Amidation products of C16-18 (even numbered), C18 unsaturated fatty acids esters with 1,1'-iminodipropan-2-ol

Adsorption / desorption

Link to relevant study record(s)

Reference

Endpoint:

adsorption / desorption: screening

Type of information:

experimental study

Adequacy of study:

key study

Study period:

06 September 2016 to 19 May 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

EU Method C.19 (Estimation of the Adsorption Coefficient (KOC) on Soil and Sewage Sludge Using High Performance Liquid Chromatography (HPLC))

Version / remarks:

European Community (EC), EC no. 440/2008, Part C: Methods for the Determination of Ecotoxicity, Guideline C.19: “Estimation of the Adsorption Coefficient (Koc) on Soil and on Sewage Sludge using High Performance Liquid Chromatography (HPLC)”, Official Journal of the European Union no. L142, May 31, 2008.

Deviations:

no

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))

Version / remarks:

Organization for Economic Co-operation and Development (OECD), OECD Guideline for the Testing of Chemicals no. 121: "Estimation of the Adsorption Coefficient (Koc) on Soil and on Sewage Sludge using High Performance Liquid Chromatography (HPLC)”, January 22, 2001.

Deviations:

no

GLP compliance:

yes

Type of method:

HPLC estimation method

Media:

soil

Specific details on test material used for the study:

No further details specified in the study report.

Radiolabelling:

no

Test temperature:

Column temperature 35°C ± 1°C

Details on study design: HPLC method:

Performance of the study
The principle of the test method is similar to that of the OECD guideline no. 117: "Partition coefficient (n-octanol/water), high performance liquid chromatography (HPLC) method". While passing through the column along with the mobile phase the test item interacts with the stationary phase. As a result of partitioning between mobile and stationary phases, the test item is retarded. The dual composition of a cyanopropyl stationary phase, having polar and non-polar sites allows for interaction of polar and non-polar groups of a molecule in a similar way as is the case for organic matter in soil or sewage sludge matrices. This enables the relationship between the retention time on the column and the Koc on organic matter to be established.
The test item is a UVCB. In order to determine whether the N,N-bis(2-hydroxypropyl) tallow amide compounds in the test item are ionised for 10% or more in the pH range 5.5-7.5, the pKa values of the C16:0 and C18:1 compounds were calculated using the Perrin calculation method (pKalc 5.0, module in Pallas 3.0, CompuDrug International San Francisco, CA, USA). The calculations showed that the N,N-bis(2-hydroxypropyl) tallow amide compounds in the test item do not have pKa values in the pH range 1-14 and that in this pH range they are in their non-ionised form. The HPLC analysis was therefore performed without buffering of the mobile phase (neutral pH).
Solutions of reference substances with known log Koc values based on soil adsorption data and the test item were analysed. The capacity factor (k') of each compound was calculated from its retention time. The log k’ values of the references substances were plotted against the known log Koc values. A linear regression program was used to calculate the calibration curve. Linear regression analysis was performed using the least squares method. The coefficient of correlation (r) was calculated. The log Koc value for the test item was calculated by substituting its mean log k’ in the calibration curve. The value of log Koc obtained from duplicate measurements was within ± 0.25 log units.

Analytical method
Analytical conditions
Instrument: Acquity UPLC system (Waters, Milford, MA, USA)
Detector: Acquity UPLC PDA detector (Waters)
Column Acquity UPLC HSS Cyano, 100 mm x 2.1 mm i.d., dp = 1.8 μm (Waters)
Column temperature: 35 °C ± 1 °C
Mobile phase:
A - methanol
B - water
Gradient:
Time %A %B
[minutes]
0 55 45
10 55 45
10.1 100 0
40 100 0
40.1 55 45
50 55 45
Flow: 0.4 mL/min
Injection volume: 1 μL
UV detection: 210 nm

Preparation of the solutions
Solution of the unretained compound
A 5.0 g/L stock solution of formamide (99.2%, [75-12-7], Alfa Aesar, Karlsruhe, Germany) in methanol was used. The stock solution was diluted to obtain an end solution of 55/45 (v/v) methanol/water. The formamide blank solution was 55/45 (v/v) methanol/water.
Reference substance solutions
Stock solutions of the reference substances at concentrations of approximately 1 g/L in methanol were used. The stock solutions were diluted to obtain an end solution of 55/45 (v/v) methanol/water. The blank solution for the mixture of reference substances was 55/45 (v/v) methanol/water.
Test solution
A 1000 mg/L solution of the test item was prepared in methanol. The test item blank solution was methanol.

