Oligomerisation products of alpha-pinene and beta-pinene

Partition coefficient

Link to relevant study record(s)

Reference

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Study period:

22 February 2018 - 26 February 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other:

Remarks:

Study conducted according to A8 method and OECD guideline 117, under GLP without deviation and with certificate of analysis included.

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to other 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)

Version / remarks:

(13 April 2004)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

2017-01-10

Type of method:

HPLC method

Partition coefficient type:

octanol-water

Analytical method:

high-performance liquid chromatography

Key result

Type:

log Pow

Partition coefficient:

> 7.41 - < 8.02

Temp.:

30 °C

pH:

ca. 6.5

Remarks on result:

other: These values are the mean of three independent measurements.

Reference items:

Retention times and capacity factors

The retention times of the reference items are presented in the following table.

Compound	tR1 (min)	tR2 (min)	delta tR (min)	Mean (min)	delta tR / Mean	Equilibrium ?
benz[a]anthracene	4.27	4.25	0.02	4.26	0.47%	YES
heptachlor	4.25	4.32	0.07	4.29	1.63%	YES
PCB 50	4.21	4.15	0.06	4.18	1.44%	YES
benzo[a]pyrene	5.79	5.76	0.03	5.78	0.52%	YES
dibenz[a,c]anthracene	7.05	7.00	0.05	7.03	0.71%	YES
PCB 103	5.93	5.83	0.10	5.88	1.70%	YES
cypermethrin	n.d.
benzo[b]perylene	9.15	9.09	0.06	9.12	0.66%	YES
bifenthrin	6.55	6.69	0.14	6.62	2.11%	NO
PCB 169	12.42	12.25	0.17	12.34	1.38%	YES
PCB 194	18.83	18.78	0.05	18.81	0.27%	YES
PCB 198	16.88	16.79	0.09	16.84	0.53%	YES
PCB 209	40.71	41.07	0.36	40.89	0.88%	YES

n.d.: not determined

t_R: retention time

delta t_R: absolute value of the retention times difference

Two reference substances were discarded from the calibration curve:

- the first one is cypermethrin because it eluted in two peaks, whereas only one log Pow is given for all isomers

- the second one is bifenthrin because its difference in the retention time values between the two analyses was above the equilibrium criteria (2.11% for 2%). this behaviour seemed to be compound dependent since it was the only one reference compound with a variation above 2%.

Dead times (t₀) for these injections (determined at 208 nm) are listed in the following table:

MIX HPA  MIX PCB  MIX 3  First injection: t0 (min)  0.99  1.02  1.00  Second injection: t0 (min)  0.99  1.02  1.01

The equilibrium state of the system is declared valid since the difference of the reference items retention times (delta t_R / Mean) did not exceed 2%, except for bifenthrin.

Log Pow/log k

The following table presents for each reference item their log Pow, the calculated retention factor for the two injections (k1 and k2), the mean of k1 and k2 (k mean), and log (k mean):

Compound  log Pow  k1  k2  k mean  log (k mean)  benz[a]anthracene  5.76 3.31  3.29  3.30  0.52   heptachlor  6.10 3.25  3.28  3.26  0.51   PCB 50  6.34 3.13  3.07  3.10  0.49   benzo[a]pyrene  6.35 4.85  4.82  4.83  0.68   dibenz[a,c]anthracene  6.41 6.12  6.07  6.10  0.79   PCB 103  6.44 4.81  4.72  4.76  0.68   benzo[b]perylene  7.03 8.24  8.18  8.21  0.91   PCB 169  7.41 11.18  11.01  11.09  1.05   PCB 194  7.67 17.46  17.41  17.44  1.24   PCB 198  7.80  15.55 15.46  15.50  1.19   PCB 209  8.27 38.91  39.26  39.09  1.59

The logarithms of the mean capacity factors, log k, were plotted as a function of log Pow. The linear regression obtained with the reference items is presented in the following graph (illustration) with the representation of the confidence interval (in orange) calculated with a 98% confidence level.

The determination coefficient R² observed is 0.9382 and the correlation coefficient R is 0.9686. According to the guideline, a typical correlation coefficient for the relationship between log k and log Pow for a set of test substances is around 0.9. therefore, the obtained coefficients were quite satisfactory.

The equation of the line issued from the linear regression was used for the test item log Pow calculation.

Test item:

Retention times and capacity factors:

The retention times obtained are presented in the following table:

Injection 1 tR (min)  Injection 2 tR (min)  Injection 3 tR (min)  Mean (min) Relative standard deviation   Dead time  0.95 0.95  0.95  0.95  0.0%   First set (dimers) start  13.00 13.12   13.08 13.07  0.5%   First set (dimers) end  23.06 22.93  22.98  22.99  0.3%

Calculation of k, log k and log Pow

The calculated values for the test item are presented in the following table. log Pow is calculated using the regression equation obtained from the reference items: log Pow = (log k +2.0476) / 0.4257

First set (dimers) start        First set (dimers) end  Measurement No.  k  log k  log Pow  k  log k  log Pow  1  12.68 1.10  7.40  23.27  1.37  8.02   2  12.81 1.11  7.41  23.14  1.36  8.01   3  12.77 1.11  7.41  23.19  1.37  8.02         Mean  7.41             8.02        Standard deviation  0.006  0.01

Conclusions:

Using the HPLC method, the following partition coefficients were determined for the test item:
Dimers (representing 79.2% of the test item): log Pow between 7.41 and 8.02.
These values are the mean of three independent measurements.

Executive summary:

Determination of the Partition Coefficient n-octanol/water (log Pow) of TERPENIC OLIGOMERS.

A study was performed to assess the partition coefficient of the test item by the HPL method. The method followed was designed to be compliant with the OECD Guideline for Testing of Chemicals No. 117, ''Partition Coefficient (n-octanol/water): HPLC Method''.

This study was performed using the HPLC method. Eleven reference items with different retention times were used to produce the calibration curve. They were chosen in relation with the expected retention time of the test item. For each reference item, two determinations were performed. The capacity factor k was calculated from the retention time of acetone (dead time) and the retention time of the respective reference item. A calibration function (log k versus log Pow, linear fit) was determined based on literature values of Pow for the reference items.

The following partition coefficient range was determined for the dimers of the test item (representing 79.2% of the test item) between 7.41 and 8.02.

These values are the mean of three independent measurements.

Description of key information

Using the HPLC method, the following partition coefficients were determined for the test item:

Dimers (representing 79.2% of the test item): log Pow between 7.41 and 8.02.

These values are the mean of three independent measurements.  

Key value for chemical safety assessment

Log Kow (Log Pow):

8

at the temperature of:

25 °C

Additional information

The partition coefficient of the test substance was measured under GLP according to Guideline OECD 117/EU A8, HPLC method. The system was calibrated with 13 reference substances, and the result for the sample was interpolated from the linear regression.