Dioleamide

Adsorption / desorption

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

adsorption / desorption, other

Type of information:

(Q)SAR

Adequacy of study:

key study

Study period:

2017

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

Remarks:

The substance is outside of the domain of the training set (logKow of the training set: -2.11 - 8.12; logKow of the target molecule is 15.08

Principles of method if other than guideline:

- Software tool(s) used including version: EPISUITE V4.11
- Model(s) used:KOCWIN Program (v2.00)
- Model description: see field ''Attached justification'
- Justification of QSAR prediction: see field 'Justification for type of information', 'Attached justification' and/or 'Cross-reference'

GLP compliance:

no

Type of method:

other: QSAR calculation

Computational methods:

- Adsorption and desorption coefficients (Kd):
- Adsorption coefficient per organic carbon (Koc): from moleculat coinectivity index and from log Kow. See attached document

Key result

Sample No.:

#1

Type:

Koc

Value:

1 459 000 000 L/kg

Conclusions:

The KOCWIN Program (v2.00) estimated Koc (from MCI) is 1.459E+9 L/kg (logKoc = 9.1640). This indicates very stron sorption to soil and sediment, with negligible migration potential to groundwater.

Executive summary:

The KOCWIN Program (v2.00) estimated Koc (from MCI) is 1.459E+9 L/kg (logKoc = 9.1640). This indicates very stron sorption to soil and sediment, with negligible migration potential to groundwater.

Reference 2

Endpoint:

adsorption / desorption: screening

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

28 Aug - 18 Oct 2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP-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))

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))

GLP compliance:

yes (incl. QA statement)

Remarks:

The Department of Health of the Government of the United Kingdom

Type of method:

HPLC estimation method

Radiolabelling:

no

Test temperature:

30 °C

Details on study design: HPLC method:

EQUIPMENT
- Apparatus: HPLC System: Agilent Technologies 1100 Series, incorporating autosampler
- Type, material and dimension of analytical (guard) column: Cyanopropyl reverse phase HPLC column containing lipophilic and polar moieties: Waters XSelect HSS Cyano 5µm (150 x 4.6 mm id), Flow-rate: 1.0 mL/min, Injection volume: 10 µL
- Detection system: UV detector wavelength: 210 nm

MOBILE PHASES
- Type:
Phase A: methanol:reverse osmosis water (55:45 v/v)
Phase B: THF
- pH: 6.62

DETERMINATION OF DEAD TIME
- Method: The dead time was determined by measuring the retention time of formamide (purity 99.94%, 614 mg/L solution in methanol:water 55:45 v/v)

REFERENCE SUBSTANCES
Solutions of reference standards were prepared in methanol.

- Identity (purity in %, concentration in mg/L): Phenol (99+, 114), Atrazine (98.8, 105), Isoproturon (99.9, 100), Triadimenol (98.4, 133), Linuron (99.7, 98.0), Naphthalene (99+, 129), Endosulfan-diol (99.9, 116), Fenthion (98.3, 146), a-Endosulfan (99.6, 132), Diclofop-methyl (99.2, 124), Phenanthrene (97, 134), DDT (98, 157)


EVALUATION
- Calculation of capacity factors k': k' = (tr - t0) / t0 with tr = retention time and t0 dead time in min.
- Determination of the log Koc value: Log10 Koc = (Log10 k' - A) / B with Koc = adsorption coefficient, k' = capacity factor, A = intercept of the calibration curve, B = slope of the calibration curve

Analytical monitoring:

no

Type:

log Koc

Value:

> 5.63

Type:

Koc

Value:

> 427 000

Tables: Retention times of the dead time and the retention times, capacity factors (k') and log10 Koc values for the reference standards.

Dead Time	Retention Time (mins)		Mean Retention Time (mins)
	Injection 1	Injection 2
Formamide	1.955	1.958	1.957

Standard	Retention Time (mins)		Mean Retention Time (mins)	Capacity Factor (k')	Log10 k'	Log10 Koc
	Injection 1	Injection 2
Phenol	2.608	2.608	2.608	0.333	-0.478	1.32
Atrazine	3.782	3.785	3.783	0.934	-2.98 x 10^-2	1.81
Isoproturon	4.078	4.078	4.078	1.08	3.52 x 10^-2	1.86
Triadimenol	5.585	5.582	5.583	1.85	0.268	2.40
Linuron	5.796	5.793	5.795	1.96	0.293	2.59
Naphthalene	4.976	4.978	4.977	1.54	0.189	2.75
Endosulfan-diol	7.334	7.329	7.331	2.75	0.439	3.02
Fenthion	8.794	8.814	8.804	3.50	0.544	3.31
a-Endosulfan	12.783	12.751	12.767	5.53	0.742	4.09
Diclofop-methyl	13.666	13.663	13.664	5.98	0.777	4.20
Phenanthrene	9.634	9.631	9.632	3.92	0.594	4.09
DDT	27.943	27.921	27.932	13.3	1.12	5.63

Table: Retention times, capacity factor and log10 Koc values determined

Injection	Retention Time (mins)	Capacity Factor (k')	Logio k'	Logio Koc	Adsorption Coefficient
1	39.483	>13.3	>1.12	>5.63	>4.27 x 10^5
2	39.477	>13.3	>1.12	>5.63	>4.27 x 10^5

As the test item had a high affinity for the stationary phase of the column, the mobile phase was adjusted to 100% THF shortly after the retention time of DDT to elute the sample. As the slope of the calibration curve for the reference standards showed good first order correlation and as the retention times between duplicate injections for each solution were consistent, the HPLC method was considered valid for the determination of adsorption coefficient. Based on the chromatographic data, the test item was considered to be stable during the test procedure.

Key value for chemical safety assessment

Koc at 20 °C:

1 459 000 000

Additional information

[LogKoc: 9.164]