Injections
The reference substance and test item solutions were injected in duplicate. Blank solutions were analysed by single injection.

Key result

Type:

Koc

Value:

> 250 000 - < 2 100 000 dimensionless

pH:

7

Key result

Type:

log Koc

Value:

> 5.4 - < 6.3 dimensionless

pH:

7

Details on results (HPLC method):

Determination of the Koc
In the chromatogram of the test solution, six major and several smaller test item peaks were observed. Peak area percentages were not calculated since compounds did not all elute in the isocratic part of the analysis.
The smaller peaks were observed at a retention time between 1.1 and 11.8 minutes.
The equation of the regression line was: log k’ = 0.315 x log Koc – 0.850 (r = 0.98, n = 16).

K_ocof the test item

Substance	tr,1 [min]	tr,2 [min]	Mean tr (n=2)	Log Koc	Koc
Formamide (t0)   Acetanilide Monuron 2,5-Dichloroaniline Naphthalene Benzoic acid phenylester Fenthion Phenanthrene 4,4’-DDT   Test item – peak 1 Test item – peak 2 Test item – peak 3 Test item – peak 4 Test item – peak 5 Test item – peak 6	0.667   0.869 1.056 1.194 1.376 1.606 2.100 2.327 5.529   5.387 7.014 8.288 9.866 11.684 11.970	0.673   0.869 1.057 1.201 1.385 1.613 2.121 2.347 5.611   5.405 7.046 8.333 9.923 11.685 11.970	0.670                     5.396 7.030 8.311 9.895 11.685 11.970	1.26 1.99 2.585 2.75 2.87 3.31 4.09 5.63   5.4 5.8^1 6.1^1 6.3^1 >6.3 >6.3	2.5 x 10^5 6.4 x 10^5 1.1 x 10^6 2.1 x 10^6 >2.1 x 10^6 >2.1 x 10^6

 

Validity criteria fulfilled:

yes

Conclusions:

The HPLC method using soil-adsorption-reference data was applied for the determination of the adsorption coefficient (Koc) of MLA-3202.
The Koc and log Koc values of the test item at neutral pH were:
Koc Log Koc
Test item – peak 1 2.5E+5 5.4
Test item – peak 2 6.4E+5 5.8
Test item – peak 3 1.1E+6 6.1
Test item – peak 4 2.1E+6 6.3
Test item – peak 5 >2.1E+6 >6.3
Test item – peak 6 >2.1E+6 >6.3

Executive summary:

The purpose of the study was to determine the following physico-chemical properties for MLA-3202:

Adsorption coefficient

 

The study was performed in accordance with the following guideline:

European Community (EC), EC no. 440/2008, Part C: Methods for the Determination of Ecotoxicity, Guideline C.19: “Estimation of the Adsorption Coefficient (Koc) on Soil and on Sewage Sludge using High Performance Liquid Chromatography (HPLC)”, Official Journal of the European Union no. L142, May 31, 2008.

Organization for Economic Co-operation and Development (OECD), OECD Guideline for the Testing of Chemicals no. 121: "Estimation of the Adsorption Coefficient (Koc) on Soil and on Sewage Sludge using High Performance Liquid Chromatography (HPLC)”, January 22, 2001.

 

The principle of the test method is similar to that of the OECD guideline no. 117: "Partition coefficient (n-octanol/water), high performance liquid chromatography (HPLC) method".

While passing through the column along with the mobile phase the test item interacts with the stationary phase. As a result of partitioning between mobile and stationary phases, the test item is retarded. The dual composition of a cyanopropyl stationary phase, having polar and non-polar sites allows for interaction of polar and non-polar groups of a molecule in a similar way as is the case for organic matter in soil or sewage sludge matrices. This enables the relationship between the retention time on the column and the Koc on organic matter to be established.

 

The test item is a UVCB. In order to determine whether the N,N-bis(2-hydroxypropyl) tallow amide compounds in the test item are ionised for 10% or more in the pH range 5.5-7.5, the pKa values of the C16:0 and C18:1 compounds were calculated using the Perrin calculation method (pKalc 5.0, module in Pallas 3.0, CompuDrug International San Francisco, CA, USA). The calculations showed that the N,N-bis(2-hydroxypropyl) tallow amide compounds in the test item do not have pKa values in the pH range 1-14 and that in this pH range they are in their non-ionised form. The HPLC analysis was therefore performed without buffering of the mobile phase (neutral pH).

