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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:

03 and 08 June 2005

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Study conducted in compliance with agreed protocols, with no or minor deviations from standard test guidelines and/or minor methodological deficiencies, which do not affect the quality of the relevant results.

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

Remarks:

The work described was performed in compliance with UK GLP standards (Schedule 1, Good Laboratory Practice Regulations 1999 (SI 1999/3106 as amended by SI 2004/0994)).

Type of method:

HPLC estimation method

Media:

sewage sludge

Radiolabelling:

no

Test temperature:

Column temperature = 40.0 ºC

Details on study design: HPLC method:

EQUIPMENT
- Apparatus:
- Type: Agilent Technologies 1100, incorporating autosampler and workstation
- Type, material and dimension of analytical (guard) column: Genesis CN 120Å (250 x 4.6 mm id)
- Detection system: Refractive index


MOBILE PHASES
- Type: tetrahydrofuran:water (55:45 v/v)
- Experiments with additives carried out on separate columns: no
- pH: 7.0, adjusted using 0.1 m sodium hydroxide
- Solutes for dissolving test and reference substances: tetrahydrofuran


DETERMINATION OF DEAD TIME
- Method: by means of homologous series / by inert substances which are not retained by the column
The dead time was determined by measuring the retention time of formamide

REFERENCE SUBSTANCES
- Identity: Acetanilide, Phenol, Atrazine, Isoproturon, Triadimenol, Linuron, Naphthalene, Endosulfan-diol, Fenthion, -Endosulfan, Phenanthrene , Diclofop-methyl and DDT


DETERMINATION OF RETENTION TIMES
- Quantity of test substance introduced in the column: 0.5070 g
- Quantity of reference substances:
- Intervals of calibration:


REPETITIONS
- Number of determinations: 2


EVALUATION
- Calculation of capacity factors k': >2.22
- Calculation of retention times: >9.5
- Determination of the log Koc value: >5.63

Type:

Koc

Value:

> 427

Type:

log Koc

Value:

> 5.63

Details on results (HPLC method):

- Retention times of reference substances used for calibration:
- Details of fitted regression line (log k' vs. log Koc):
- Graph of regression line attached
- Average retention data for test substance:

A calibration curve was created using the following results as reference standards:

Dead Time	Retention Time (mins)		Mean Retention Time (mins)
	Injection 1	Injection 2
Formamide	2.947	2.949	2.948

Standard	Retention Time (mins)		Mean Retention Time (mins)	Capacity Factor (k)	Log10k	Log10 Koc
	Injection 1	Injection 2
Acetanilide	3.754	3.753	3.754	0.237	-0.563	1.25
Phenol	4.215	4.218	4.217	0.430	-0.366	1.32
Atrazine	4.612	4.616	4.614	0.565	-0.248	1.81
Isoproturon	4.198	4.199	4.199	0.424	-0.372	1.86
Triadimenol	4.694	4.690	4.692	0.592	-0.228	2.40
Linuron	4.635	4.645	4.640	0.574	-0.241	2.59
Naphthalene	5.263	5.263	5.263	0.785	-0.105	2.75
Endosulfan-diol	4.981	4.985	4.983	0.690	-0.161	3.02
Fenthion	5.537	5.542	5.540	0.879	-5.60 x 10^-2	3.31
a-Endosulfan	6.948	6.947	6.948	1.36	0.132	4.09
Phenanthrene	5.604	5.601	5.603	0.900	-4.55 x 10^-2	4.09
Diclofop-methyl	6.325	6.322	6.324	1.15	5.88 x 10^-2	4.20
DDT	7.954	7.946	7.950	1.70	0.230	5.63

The retention times, capacity factors and log₁₀K_ocvalues determined for the sample are shown in the following table:

Injection	Retention Time (mins)	Capacity Factor (k)	Log10k	Log10Koc
1	>9.5	>2.22	>0.347	>5.63
2	>9.5	>2.22	>0.347	>5.63

Mean log₁₀K_oc:                       >5.63
Adsorption coefficient: >4.27 x 10⁵

Validity criteria fulfilled:

yes

Conclusions:

- adsorption coefficient (Koc): >4.27 x 105, log10 Koc >5.63

Executive summary:

The determination was carried out for 'Paraffin waxes (Fischer-Tropsch), full range, C15-50 - branched and linear' using the HPLC screening method, Method C19 of Commission Directive 2001/59/EC (which constitutes Annex V of Council Directive 67/548/EEC).

The adsorption coefficient (Koc) of the test material has been determined to be >4.27 x 105, log10 Koc >5.63.

Description of key information

adsorption coefficient (Koc) of the test material: >4.27E5, log10 Koc >5.63

Key value for chemical safety assessment

Koc at 20 °C:

5.63

Additional information

The determination was carried out using the HPLC screening method, Method C19 of Commission Directive 200l/59/EC (which constitutes Annex V of Council Directive 67/548/EEC).

The adsorption coefficient (Koc) of the test material has been determined to be >4.27 x 10⁵, log₁₀ Koc >5.63

The test material was known to primarily be a complex mixture of alkanes. As the test material eluted after the mobile phase had been adjusted to 100% solvent, all components were deemed to be greater than that of the highest calibration standard.

EUSES 2.1.2 includes QSAR equations for the prediction of the adsorption coefficient Koc from Kow. The appropriate equation is for the ‘hydrophobics’ group, which is:

log Koc = 0.10 + 0.81log Kow

Koc for each block is calculated from the weighted average Kow for the block, given in Table 1.xxx of the Chemical Safety Report and in the overall Physical and chemical properties endpoint summary in IUCLID.

[LogKoc: 0.751]