4,4'-thiodiethylene hydrogen -2-octadecenylsuccinate

Adsorption / desorption

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

adsorption / desorption: screening

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1st February 2016 - 1st April 2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 121 (Estimation of the Adsorption Coefficient (Koc) on Soil and on Sewage Sludge using High Performance Liquid Chromatography (HPLC))

GLP compliance:

yes

Type of method:

HPLC estimation method

Media:

soil/sewage sludge

Specific details on test material used for the study:

Appearance: Brown waxy solid
Batch Ref: E00268-011-113/E00350-276
Sample Retest Date: March 26, 2017
Purity: 100%

Radiolabelling:

no

Test temperature:

maintained at 40°C

Details on study design: HPLC method:

In this experiment, the interaction of the test substance containing polar and/or non polar functional groups with a dual composition (polar and non polar sites) HPLC stationary phase mimicked the interaction of the test substance with organic matter present in soil and sludge matrices. The HPLC method was applicable to the test substance since an appropriate detection system (e.g. absorbance) was available and the test substance did not react either with the eluent or the stationary phase. The test substance met the other applicability criteria specified in the study protocol for use of the HPLC estimation method.

Six calibration reference standards, consisting of six reference substances of known log KOC, were prepared in the respective mobile phase at a nominal concentration (range 10.0-200 mg/L) selected to provide desired ultraviolet (UV) detector response. Capacity factors were calculated for the reference standards using urea to estimate column dead time (i.e. the retention time of an unretained organic compound). The logarithms of the capacity factors were then plotted against published log KOC values for the reference standards to establish a linear regression equation.

A test solution of EXP1504385 the Substance was prepared in 55% methanol (MeOH): 45% reagent water (H2O) (v/v) at a nominal concentration of 100 mg/L. The calibration reference standard preparations were sequentially injected into an HPLC system followed by single injections of three separate aliquots of the test substance preparation. The calibration reference standards injection sequence was repeated following the test substance injections.

The standardized isocratic, reverse-phase operating conditions provided in the guidelines were modified slightly due to high degree of retention of component(s) of this test substance on the column. Isocratic conditions were maintained until the retention time of the longest- retaining reference standard (DDT) had passed. Then a gradient was employed, increasing the concentration of methanol in the mobile phase, to force the remaining test substance component(s) off of the column

Analytical monitoring:

yes

Details on test conditions:

TEST SYSTEM: Analytical Column: Poroshell 120 EC-CN Column
(100x 3.0mm, 2.7µm particle size)
Mobile Phase: Methanol: Reagent Water

Key result

Sample No.:

#1

Type:

log Koc

Value:

< 1.25 dimensionless

pH:

6

Temp.:

40 °C

Matrix:

Analytical Column: Poroshell 120 EC-CN Column

Key result

Sample No.:

#2

Type:

log Koc

Value:

1.03

pH:

6

Temp.:

40 °C

Matrix:

Analytical Column: Poroshell 120 EC-CN Column

Key result

Sample No.:

#3

Type:

log Koc

Value:

> 5.63 dimensionless

pH:

6

Temp.:

40 °C

Matrix:

Analytical Column: Poroshell 120 EC-CN Column

Details on results (HPLC method):

The Substance may be classified as a UVCB (Chemical Substances of Unknown or Variable Composition, Complex Reaction Products and Biological Materials). For such test materials, the various components would be expected to be characterized by Log KOC that
spanned the applicable range of the HPLC-estimation methodology (Log KOC from 0 – 6 according to the guidelines) as was reported here. It is noted that use of UV detection is limited to those components in UVCB materials with chromophoric functionality. A more universal detector such as refractive index (RI) would have likely provided a different set of responses across the same range of Log KOC. However, the RI detector is far less sensitive, is not compatible with operation of an HPLC gradient and longer-chained components of the test material would not have been eluted from the column and detected as they were in the present study. In the opinion of the Study Director, the experimental design and conditions presented in this study were deemed to be most appropriate for the estimation of Log KOC for this test substance.

See attached background documents

Validity criteria fulfilled:

yes

Conclusions:

Under the chromatographic conditions specified, the Substance eluted as three discrete peaks, corresponding to mean estimated log Koc values of <1.25, 1.03 and >5.63.

