Fatty acids, C18-unsatd., phosphates

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:

January-July 2018

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))

Deviations:

no

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))

Deviations:

no

GLP compliance:

yes

Type of method:

HPLC estimation method

Media:

soil

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: 0101891886
- Expiration date of the lot/batch: 14 September 2018 (retest date)

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: At room temperature
- Stability under test conditions: stable
- Solubility and stability of the test substance in the solvent/vehicle: Not indicated

Radiolabelling:

not specified

Test temperature:

30

Details on study design: HPLC method:

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.
According to the guidelines, the determination of the Koc for test items that are ionized for at least 10% within pH 5.5 to 7.5 should be performed with both the ionized and non-ionized form. Since the test item is an UVCB, the HPLC method was performed at pH 7 and pH 2.
Solutions of reference substances with known log Koc values based on soil adsorption data and the test item were analyzed. 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 monitoring:

yes

Remarks:

See details in section "information on material and methods incl. tables"

Key result

Sample No.:

#1

Type:

log Koc

Value:

1.26 dimensionless

pH:

2

Temp.:

30 °C

Sample No.:

#2

Type:

log Koc

Value:

3.36 dimensionless

pH:

2

Temp.:

30 °C

Sample No.:

#3

Type:

log Koc

Value:

3.43 dimensionless

pH:

2

Temp.:

30 °C

Sample No.:

#4

Type:

log Koc

Value:

3.76 dimensionless

pH:

2

Temp.:

30 °C

Sample No.:

#5

Type:

log Koc

Value:

3.83 dimensionless

pH:

2

Temp.:

30 °C

Sample No.:

#6

Type:

log Koc

Value:

4.46 dimensionless

pH:

2

Temp.:

30 °C

Sample No.:

#7

Type:

log Koc

Value:

5.02 dimensionless

pH:

2

Temp.:

30 °C

Sample No.:

#8

Type:

log Koc

Value:

5.21 dimensionless

pH:

2

Temp.:

30 °C

Sample No.:

#9

Type:

log Koc

Value:

> 5.63 dimensionless

pH:

2

Temp.:

30 °C

Sample No.:

#10

Type:

log Koc

Value:

> 5.63 dimensionless

pH:

2

Temp.:

30 °C

Sample No.:

#11

Type:

log Koc

Value:

> 5.63 dimensionless

pH:

2

Temp.:

30 °C

Sample No.:

#12

Type:

log Koc

Value:

> 5.63 dimensionless

pH:

2

Temp.:

30 °C

Sample No.:

#1

Type:

log Koc

Value:

1.26 dimensionless

pH:

7

Temp.:

30 °C

Remarks on result:

other: Same reuslts for peaks from 1 to 4

Sample No.:

#5

Type:

log Koc

Value:

0.9 dimensionless

pH:

7

Temp.:

30 °C

Sample No.:

#6

Type:

log Koc

Value:

1.49 dimensionless

pH:

7

Temp.:

30 °C

Sample No.:

#7

Type:

log Koc

Value:

4.42 dimensionless

pH:

7

Temp.:

30 °C

Sample No.:

#8

Type:

log Koc

Value:

5.16 dimensionless

pH:

7

Temp.:

30 °C

Sample No.:

#9

Type:

log Koc

Value:

> 5.63 dimensionless

pH:

7

Temp.:

30 °C

Details on results (HPLC method):

See list of figures in the attached background material section and the tables in the section "any other information in results incl. tables".

pH 7
UPLC-UV chromatograms of the test item solution and corresponding blank are shown in Figure 16 and Figure 17, respectively. In the chromatogram of the test solution, several peaks were observed.
The results of the HPLC method are given in Table 36. Figure 18 shows the calibration curve of the log k’ of the reference substances as function of log Koc. The equation of the regression line was: log k’ = 0.318 ´ log Koc – 0.863 (r = 0.98, n = 16).

pH 2
UPLC-UV chromatograms of the test item solution and corresponding blank are shown in Figure 19 and Figure 20, respectively. In the chromatogram of the test solution, several peaks were observed.
The results of the HPLC method are given in Table 37. Figure 21 shows the calibration curve of the log k’ of the reference substances as function of log Koc. The equation of the regression line was: log k’ = 0.317 ´ log Koc – 0.850 (r = 0.98, n = 14).
 

