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EC number: 429-900-5 | CAS number: 82356-51-2
Partition coefficient
Administrative data
Link to relevant study record(s)
- Endpoint:
- partition coefficient
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Study period:
- 2012-11-22 to 2013-01-28
- Reliability:
- 1 (reliable without restriction)
- Rationale for reliability incl. deficiencies:
- guideline study
- Remarks:
- The study was conducted according to an internationally recognised method, and under GLP. No deviation affected the quality of the study. The test substance composition is adequately characterised with its purity. Therefore full validation applies.
- Qualifier:
- according to guideline
- Guideline:
- OECD Guideline 123 (Partition Coefficient (1-Octanol / Water), Slow-Stirring Method)
- Version / remarks:
- (March 23, 2006)
- GLP compliance:
- yes (incl. QA statement)
- Remarks:
- Inspected on 14 September 2010. Signed on 07 February 2011
- Type of method:
- slow-stirring method
- Partition coefficient type:
- octanol-water
- Analytical method:
- liquid chromatography
- Type:
- log Pow
- Partition coefficient:
- 5.522
- Temp.:
- 25 °C
- pH:
- >= 6 - <= 8.3
- Conclusions:
- The substance has potential to bioaccumulate in the environment, according to CLP classification criteria for aquatic chronic toxicity (log Kow >4).
- Executive summary:
The partition coefficient (log Kow) of the test substance was measured under GLP according OECD 123 guideline, slow-stirring method.
A preliminary assay was conducted with a single vessel, to determine the equilibration time, which was reached from 24 hours. In the main test, three vessels were prepared, and five samples were taken in each phase after equilibration at 25°C, between 66 and 116 hours. The concentrations were measured in each phase with LC-MS/MS fully validated analysis method.
The overall average log Kow was calculated, weighted for the variance, to 5.52.
- Endpoint:
- partition coefficient
- Type of information:
- read-across from supporting substance (structural analogue or surrogate)
- Adequacy of study:
- key study
- Justification for type of information:
- Based on structural similarity (the source substance is one of the constituents of the target substance, together with isomers), both substances are not expected to have significantly different partition coefficient. Therefore the result of the study is considered suitable for the target substance.
Further information is included in IUCLID Section 13. - Reason / purpose for cross-reference:
- read-across source
- Key result
- Type:
- log Pow
- Partition coefficient:
- 5.522
- Temp.:
- 25 °C
- pH:
- >= 6 - <= 8.2
- Conclusions:
- (from analogue) The substance has potential to bioaccumulate in the environment, according to CLP classification criteria for aquatic chronic toxicity (log Kow >4).
- Executive summary:
The partition coefficient (log Kow) of the analogue test substance was measured under GLP according OECD 123 guideline, slow-stirring method.
A preliminary assay was conducted with a single vessel, to determine the equilibration time, which was reached from 24 hours. In the main test, three vessels were prepared, and five samples were taken in each phase after equilibration at 25°C, between 66 and 116 hours. The concentrations were measured in each phase with LC-MS/MS fully validated analysis method.
The overall average log Kow was calculated, weighted for the variance, to 5.52.
A similar logKow is anticipated for the target substance.
- Endpoint:
- partition coefficient
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Study period:
- 12-2006
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- guideline study without detailed documentation
- Remarks:
- The study was conducted according to an internationally recognised method. Purity and isomers composition are available from the notifier. However, some informations are missing in the report. Therefore validation applies, but with restrictions.
- Qualifier:
- according to guideline
- Guideline:
- EU Method A.8 (Partition Coefficient)
- Deviations:
- yes
- Remarks:
- log Kow value for reference substance DDT
- GLP compliance:
- no
- Type of method:
- HPLC method
- Partition coefficient type:
- octanol-water
- Analytical method:
- high-performance liquid chromatography
- Type:
- log Pow
- Partition coefficient:
- 6.39
- Temp.:
- 30 °C
- Remarks on result:
- other: pH is not specified
- Type:
- log Pow
- Partition coefficient:
- 6.23
- Remarks on result:
- other: recalculated for DDT reference value
- Conclusions:
- The substance has potential to bioaccumulate in the environment, according to CLP classification criteria for aquatic chronic toxicity (log Kow >4).
- Executive summary:
The partition coefficient of the test substance was measured according to the EU A8 guideline, HPLC method.
The system was calibrated with 6 reference substances, and the result for the sample was interpolated from the linear regression.
The partition coefficient (logKow) of the test substance was determined to be 6.23.
- Endpoint:
- partition coefficient
- Type of information:
- experimental study
- Adequacy of study:
- supporting study
- Study period:
- 1994-09-05 to 1994-09-07
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- guideline study with acceptable restrictions
- Remarks:
- The study was conducted according to an internationally recognised method, and under GLP. However, the flask method is not considered suitable for substances with log Kow > 4, and concentrations were determined versus a single calibration point. Moreover, purity is specified, but no certificate of analysis is provided (i.e. isomers composition and impurities not stated). Therefore, validation applies, but with restrictions.
- Qualifier:
- according to guideline
- Guideline:
- EU Method A.8 (Partition Coefficient)
- GLP compliance:
- yes (incl. QA statement)
- Remarks:
- Inspected on 31 January 1994. Signed on 16 March 1994
- Type of method:
- shake-flask method to: flask method
- Partition coefficient type:
- octanol-water
- Analytical method:
- gas chromatography
- Type:
- log Pow
- Partition coefficient:
- > 4.88
- Temp.:
- 22.5 °C
- pH:
- 6.6
- Conclusions:
- The substance has potential to bioaccumulate in the environment, according to CLP classification criteria for aquatic chronic toxicity (log Kow >4).
- Executive summary:
The partition coefficient of the test substance was measured, under GLP, according to the EU A8 guideline, flask method.