 

Solutions of reference substances with known log Koc values based on soil adsorption data and the test item were analysed. The capacity factor (k') of each compound was calculated from its retention time. The log k’ values of the references substances were plotted against the known log Koc values. A linear regression program was used to calculate the calibration curve. Linear regression analysis was performed using the least squares method. The coefficient of correlation (r) was calculated. The log Koc value for the test item was calculated by substituting its mean log k’ in the calibration curve. The value of log Koc obtained from duplicate measurements was within ± 0.25 log units.

Results

In the chromatogram of the test solution, six major and several smaller test item peaks were observed. Peak area percentages were not calculated since compounds did not all elute in the isocratic part of the analysis.

The smaller peaks were observed at a retention time between 1.1 and 11.8 minutes.

The equation of the regression line was: log k’ = 0.315 x log Koc – 0.850 (r = 0.98, n = 16).

Conclusion

The HPLC method using soil-adsorption-reference data was applied for the determination of the adsorption coefficient (Koc) of MLA-3202.

The Koc and log Koc values of the test item at neutral pH were:

 

	Koc	Log Koc
Test item – peak 1 Test item – peak 2 Test item – peak 3 Test item – peak 4 Test item – peak 5 Test item – peak 6	2.5 x 10^5 6.4 x 10^5 1.1 x 10^6 2.1 x 10^6 >2.1 x 10^6 >2.1 x 10^6	5.4 5.8 6.1 6.3 >6.3 >6.3

 

Description of key information

The HPLC method using soil-adsorption-reference data was applied for the determination of the adsorption coefficient (Koc) of MLA-3202.

The Koc and log Koc values of the test item at neutral pH were:

 

	Koc	Log Koc
Test item – peak 1 Test item – peak 2 Test item – peak 3 Test item – peak 4 Test item – peak 5 Test item – peak 6	2.5 x 10^5 6.4 x 10^5 1.1 x 10^6 2.1 x 10^6 >2.1 x 10^6 >2.1 x 10^6	5.4 5.8 6.1 6.3 >6.3 >6.3

 

Key value for chemical safety assessment

Koc at 20 °C:

6 400 000

Additional information

 The purpose of the study was to determine the following physico-chemical properties for MLA-3202:

Adsorption coefficient

 

The principle of the test method is similar to that of the OECD guideline no. 117: "Partition coefficient (n-octanol/water), high performance liquid chromatography (HPLC) method".

While passing through the column along with the mobile phase the test item interacts with the stationary phase. As a result of partitioning between mobile and stationary phases, the test item is retarded. The dual composition of a cyanopropyl stationary phase, having polar and non-polar sites allows for interaction of polar and non-polar groups of a molecule in a similar way as is the case for organic matter in soil or sewage sludge matrices. This enables the relationship between the retention time on the column and the Koc on organic matter to be established.

 

The test item is a UVCB. In order to determine whether the N,N-bis(2-hydroxypropyl) tallow amide compounds in the test item are ionised for 10% or more in the pH range 5.5-7.5, the pKa values of the C16:0 and C18:1 compounds were calculated using the Perrin calculation method (pKalc 5.0, module in Pallas 3.0, CompuDrug International San Francisco, CA, USA). The calculations showed that the N,N-bis(2-hydroxypropyl) tallow amide compounds in the test item do not have pKa values in the pH range 1-14 and that in this pH range they are in their non-ionised form. The HPLC analysis was therefore performed without buffering of the mobile phase (neutral pH).

 

Solutions of reference substances with known log Koc values based on soil adsorption data and the test item were analysed. The capacity factor (k') of each compound was calculated from its retention time. The log k’ values of the references substances were plotted against the known log Koc values. A linear regression program was used to calculate the calibration curve. Linear regression analysis was performed using the least squares method. The coefficient of correlation (r) was calculated. The log Koc value for the test item was calculated by substituting its mean log k’ in the calibration curve. The value of log Koc obtained from duplicate measurements was within ± 0.25 log units.

Results

In the chromatogram of the test solution, six major and several smaller test item peaks were observed. Peak area percentages were not calculated since compounds did not all elute in the isocratic part of the analysis.

The smaller peaks were observed at a retention time between 1.1 and 11.8 minutes.

The equation of the regression line was: log k’ = 0.315 x log Koc – 0.850 (r = 0.98, n = 16). 

[LogKoc: 6.3]