(Z)-N-octadec-9-enylhexadecan-1-amide

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:

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.

Description of key information

Log Koc > 5.6, OECD 121,  (log Koc = 8.81 (KOCWIN v2.00))

Additional information

(Z)-N-Octadec-9-enylhexadecan-1-amide (CAS No. 16260-09-6) is expected to adsorb to suspended solids and sediment based upon a measured log Koc of > 5.6. The adsorption coefficient has been determined to be greater than 4.27E5 (log Koc > 5.6) using the HPLC screening method according to OECD 121. The test substance is highly insoluble in water and as the test item had a high affinity for the stationary phase of the column, the mobile phase was adjusted to 100% tetrahydrofuran 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.