Three ratio were prepared in duplicate, each phase was analysed by GC, and the mean result from the 6 samples was retained. As no test substance was detected in the aqueous phase, the result is expressed as a limit value.
The partition coefficient of the test substance was determined to be > 4.88.
Referenceopen allclose all
Equilibrium test
| Equilibration time (h) | log Pow |
| 24.00 | 5.597 |
| 29.50 | 5.568 |
| 46.17 | 5.560 |
| 52.25 | 5.543 |
| 70.00 | 5.552 |
The mean log Pow determined during the equilibrium test was 5.564 with a RSD of 0.37%. The slope was not significantly different from 0, indicating that equilibrium was already reached after 24 hours.
Main tests
| Measured log Pow | |||
| Sampling time (h) | Vessel 1 | Vessel 2 | Vessel 3 |
| 66.58 | 5.525 | 5.509 | 5.510 |
| 73.25 | 5.550 | 5.522 | 5.513 |
| 90.50 | 5.560 | 5.521 | 5.545 |
| 96.58 | 5.543 | 5.530 | 5.515 |
| 116.3 | 5.519 | 5.499 | 5.497 |
| Statistical values | |||
| Mean log Pow | 5.5393 | 5.5161 | 5.5159 |
| Variance | 0.00029 | 0.000153 | 0.000309 |
| SD | 0.0171 | 0.0124 | 0.0176 |
| RSD (%) | 0.31 | 0.22 | 0.32 |
The state of equilibrium was also checked.
The weighted average log Pow was calculated to be 5.522, with a weighted standard error of 0.019.
Standards
| RT | K | log K | log Pow | |
| T0 | 1.69 | 0 | - | - |
| isoprop | 3.74 | 1.22 | 0.085 | 3.70 |
| biph | 3.97 | 1.35 | 0.131 | 4.00 |
| n-but | 4.87 | 1.88 | 0.275 | 4.50 |
| 2,6-dip | 5.16 | 2.05 | 0.313 | 4.90 |
| triph | 6.89 | 3.08 | 0.489 | 5.70 |
| DDT | 7.54 | 3.47 | 0.540 | 6.50 |
Calibration
Log Pow = (log K x slope) + intercept
slope = 5.66
intercept = 3.1525
correlation = 0.9827
Sample
| Tr | K | log K | log Pow | |
| T0 | 1.69 | 0 | - | - |
| Test substance | 7.98 | 3.733 | 0.572 | 6.39 |
The preliminary test determined the partition coefficient to be greater than 1.02 x 104, Log10 Pow > 4.01.
The peak heights of the pair of standards associated with a particular sample were corrected to nominal concentration and the mean value taken prior to the calculation of the sample concentrations.
| Sample number | Volume of n-octanol (mL) | Volume of water (mL) | Total weight (mg) | n-octanol phase | Water phase | |||
| Analysed concentration (mg/L) | Total weight (mg) | Analysed concentration (mg/L) | Total weight (mg) | pH | ||||
| 1 | 5 | 200 | 5.27 | 1.04 x 103 | 5.20 | < 1.34 x 10-2 | < 2.67 x 10-3 | 6.6 |
| 2 | 5 | 200 | 5.27 | 1.05 x 103 | 5.26 | < 1.34 x 10-2 | < 2.67 x 10-3 | 6.5 |
| 3 | 10 | 200 | 10.5 | 1.03 x 103 | 10.3 | < 1.34 x 10-2 | < 2.67 x 10-3 | 6.6 |
| 4 | 10 | 200 | 10.5 | 1.03 x 103 | 10.3 | < 1.34 x 10-2 | < 2.67 x 10-3 | 6.6 |
| 5 | 20 | 200 | 21.1 | 1.02 x 103 | 20.4 | < 1.34 x 10-2 | < 2.67 x 10-3 | 6.6 |
| 6 | 20 | 200 | 21.1 | 1.06 x 103 | 21.3 | < 1.34 x 10-2 | < 2.67 x 10-3 | 6.7 |
Temperature = 22.5 +/-0.5°C
pH of n-octanol saturated water = 6.6
Calculations
| Sample number | n-octanol / water volume ratio | Partition coefficient | Log10 Pow |
| 1 | 1:40 | > 7.78 x 104 | > 4.89 |
| 2 | 1:40 | > 7.87 x 104 | > 4.90 |
| 3 | 1:20 | > 7.71 x 104 | > 4.89 |
| 4 | 1:20 | > 7.72 x 104 | > 4.89 |
| 5 | 1:10 | > 7.66 x 104 | > 4.88 |
| 6 | 1:10 | > 7.97 x 104 | > 4.90 |
Pow > 7.66 x 104, Log10 Pow > 4.88
Description of key information
(from analogue) Potential for bioaccumulation, according to CLP classification criteria for aquatic chronic toxicity (log Kow >4).
Key value for chemical safety assessment
- Log Kow (Log Pow):
- 5.52
- at the temperature of:
- 25 °C
Additional information
Three reliable studies, conducted according to recognized OECD/EC methods are available:
- The oldest (Safepharm 1994) was performed with the flask method, but provides only a limit value, sufficient for classification purpose, but not for ERA, and was therefore considered as supporting;
- (Firmenich 2006) was performed with the HPLC method, based on comparative elution versus standards; isomers were not differentiated;
- (Fraunhofer 2013) was not performed on the parent substance, but on an analogue, i.e. single isomer of the present multiconstituent, so the read-across was considered justified, in particular as isomers were not differentiated in the previous study. This study was conducted, under GLP, with the slow-stirring method, which is considered more accurate as based on actual phase partitioning and analysis (see IUCLID section 13 for justification).
Therefore the slow-stirring result is preferred and retained as key data, rather than the mean value.
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