Executive summary:

This study was performed to estimate the adsorption coefficient (KOC) of the Substance in soil and sludge using a high performance liquid chromatography (HPLC) based methodology. In the method, the retention times of test materials are correlated with those for reference standards of known adsorption coefficients. This study was based on procedures presented in the OECD Guideline for the Testing of Chemicals, Guideline121:Estimation of the Adsorption Coefficient (KOC) on Soil and on Sewage Sludge using High Performance Liquid Chromatography (HPLC) and Council of the European Communities, Method C.19,Estimation of the Adsorption Coefficient

(KOC) on Soil and on Sewage Sludge using High Performance Liquid Chromatography (HPLC).

The substance may be classified as a UVCB (Chemical Substances of Unknown or Variable Composition, Complex Reaction Products and Biological Materials). For such test materials, the various components would be expected to be characterized by Log KOC that spanned the applicable range of the HPLC-estimation methodology (Log KOC from 0 – 6 according to the guidelines) as was reported here. It is noted that use of UV detection is limited to those components in UVCB materials with chromophoric functionality. A more universal detector such as refractive index (RI) would have likely provided a different set of responses across the same range of Log KOC. However, the RI detector is far less sensitive, is not compatible with operation of an HPLC gradient and longer-chained components of the test material would not have been eluted from the column and detected as they were in the present study. In the opinion of the Study Director, the experimental design and conditions presented in this study were deemed to be most appropriate for the estimation of Log KOC for this test substance.

 

Under the chromatographic conditions specified, the Substance eluted as three discrete peaks. The mean log K_OCfor each of the peaks is presented in the following table:

 

Peak Number	Mean Log KOC
1	<1.25
2	1.03 ± 0.014
3	>5.63

Reference 2

Endpoint:

adsorption / desorption: screening

Type of information:

(Q)SAR

Adequacy of study:

weight of evidence

Study period:

25th November 2016

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

results derived from a valid (Q)SAR model, but not (completely) falling into its applicability domain, with adequate and reliable documentation / justification

Justification for type of information:

QSAR prediction

Guideline:

other: REACH guidance on QSARs R.6.

Principles of method if other than guideline:

Koc was estimated (executed by log Koc - EpiSuite in QSAR Toolbox 3.4.0.17) using the representative structure of the Substance.

GLP compliance:

no

Remarks:

Not applicable to QSAR models

Type of method:

other: calculation

Key result

Sample No.:

#1

Type:

Koc

Value:

2 640 000 000 L/kg

Temp.:

25 °C

Remarks on result:

other: QSAR

Key result

Sample No.:

#1

Type:

log Koc

Value:

9.42 L/kg

Temp.:

25 °C

Remarks on result:

other: QSAR

This was executed using Koc, Log Kow functions of EpiSuite 4.10 modelling in the QSAR Toolbox 3.4.0.17. The estimated the Log Koc for the representative Substance was 9.42 (Koc = 2.64E+9 L/kg).

Conclusions:

This was executed using Koc, Log Kow functions of EpiSuite 4.10 modelling in the QSAR Toolbox 3.4.0.17. The estimated the Log Koc for the representative Substance was 9.42 (Koc = 2.64E+9 L/kg).

Executive summary:

Initial attempts were made to experimentally determine the Partition Coefficient (Kow) for registration of the SubstanceThe substance may be classified as a UVCB (Chemical Substances of Unknown or Variable Composition, Complex Reaction Products and Biological Materials). For such test materials, the various components would be expected to be characterized by Log KOC that spanned the applicable range of the HPLC-estimation methodology (Log KOC from 0 – 6 according to the guidelines) as was reported here. It is noted that use of UV detection is limited to those components in UVCB materials with chromophoric functionality. A more universal detector such as refractive index (RI) would have likely provided a different set of responses across the same range of Log KOC. However, the RI detector is far less sensitive, is not compatible with operation of an HPLC gradient and longer-chained components of the test material would not have been eluted from the column and detected as they were in the present study. In the opinion of the Study Director, the experimental design and conditions presented in this study were deemed to be most appropriate for the estimation of Log KOC for this test substance.

The complex nature and physical properties of the substance made it difficult to provide a suitable log Koc value. Consequently, QSAR models was used to provide clarity and reflect the representative chemistry of the Substance. This was executed using Koc, Log Kow functions of EpiSuite 4.10 modelling in the QSAR Toolbox 3.4.0.17. The estimated the Log Koc for the representative Substance was 9.42 (Koc = 2.64E+9 L/kg).

