Fatty acids, C9, hexaesters with dipentaerythritol

Adsorption / desorption

Link to relevant study record(s)

Reference

Endpoint:

adsorption / desorption: screening

Remarks:

adsorption

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Study period:

21 Jan - 20 May 1999

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

Read across study

Justification for type of information:

Based on its composition and physico chemical properties, fatty acids, C5-9, hexaesters with dipentaerythritol is considered to be a suitable read across substance to address the adsorption endpoint of the test substance, fatty acids, C9, hexaesters with dipentaerythritol.

Reason / purpose for cross-reference:

read-across source

Qualifier:

according to guideline

Guideline:

other: OECD draft document (1997): Estimation of the Adsorption Coefficient (Koc) on Soil and on Sewage Sludge using HPLC.

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

The Department of Health of the Government of the United Kingdom 21 Jul 1998 (date of inspection 23 Mar 1998)

Type of method:

HPLC estimation method

Media:

soil/sewage sludge

Test temperature:

Column temperature: 40 °C

Details on study design: HPLC method:

EQUIPMENT
- Apparatus: HPLC
- Type: Hewlett-Packard 1050
- Type, material and dimension of analytical (guard) column: Hypersil 5 µm CN-BDS, 250 mm x 4.6 mm
- Detection system: UV at 210 nm

MOBILE PHASES
- Type: 55% methanol/45% water (v/v)
- Solutes for dissolving test and reference substances: The test and reference substances were dissolved in methanol.

DETERMINATION OF DEAD TIME
- Method: The dead time was determined by measuring the retention time of formamide.

REFERENCE SUBSTANCES
- Identity: Acetaniline, phenol, atrazine, linuron, naphthalene, endosulphan-alcohol, fenthion, alpha-endosulfan, phenanthrene, diclofop-methyl, DDT

DETERMINATION OF RETENTION TIMES
- Quantity of test substance introduced in the column: 10 - 25 µl of 10 g/L test substance solution
- Quantity of reference substances: 10 - 25 µl of 92 - 172 mg/L reference substance solutions

REPETITIONS
- Number of determinations: 2

EVALUATION
- Calculation of capacity factors k': capacity factor = (retention time - dead time)/dead time
- Calculation of retention times: experimental determination
- Determination of the log Koc value: calibration curve

Key result

Type:

log Koc

Value:

> 5.63 dimensionless

Temp.:

40 °C

Type:

Koc

Value:

426 579.5 L/kg

Temp.:

40 °C

Details on results (HPLC method):

- Retention times of reference substances used for calibration: Formamide 3.198 min, acetaniline 3.52 min, phenol 3.488 min, atrazine 4.004 min, linuron 4.479 min, naphthalene 5.125 min, endosulphan-alcohol 6.248 min, fenthion 6.804 min, alpha-endosulfan 12.814 min, phenanthrene 8.498 min, diclofop-methyl 12.288 min, DDT 36.506 min
- The test material components were found to bond so strongly to the HPLC column's stationary phase that they failed to elute over the run time covered by the calibration. To force the components to elute, the polarity of the mobile phase was reduced by increasing the organic solvent content to 100%; this adjustment to the aluent was made at a run time greater than the retention time of DDT.
- Details for calibration curve: r2 = 0.99

Table 1: Results for the test substance

Injection	Retention time (min)	Capacity factor (k)	log k	log Koc
1	> 36.506	> 10.415	> 1.018	> 5.63
2	> 36.506	> 10.415	> 1.018	> 5.63

Table 2: The capacity factor (k) and log Koc values for the reference standards that were used to establish the calibration curve

Reference standard	Capacity factor (k)	log k	log Koc
Acetaniline	0.101	- 0.997	1.25
Phenol	0.09053	- 1.043	1.32
Atrazine	0.252	- 0.599	1.81
Linuron	0.485	- 0.314	2.59
Naphthalene	0.603	- 0.220	2.75
Andosulphan-alcohol	0.954	- 0.02058	3.02
Fenthion	1.127	0.05209	3.31
Alpha endosulfan	3.007	0.478	4.09
Phenanthrene	1.657	0.219	4.09
Diclofop-methyl	2.842	0.454	4.20
DDT	10.415	1.018	5.63

Validity criteria fulfilled:

yes

Conclusions:

Under the study conditions, the retention time of the test substance exceeded the range of the calibration curve, therefore the log Koc was considered to be > 5.63, the highest log Koc of the reference substances.

Executive summary:

A study was conducted to determine the log Koc of the read across substance, fatty acids, C5-9, hexaesters with dipentaerythritol, according to the OECD draft document (1997): ‘Estimation of the Adsorption Coefficient (Koc) on Soil and on Sewage Sludge using HPLC’, in compliance with GLP. Its individual constituents were found to bond so strongly to the HPLC column stationary phase that they failed to elute over the time covered by the calibration. To force components to elute, the polarity of the mobile phase was reduced by increasing the organic solvent content to 100%; this adjustment to the eluent was made at a run time greater than the retention time of DDT. The retention times of the 11 reference substances used for calibration were as follows: formamide 3.198 min, acetaniline 3.52 min, phenol 3.488 min, atrazine 4.004 min, linuron 4.479 min, naphthalene 5.125 min, endosulphan-alcohol 6.248 min, fenthion 6.804 min, alpha-endosulfan 12.814 min, phenanthrene 8.498 min, diclofop-methyl 12.288 min, DDT 36.506 min. Under the study conditions, the retention time of the test substance exceeded the range of the calibration curve, therefore the log Koc was considered to be > 5.63, the highest log Koc of the reference substances (Lumsden, 2000).

Description of key information

Log Koc > 5.63.

Additional information

A study was conducted to determine the log Koc of the read across substance, fatty acids, C5-9, hexaesters with dipentaerythritol, according to the OECD draft document (1997): ‘Estimation of the Adsorption Coefficient (Koc) on Soil and on Sewage Sludge using HPLC’, in compliance with GLP. Its individual constituents were found to bond so strongly to the HPLC column stationary phase that they failed to elute over the time covered by the calibration. To force components to elute, the polarity of the mobile phase was reduced by increasing the organic solvent content to 100%; this adjustment to the eluent was made at a run time greater than the retention time of DDT. The retention times of the 11 reference substances used for calibration were as follows: formamide 3.198 min, acetaniline 3.52 min, phenol 3.488 min, atrazine 4.004 min, linuron 4.479 min, naphthalene 5.125 min, endosulphan-alcohol 6.248 min, fenthion 6.804 min, alpha-endosulfan 12.814 min, phenanthrene 8.498 min, diclofop-methyl 12.288 min, DDT 36.506 min. Under the study conditions,the retention time of the test substance exceeded the range of the calibration curve, therefore the log Koc was considered to be > 5.63, the highest log Koc of the reference substances (Lumsden, 2000).