7.20	> 7.20	> 1.58 x 10^7	13.5
	2	27.428	15.33	1.185	> 7.20
8	1	29.318	16.45	1.216	> 7.20	> 7.20	> 1.58 x 10^7	14.3
	2	29.406	16.50	1.218	> 7.20
9	1	32.619	18.42	1.265	> 7.20	> 7.20	> 1.58 x 10^7	3.08
	2	32.883	18.57	1.269	> 7.20
10	1	35.026	19.85	1.298	> 7.20	> 7.20	> 1.58 x 10^7	2.16
	2	35.469	20.11	1.303	> 7.20

 

Overall log₁₀P_ow:        > 7.20

Partition coefficient:  greater than 1.58 x 10⁷

 

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 greater than 1.58 x 10⁷(log₁₀ P_ow > 7.20).

Description of key information

Log K_ow (constituents of the substance): >7.2 at 35°C and pH 7.3 (measured).

Log K_ow (constituents): 6.58 - >9.0 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 Section 13).

The log K_ow of the constituents of the substance have been measured using the HPLC method in accordance with OECD 117 Test Method and in compliance with GLP. The n-octanol/water partition coefficients of the constituents were determined to be >1.58 x 107 (log10 P_ow >7.2) at 35°C and pH 7.3. The study was considered to be reliable but the results are not useful for chemical safety assessment.

As supporting information, log K_ow values for individual constituents of Hydrocarbons, C15-C19, n-alkanes, isoalkanes, <2% aromatics have been predicted using a separately validated QSAR estimation method. The prediction method uses a fragment method and log K_ow increases with increasing carbon number. The prediction domain covers carbon chain length in the range C1-C18 carbon atom, it is therefore expected that log K_ow for longer chain length (i.e. greater than C18) compounds will be greater than the predicted value of 9.18 for C18 atom. The individual constituents of the substance have predicted log K_ow values in the range 6.58 - >9 at 20°C.