Reference 3

Endpoint:

adsorption / desorption: screening

Type of information:

(Q)SAR

Adequacy of study:

key study

Study period:

25th November 2016

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

QSAR prediction

Guideline:

other: REACH guidance on QSAR R.6.

Principles of method if other than guideline:

Koc was estimated (executed by log Koc - EpiSuite in QSAR Toolbox 3.4.0.17) using the representative structure of the Substance.

GLP compliance:

no

Type of method:

other: QSAR

Key result

Sample No.:

#1

Type:

Koc

Value:

10 000 000 000 L/kg

Remarks on result:

other: QSAR Prediction

Key result

Sample No.:

#1

Type:

log Koc

Value:

10 dimensionless

Remarks on result:

other: QSAR

This was executed using Koc, MCI functions of EpiSuite 4.10 modelling in the QSAR Toolbox 3.4.0.17. The estimated the Log Koc for the representative Substance was 10 (Koc = 1.00E+10 L/kg).

Conclusions:

This was executed using Koc, MCI functions of EpiSuite 4.10 modelling in the QSAR Toolbox 3.4.0.17. The estimated the Log Koc for the representative Substance was 10 (Koc = 1.00E+10 L/kg).

Executive summary:

Initial attempts were made to experimentally determine the Partition Coefficient (Kow) for registration of the Substance. The substance may be classified as a UVCB (Chemical Substances of Unknown or Variable Composition, Complex Reaction Products and Biological Materials). For such test materials, the various components would be expected to be characterized by Log KOC that spanned the applicable range of the HPLC-estimation methodology (Log KOC from 0 – 6 according to the guidelines) as was reported here. It is noted that use of UV detection is limited to those components in UVCB materials with chromophoric functionality. A more universal detector such as refractive index (RI) would have likely provided a different set of responses across the same range of Log KOC. However, the RI detector is far less sensitive, is not compatible with operation of an HPLC gradient and longer-chained components of the test material would not have been eluted from the column and detected as they were in the present study. In the opinion of the Study Director, the experimental design and conditions presented in this study were deemed to be most appropriate for the estimation of Log KOC for this test substance.

The complex nature and physical properties of the substance made it difficult to provide a suitable log Koc value. Consequently, a QSAR model was used to provide clarity and reflect the representative chemistry of the Substance. This was executed using Koc, MCI functions of EpiSuite 4.10 modelling in the QSAR Toolbox 3.4.0.17. The estimated the Log Koc for the representative Substance was 10 (Koc = 1.00E+10 L/kg).

Description of key information

One study was conducted and estimated that the Substance will have Partition coefficient greater than the highest reference material (DDT, log Koc = 5.63). Based on the complexity of the Substance the Koc values have also been estimated from EpiSuite 4.10 (MCI and log Kow) QSAR models in the QSAR Toolbox 3.4.0.17. Koc estimated values for Substance using these models are 2.64E9 to 1.00E10 (Log Koc 9.42 to 10, respectively).  The major component is considered to have no significant UV-Vis absorbing functionality therefore the QSAR estimates of the Kow for the Substance was used.

For the purposes of the chemical safety assessment the lowest estimated LogKoc of 9.42 has been selected.

Key value for chemical safety assessment

Koc at 20 °C:

2 400 000 000

Additional information

Initial attempts were made to experimentally determine the Partition Coefficient (Kow) for registration of the SubstanceThe substance may be classified as a UVCB (Chemical Substances of Unknown or Variable Composition, Complex Reaction Products and Biological Materials). For such test materials, the various components would be expected to be characterized by Log KOC that spanned the applicable range of the HPLC-estimation methodology (Log KOC from 0 – 6 according to the guidelines) as was reported here. It is noted that use of UV detection is limited to those components in UVCB materials with chromophoric functionality. A more universal detector such as refractive index (RI) would have likely provided a different set of responses across the same range of Log KOC. However, the RI detector is far less sensitive, is not compatible with operation of an HPLC gradient and longer-chained components of the test material would not have been eluted from the column and detected as they were in the present study. In the opinion of the Study Director, the experimental design and conditions presented in this study were deemed to be most appropriate for the estimation of Log KOC for this test substance.

For the purposes of the chemical safety assessment the lowest estimated LogKoc of 9.42 was selected.

[LogKoc: 9.42]