Transformation products:

not measured

Table 36      
pH 7: K_ocof the Test Item

Substance	Retention time (min)			log Koc	Koc	Peak area (%)
	tr,1	tr,2	mean
Formamide (t0)	0.716	0.715	0.716
Acetanilide	0.917	0.922	0.920	1.26
Monuron	1.120	1.122	1.121	1.99
2,5-Dichloroaniline	1.258	1.262	1.260	2.55
Naphthalene	1.468	1.469	1.469	2.75
Benzoic acid phenylester	1.749	1.751	1.750	2.87
Fenthion	2.271	2.266	2.269	3.31
Phenanthrene	2.514	2.511	2.513	4.09
4,4’-DDT	5.921	5.851	5.886	5.63
Test item – peak 1	0.457	0.458	0.458	< 1.26	<1.8´10^1	15
Test item – peak 2	0.533	0.534	0.534	< 1.26	<1.8´10^1	30
Test item – peak 3	0.656	0.657	0.657	< 1.26	<1.8´10^1	1.6
Test item – peak 4	0.722	0.723	0.723	< 1.26	<1.8´10^1	2.4
Test item – peak 5	0.904	0.906	0.905	0.90	7.9´10^0	6.5
Test item – peak 6	1.007	1.009	1.008	1.49	3.1´10^1	21
Test item – peak 7	3.216	3.210	3.213	4.42	2.6´10^4	18
Test item – peak 8	5.004	4.988	4.996	5.16	1.4´10^5	1.1
Test item – peak 9	12.105	12.122	12.114	> 5.63	>4.3´10^5	5.4

 

Table 37      
pH 2: K_ocof the Test Item

Substance	Retention time (min)			log Koc	Koc	Peak area (%)
	tr,1	tr,2	mean
Formamide (t0)	0.716	0.714	0.715
Acetanilide	0.922	0.920	0.921	1.26
Monuron	1.123	1.121	1.122	1.99
Naphthalene	1.464	1.464	1.464	2.75
Benzoic acid phenylester	1.723	1.721	1.722	2.87
Fenthion	2.280	2.280	2.280	3.31
Phenanthrene	2.504	2.501	2.503	4.09
4,4’-DDT	6.069	6.071	6.070	5.63
Test item – peak 1	0.907	0.907	0.907	< 1.26	<1.8´10^1	2.0
Test item – peak 2	1.893	1.893	1.893	3.36	2.3´10^3	1.6
Test item – peak 3	1.950	1.951	1.951	3.43	2.7´10^3	4.4
Test item – peak 4	2.291	2.297	2.294	3.76	5.8´10^3	4.2
Test item – peak 5	2.363	2.374	2.369	3.83	6.7´10^3	9.2
Test item – peak 6	3.160	3.161	3.161	4.36	2.3´10^4	10
Test item – peak 7	4.663	4.667	4.665	5.02	1.0´10^5	1.8
Test item – peak 8	5.248	5.252	5.250	5.21	1.6´10^5	8.5
Test item – peak 9	7.218	7.220	7.219	> 5.63	>4.3´10^5	33
Test item – peak 10	11.501	11.504	11.503	> 5.63	>4.3´10^5	14
Test item – peak 11	15.644	15.717	15.681	> 5.63	>4.3´10^5	1.5
Test item – peak 12	23.123	23.209	23.166	> 5.63	>4.3´10^5	8.6

 

Table 38.

The K_ocand log K_ocvalues of the test item at neutral pH and pH 2 were:

	neutral pH			pH 2
	Koc	log Koc	Peak area (%)	Koc	log Koc	Peak area (%)
Test item – peak 1	<1.8´10^1	< 1.26	15	<1.8´10^1	< 1.26	2.0
Test item – peak 2	<1.8´10^1	< 1.26	30	2.3´10^3	3.36	1.6
Test item – peak 3	<1.8´10^1	< 1.26	1.6	2.7´10^3	3.43	4.4
Test item – peak 4	<1.8´10^1	< 1.26	2.4	5.8´10^3	3.76	4.2
Test item – peak 5	7.9´10^0	0.90	6.5	6.7´10^3	3.83	9.2
Test item – peak 6	3.1´10^1	1.49	21	2.3´10^4	4.36	10
Test item – peak 7	2.6´10^4	4.42	18	1.0´10^5	5.02	1.8
Test item – peak 8	1.4´10^5	5.16	1.1	1.6´10^5	5.21	8.5
Test item – peak 9	>4.3´10^5	> 5.63	5.4	>4.3´10^5	> 5.63	33
Test item – peak 10	-	-	-	>4.3´10^5	> 5.63	14
Test item – peak 11	-	-	-	>4.3´10^5	> 5.63	1.5
Test item – peak 12	-	-	-	>4.3´10^5	> 5.63	8.6

Validity criteria fulfilled:

yes

Conclusions:

The HPLC method using soil-adsorption-reference data was applied for the determination of the adsorption coefficient (Koc) of Fatty acids, C18-unsatd., phosphates.
The Koc and log Koc values of the test item at neutral pH and pH 2 were at 12 peaks. The Log Koc range from 1.26 to 5.63. List of results foudn table 38 in section "any other information on results incl. tables".

Description of key information

The HPLC method using soil-adsorption-reference data was applied for the determination of the adsorption coefficient (K_oc)of Fatty acids, C18-unsatd., phosphates.It followed EC C-19 and OECD 121 Guidance. The K_ocand log K_ocvalues of the test item at neutral pH and pH 2 were:

pH7: log Koc : range from <1.26 - >5.63

pH2: log Koc : range from <1.26 - >5.63

For CSA purposes, a value of 5.63 was chosen.

Key value for chemical safety assessment

Koc at 20 °C:

5.63